Standard plans for southern pine bridges

Treesearch

P. D. Hilbrich Lee; M. A. Ritter; M. H. Triche

1995-01-01

The development of standardized timber bridge plans and specifications is a key element in improving design and construction practices. The bridge plans presented were developed as a cooperative effort between the USDA Forest Service, Forest Products Laboratory (FPL); the University of Alabama; and the Southern Pine Council and are the first step in developing...

Development of bridge girder movement criteria for accelerated bridge construction.

DOT National Transportation Integrated Search

2014-06-01

End diaphragms connect multiple girders to form a bridge superstructure system for effective resistance to earthquake loads. Concrete : girder bridges that include end diaphragms consistently proved to perform well during previous earthquake events. ...

Final report bridge design system analysis and modernization.

DOT National Transportation Integrated Search

2016-09-27

The Bridge Design System (BDS) is an in-house software program developed by the Michigan Department of Transportations : (MDOT) Bridge Design Unit. The BDS designs bridges according to the required specifications, and outputs corresponding design ...

Development of a guide for prioritization of railway bridges for repair and replacement.

DOT National Transportation Integrated Search

2013-09-01

The objective of this study was to develop evaluation bases for the repair, rehabilitation, and replacement of existing : railway bridges. Considering the importance of bridges to the railway network, the research involved the review and : analysis o...

Laboratory study - laboratory testing of bridge deck mixes

DOT National Transportation Integrated Search

2003-03-01

The purpose of this investigation was to develop bridge deck mixes that will improve field performance and minimize cracking potential compared to MoDOT's current (B-2) bridge deck mix design. The mix designs developed in this study were tested and c...

Toward improving the performance of highway bridge approach slabs.

DOT National Transportation Integrated Search

2011-09-01

The objective of this study was to quantify the amount of rotation that could develop between an approach slab, after base settlement, and a bridge abutment. A better approach-bridge transition could then be developed by using a ductile concrete to d...

Bridge maintenance Program for the City of Columbia, Missouri : final report.

DOT National Transportation Integrated Search

2017-09-22

The goal of this project was to extend the service lives of bridges located in Columbia, Missouri. The objective of the project was to develop guidelines for bridge maintenance and preservation. The guidelines developed are focused on practical and i...

Developing a bridge scour warning system : technical summary.

DOT National Transportation Integrated Search

2016-09-01

Flooding and scour can be major threats to the integrity of bridges. During flood events, : scour at bridge piers and abutments can undermine the foundations of the bridge, causing : significant damage or even total structure loss. Because scour occu...

Developing a bridge scour warning system : final report.

DOT National Transportation Integrated Search

2016-09-01

Flooding and scour can be major threats to the integrity of bridges. During flood events, scour at bridge piers : and abutments can undermine the foundations of the bridge, causing significant damage or even total structure loss. : Because scour occu...

Developing a Tele-Robotic Platform for Bridge Inspection

DOT National Transportation Integrated Search

2011-05-01

There are many bridges in Virginia with high traffic volumes or difficult access conditions which make these bridges difficult and expensive to inspect. In addition, the inspection of many bridges exposes the inspectors to hazardous conditions such a...

Implementation of sustainability in bridge design, construction and maintenance.

DOT National Transportation Integrated Search

2012-12-01

The focus of this research is to develop a framework for more sustainable design and construction : processes for new bridges, and sustainable maintenance practices for existing bridges. The framework : includes a green rating system for bridges. The...

Analysis of past NBI ratings to determine future bridge preservation needs.

DOT National Transportation Integrated Search

2004-01-01

Bridge Management System (BMS) needs an analytical tool that can predict bridge element deterioration and answer questions related to bridge preservation. PONTIS, a comprehensive BMS software, was developed to serve this purpose. However, the intensi...

Development of a database for Louisiana highway bridge scour data : a program and manual.

DOT National Transportation Integrated Search

1999-10-01

A tremendous amount of scour data already exists for the highway bridges monitored by the Louisiana Department of Transportation and Development (DOTD). More than one hundred and twenty bridges are being monitored at a frequency of one to several tim...

Enhancement of welded steel bridge girders susceptible to distortion-induced fatigue : [technical summary].

DOT National Transportation Integrated Search

2014-10-01

Distortion-induced fatigue is a serious problem across the national bridge inventory, : affecting many steel bridges designed before the mid-1980s. Because distortion-induced : fatigue tends to develop in bridge connection details, near transverse el...

Development of improved connection details for adjacent prestressed member bridges.

DOT National Transportation Integrated Search

2017-06-01

Adjacent prestressed member girder bridges are economical systems for short spans and generally come in two types: adjacent box beam bridges and adjacent voided slab bridges. Each type provides the advantages of having low clearances because of their...

Implementation of sustainable and green design and construction practices for bridges.

DOT National Transportation Integrated Search

2012-12-01

The focus of this research is to develop a framework for more sustainable design and construction : processes for new bridges, and sustainable maintenance practices for existing bridges. The framework : includes a green rating system for bridges. The...

Structural monitoring of Rigolets Pass Bridge : LTRC technical summary report 437.

DOT National Transportation Integrated Search

2009-09-01

The Louisiana Department of Transportation and Development (LADOTD) has been gradually : introducing high performance concrete (HPC) into their bridge construction programs. The : Rigolets Pass Bridge is a 62-span bridge with a total length of 5,489 ...

Bilingual Resource Instruction for Development of Gainful Employment Skills. Project BRIDGES, 1987-88.

ERIC Educational Resources Information Center

Berney, Tomi D.; Adelman, Miriam

The Bilingual Resources for Development of Gainful Employment skills (Project BRIDGES) was a federally-funded program in its second year of a 3-year funding cycle. Project BRIDGES aimed at developing the academic and vocational skills of limited-English-proficient (LEP) students who had failed two or more classes and were at risk of dropping out.…

Bridge Displacement Monitoring Method Based on Laser Projection-Sensing Technology

PubMed Central

Zhao, Xuefeng; Liu, Hao; Yu, Yan; Xu, Xiaodong; Hu, Weitong; Li, Mingchu; Ou, Jingping

2015-01-01

Bridge displacement is the most basic evaluation index of the health status of a bridge structure. The existing measurement methods for bridge displacement basically fail to realize long-term and real-time dynamic monitoring of bridge structures, because of the low degree of automation and the insufficient precision, causing bottlenecks and restriction. To solve this problem, we proposed a bridge displacement monitoring system based on laser projection-sensing technology. First, the laser spot recognition method was studied. Second, the software for the displacement monitoring system was developed. Finally, a series of experiments using this system were conducted, and the results show that such a system has high measurement accuracy and speed. We aim to develop a low-cost, high-accuracy and long-term monitoring method for bridge displacement based on these preliminary efforts. PMID:25871716

A guidance manual for assessing scour potential using the South Carolina bridge-scour envelope curves

USGS Publications Warehouse

Benedict, Stephen T.; Caldwell, Andral W.; Feaster, Toby D.

2014-01-01

The U.S. Geological Survey, in cooperation with the South Carolina Department of Transportation, conducted a series of three field investigations of bridge scour in order to better understand regional trends of scour within South Carolina. The studies collected historic-scour data at approximately 200 riverine bridges including measurements of clear-water abutment, contraction, and pier scour, as well as live-bed contraction and pier scour. These investigations provided valuable insights for regional scour trends and yielded bridge-scour envelope curves for assessing scour potential associated with all components of scour at riverine bridges in South Carolina. The application and limitations of these envelop cureves were documents in three reports, Each repoort addresses different components of bridge scour and this, there is a need to develop an integrated procedure for applying the South Carolina bridge-scour envelope curves. To address this need, the U.S. Geological Survey and the South Carolina Department of Transportation initiated a cooperative effort to develop an integrated procedure and document the method in a guidance manual. In addition to developing the integrated procedure, field data from other investigations outside of South Carolina were used to verify the South Carolina bridge-source envelope curves.

Dynamic assessment of bridge deck performance considering realistic bridge-traffic interaction : research brief

DOT National Transportation Integrated Search

2017-09-01

This study is to develop simulation methodology to conduct the dynamic assessment of bridge deck performance subjected to traffic. Concrete bridge decks are exposed to daily traffic loads and may experience some surface cracking caused by excessive s...

Development of a precast bridge deck overhang system for the rock creek bridge.

DOT National Transportation Integrated Search

2008-12-01

Precast, prestressed panels are commonly used at interior beams for bridges in Texas. The use of these : panels provides ease of construction, sufficient capacity, and good economy for the construction of : bridges in Texas. Current practice for the ...

Remote bridge scour monitoring : a prioritization and implementation guideline

DOT National Transportation Integrated Search

1999-05-01

Having the largest bridge population in the nation, the state of Texas stands to gain much through the development of bridge scour-monitoring and evaluation practices. Because it has such a large bridge population to manage, the Texas Department of T...

Development of a sustainable UHPC bridge deck for movable bridges : [research project capsule].

DOT National Transportation Integrated Search

2015-11-01

Louisiana has approximately 160 movable bridges, mostly in the southern part of the state, which : places Louisiana among states with the highest inventory of movable bridges in the nation. These : transportation arteries are important for the econom...

Development of a Computational Framework for Big Data-Driven Prediction of Long-Term Bridge Performance and Traffic Flow

DOT National Transportation Integrated Search

2018-04-01

Consistent efforts with dense sensor deployment and data gathering processes for bridge big data have accumulated profound information regarding bridge performance, associated environments, and traffic flows. However, direct applications of bridge bi...

Flood Plain Information Bushkill Creek, Vicinity of Easton, Pennsylvania.

DTIC Science & Technology

1972-01-01

is a cement plant and numerous railroad sidings in the Borough of Stockertown. Further down- stream, in the Borough of Tatamy , development includes...several production and storage facirities and the local fire department. Below Tatamy , development again consists of scat- tered residential and...23,000 Bridge Bushkill St. Bridge 7.1 7,200 17,000 ( Tatamy , Pa.) Lehigh Valley R.R. 8.2 7,200 17,000 Bridge (Stockertown, Pa.) 8th Street Bridge 8.5

Two test level 4 bridge railing and transition systems for transverse timber deck bridges

Treesearch

Ronald K. Faller; Michael A. Ritter; Barry T. Rosson; Michael D. Fowler; Sheila R. Duwadi

2000-01-01

The Midwest Roadside Safety Facility, in cooperation with the Forest Products Laboratory, which is part of the U.S. Department of Agricultureas Forest Service, and FHWA, designed two bridge railing and approach guardrail transition systems for use on bridges with transverse glue-laminated timber decks. The bridge raging and transition systems were developed and crash...

Feasibility study of developing and creating a standardized subset of bridge plans.

DOT National Transportation Integrated Search

2015-09-01

This study investigated sizes and geometry of existing bridges in Colorado and investigated standard bridge systems used by : other entities. The study proposed standard bridge types advancing the goals of SHRP 2 R19A & B, the rapidest ABC : construc...

Development of a nondestructive evaluation method for FRP bridge decks

NASA Astrophysics Data System (ADS)

Brown, Jeff; Fox, Terra

2010-05-01

Open steel grids are typically used on bridges to minimize the weight of the bridge deck and wearing surface. These grids, however, require frequent maintenance and exhibit other durability concerns related to fatigue cracking and corrosion. Bridge decks constructed from composite materials, such as a Fiber-reinforced Polymer (FRP), are strong and lightweight; they also offer improved rideability, reduced noise levels, less maintenance, and are relatively easy to install compared to steel grids. This research is aimed at developing an inspection protocol for FRP bridge decks using Infrared thermography. The finite element method was used to simulate the heat transfer process and determine optimal heating and data acquisition parameters that will be used to inspect FRP bridge decks in the field. It was demonstrated that thermal imaging could successfully identify features of the FRP bridge deck to depths of 1.7 cm using a phase analysis process.

Development and construction of low-cracking high-performance concrete (LC-HPC) bridge decks : free shrinkage, moisture optimization and concrete production : final report.

DOT National Transportation Integrated Search

2009-08-01

The development and evaluation of low-cracking high-performance concrete (LC-HPC) for use in bridge decks : is described based on laboratory test results and experience gained during the construction of 14 bridges. This report : emphasizes the materi...

MASH TL-3 crash testing and evaluation of the TxDOT T631 Bridge Rail.

DOT National Transportation Integrated Search

2016-07-01

The Texas Type T631 bridge rail was developed as a low-cost, flexible bridge rail system for TL-2 : applications. Many of the features used for the system tested at MwRSF for TL-3 were incorporated into the : design developed for this project for MAS...

Development and construction of low-cracking high-performance concrete (LC-HPC) bridge decks : free shrinkage, moisture optimization and concrete production : summary report.

DOT National Transportation Integrated Search

2009-08-01

The development and evaluation of low-cracking high-performance concrete (LC-HPC) for use in bridge decks : is described based on laboratory test results and experience gained during the construction of 14 bridges. This report : emphasizes the materi...

Collaborative Professional Development in Chemistry Education Research: Bridging the Gap between Research and Practice

ERIC Educational Resources Information Center

Szteinberg, Gabriela; Balicki, Scott; Banks, Gregory; Clinchot, Michael; Cullipher, Steven; Huie, Robert; Lambertz, Jennifer; Lewis, Rebecca; Ngai, Courtney; Weinrich, Melissa; Talanquer, Vicente; Sevian, Hannah

2014-01-01

Professional development that bridges gaps between educational research and practice is needed. However, bridging gaps can be difficult because teachers and educational researchers often belong to different Communities of Practice, as their activities, goals, and means of achieving those goals often differ. Meaningful collaboration among teachers…

Development and evaluation of a dual purpose bridge health monitoring and weigh-in-motion system for a steel girder bridge : phase two.

DOT National Transportation Integrated Search

2016-06-30

The primary objective of this second phase is the further development, demonstration : and field evaluation of a permanent dual purpose bridge weigh-in-motion and health monitoring : system over an extended period of time. Calibrated test truck resul...

A Bridge to Active Learning: A Summer Bridge Program Helps Students Maximize Their Active-Learning Experiences and the Active-Learning Experiences of Others

PubMed Central

Cooper, Katelyn M.; Ashley, Michael; Brownell, Sara E.

2017-01-01

National calls to improve student academic success in college have sparked the development of bridge programs designed to help students transition from high school to college. We designed a 2-week Summer Bridge program that taught introductory biology content in an active-learning way. Through a set of exploratory interviews, we unexpectedly identified that Bridge students had developed sophisticated views of active learning, even though this was not an explicit goal of the program. We conducted an additional set of semistructured interviews that focused on active learning and compared the interviews of Bridge students with those from non-Bridge students who had been eligible for but did not participate in the program. We used the constant comparative method to identify themes from the interviews. We found that Bridge students perceived that, because they knew how to approach active learning and viewed it as important, they benefited more from active learning in introductory biology than non-Bridge students. Specifically, Bridge students seemed to be more aware of their own learning gains from participating in active learning. Compared with the majority of non-Bridge students, the majority of Bridge students described using a greater variety of strategies to maximize their experiences in active learning. Finally, in contrast to non-Bridge students, Bridge students indicated that they take an equitable approach to group work. These findings suggest that we may be able to prime students to maximize their own and other’s experiences in active learning. PMID:28232588

Vibration analysis of the Second Saikai Bridge—a concrete filled tubular (CFT) arch bridge

NASA Astrophysics Data System (ADS)

Yoshimura, Mistuhiro; Wu, Qingxiong; Takahashi, Kazuo; Nakamura, Shozo; Furukawa, Kazuyoshi

2006-02-01

Concrete-filled steel tubular (CFT) arch bridges have been rapidly developing in China since 1990. Research has focused on the static behavior, thermal stress and erection technique, however, and there has been very little research of natural vibrations and dynamic responses of these bridges. Japan's first CFT arch bridge in highway bridges, the Second Saikai Bridge, is now under construction in Nagasaki Prefecture. Furthermore, this bridge has a pedestrian bridge that is suspended under the girder, which is rare. Therefore, the natural vibration properties are examined, and the influence of pedestrian bridge structure on the natural vibration of main bridge is discussed first. Response analysis under a moving vehicle and pedestrian is carried out, and the response characteristics and response level are clarified. The natural vibrations and responses are compared to those of CFT arch bridges that have been constructed in China. Results show the fine performance of both main bridge and pedestrian bridge of the Second Saikai Bridge.

Precast concrete elements for accelerated bridge construction : laboratory testing, field testing, and evaluation of a precast concrete bridge, Black Hawk County.

DOT National Transportation Integrated Search

2009-01-01

The importance of rapid construction technologies has been recognized by the Federal Highway Administration (FHWA) and the Iowa : DOT Office of Bridges and Structures. Black Hawk County (BHC) has developed a precast modified beam-in-slab bridge (PMBI...

Accelerated bridge construction utilizing precast pier caps on state highway 69 over Turkey Creek, Huerfano County, CO.

DOT National Transportation Integrated Search

2014-07-01

The purpose of this report is to document Accelerated Bridge Construction (ABC) techniques on IBRD : (Innovative Bridge Research and Development) project 102470 for the construction of Bridge N-16-Q : on State Highway 69 over Turkey Creek. The constr...

Simplified bridge load rating methodology using the national bridge inventory file : user manual

DOT National Transportation Integrated Search

1988-08-01

The purpose of this research was to develop a computerized system to determine the adequacy of a bridge or group of bridges to carry specified overload vehicles. The system utilizes two levels of analysis. The Level 1 analysis is the basic rating sys...

Simplified bridge load rating methodology using the national bridge inventory file : program listing

DOT National Transportation Integrated Search

1987-08-01

The purpose of this research was to develop a computerized system to determine the adequacy of a bridge or group of bridges to carry specified overload vehicles. The system utilizes two levels of analysis. The Level 1 analysis is the basic rating sys...

Hydraulic and geomorphic monitoring of experimental bridge scour mitigation at selected bridges in Utah, 2003-05

USGS Publications Warehouse

Kenney, Terry A.; McKinney, Tim S.

2006-01-01

Unique bridge scour mitigation designs using concrete A-Jacks were developed by the Utah Department of Transportation and installed at the Colorado River Bridge at State Road 191 and the Green River Bridge at State Road 19. The U.S. Geological Survey monitored stream reaches at these sites by collecting streambed-topography and water-velocity data from 2003 through 2005. These data were acquired annually from a moving boat with an acoustic Doppler current profiler and a differential global positioning system. Raw unordered data were processed and readied for interpolation into organized datasets with DopplerMacros, a set of computer programs. Processed streambed topography data were geostatistically interpolated by using Ordinary Kriging, and inverse distance weighting interpolation was used in the development of the two-dimensional velocity datasets. These organized datasets of topography and velocity were developed for each survey of the two bridge sites. A comparison of the riverbed topography data for each survey was done. An increase in bed elevation related to the installation of the A-Jacks scour countermeasures is evident at the Colorado River Bridge at State Road 191. The three topographic datasets acquired after the installation at the Green River Bridge at State Road 19 show few changes.

Development of Murray Loop Bridge for High Induced Voltage

NASA Astrophysics Data System (ADS)

Isono, Shigeki; Kawasaki, Katsutoshi; Kobayashi, Shin-Ichi; Ishihara, Hayato; Chiyajo, Kiyonobu

In the case of the cable fault that ground fault resistance is less than 10MΩ, Murray Loop Bridge is excellent as a fault locator in location accuracy and the convenience. But, when the induction of several hundred V is taken from the single core cable which adjoins it, a fault location with the high voltage Murray Loop Bridge becomes difficult. Therefore, we developed Murray Loop Bridge, which could be applied even when the induced voltage of several hundred V occurs in the measurement cable. The evaluation of the fault location accuracy was done with the developed prototype by the actual line and the training equipment.

Field investigations of historic covered timber bridges in the USA

Treesearch

James Wacker; Travis Hosteng; Brent Phares

2012-01-01

The Federal Highway Administration is sponsoring a comprehensive research program on Historic Covered Timber Bridges in the USA. This national program's main purpose is to develop improved methods to preserve, rehabililate, and restore the timber bridge trusses that were developed during the early 1800s, and in many cases are still in service today. The overall...

Connecticut permanent long-term bridge monitoring network, volume 3 : monitoring of a multi-steel girder composite bridge - I-91 SB over the Mattabesset River in Cromwell (bridge #3078).

DOT National Transportation Integrated Search

2014-08-01

This report describes the instrumentation and data acquisition for a multi-girder, composite steel bridge in Connecticut. The : computer-based remote monitoring system was developed to collect information on the girder bending strains. The monitoring...

Building Better Bridges into STEM: A Synthesis of 25 Years of Literature on STEM Summer Bridge Programs

ERIC Educational Resources Information Center

Ashley, Michael; Cooper, Katelyn M.; Cala, Jacqueline M.; Brownell, Sara E.

2017-01-01

Summer bridge programs are designed to help transition students into the college learning environment. Increasingly, bridge programs are being developed in science, technology, engineering, and mathematics (STEM) disciplines because of the rigorous content and lower student persistence in college STEM compared with other disciplines. However, to…

Bridging knowledge, policies and practices across the ageing and disability fields: a protocol for a scoping review to inform the development of a taxonomy.

PubMed

Nalder, Emily Joan; Putnam, Michelle; Salvador-Carulla, Luis; Spindel, Andria; Batliwalla, Zinnia; Lenton, Erica

2017-10-25

Bridging is a term used to describe activities, or tasks, used to promote collaboration and knowledge exchange across fields. This paper reports the protocol for a scoping review which aims to identify and characterise peer reviewed evidence describing bridging activities, between the ageing and disability fields. The purpose is to clarify the concepts underpinning bridging to inform the development of a taxonomy, and identify research strengths and gaps. A scoping review will be conducted. We will search Medline, Cumulative Index to Nursing and Allied Health Literature, Embase, PsycInfo, Sociological Abstracts and the Cochrane Library, to identify peer reviewed publications (reviews, experimental, observational, qualitative designs and expert commentaries) describing bridging activities. Grey literature, and articles not published in English will be excluded. Two investigators will independently complete article selection and data abstraction to minimise bias. A data extraction form will be iteratively developed and information from each publication will be extracted: (1) bibliographic, (2) methodological, (3) demographic, and (4) bridging information. Qualitative content analysis will be used to describe key concepts related to bridging. To our knowledge, this will be the first scoping review to describe bridging of ageing and disability knowledge, services and policies. The findings will inform the development of a taxonomy to define models of bridging that can be implemented and further evaluated to enable integrated care and improve systems and services for those ageing with disability. Ethics is not required because this is a scoping review of published literature. Findings will be disseminated through stakeholder meetings, conference presentations and peer reviewed publication. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Development of risk models for Florida's bridge management system.

DOT National Transportation Integrated Search

2013-06-01

Florida Department of Transportation (FDOT) has been actively implementing the American Association of State Highway Transportation Officials (AASHTO) Pontis Bridge Management System (BMS), recently renamed AASHTOWare Bridge Management (BrM), to supp...

Characterization of railroad bridge service interruptions.

DOT National Transportation Integrated Search

2013-02-01

The Federal Railroad Administration contracted Transportation Technology Center, Inc., to study bridge problems that cause accidents or service interruptions and to use this information to evaluate the need to develop bridge monitoring systems. Exist...

Submerged flow bridge scour under clear water conditions

DOT National Transportation Integrated Search

2012-09-01

Prediction of pressure flow (vertical contraction) scour underneath a partially or fully submerged bridge superstructure : in an extreme flood event is crucial for bridge safety. An experimentally and numerically calibrated formulation is : developed...

Wireless vibration monitoring for damage detection of highway bridges

NASA Astrophysics Data System (ADS)

Whelan, Matthew J.; Gangone, Michael V.; Janoyan, Kerop D.; Jha, Ratneshwar

2008-03-01

The development of low-cost wireless sensor networks has resulted in resurgence in the development of ambient vibration monitoring methods to assess the in-service condition of highway bridges. However, a reliable approach towards assessing the health of an in-service bridge and identifying and localizing damage without a priori knowledge of the vibration response history has yet to be formulated. A two-part study is in progress to evaluate and develop existing and proposed damage detection schemes. The first phase utilizes a laboratory bridge model to investigate the vibration response characteristics induced through introduction of changes to structural members, connections, and support conditions. A second phase of the study will validate the damage detection methods developed from the laboratory testing with progressive damage testing of an in-service highway bridge scheduled for replacement. The laboratory bridge features a four meter span, one meter wide, steel frame with a steel and cement board deck composed of sheet layers to regulate mass loading and simulate deck wear. Bolted connections and elastomeric bearings provide a means for prescribing variable local stiffness and damping effects to the laboratory model. A wireless sensor network consisting of fifty-six accelerometers accommodated by twenty-eight local nodes facilitates simultaneous, real-time and high-rate acquisition of the vibrations throughout the bridge structure. Measurement redundancy is provided by an array of wired linear displacement sensors as well as a scanning laser vibrometer. This paper presents the laboratory model and damage scenarios, a brief description of the developed wireless sensor network platform, an overview of available test and measurement instrumentation within the laboratory, and baseline measurements of dynamic response of the laboratory bridge model.

Deployment of a Smart Structural Health Monitoring System for Long-Span Arch Bridges: A Review and a Case Study

PubMed Central

Chen, Zengshun; Zhou, Xiao; Wang, Xu; Dong, Lili; Qian, Yuanhao

2017-01-01

Structural health monitoring (SHM) technology for surveillance and evaluation of existing and newly built long-span bridges has been widely developed, and the significance of the technique has been recognized by many administrative authorities. The paper reviews the recent progress of the SHM technology that has been applied to long-span bridges. The deployment of a SHM system is introduced. Subsequently, the data analysis and condition assessment including techniques on modal identification, methods on signal processing, and damage identification were reviewed and summarized. A case study about a SHM system of a long-span arch bridge (the Jiubao bridge in China) was systematically incorporated in each part to advance our understanding of deployment and investigation of a SHM system for long-span arch bridges. The applications of SHM systems of long-span arch bridge were also introduced. From the illustrations, the challenges and future trends for development a SHM system were concluded. PMID:28925943

Crossing Bridges That Connect the Arts, Cognitive Development, and the Brain

ERIC Educational Resources Information Center

Peterson, Rita

2005-01-01

Crossing high bridges offers the opportunity to ponder views from a distance: to see connections between places at the ground level or ideas that are familiar, and to capture an overview of places or ideas that are yet to be explored. The purpose of this essay is to explore the figural bridges that connect the arts with cognitive development and…

Field testing and structural analysis of Burr arch covered bridges in Pennsylvania

Treesearch

Douglas Rammer; James Wacker; Travis Hosteng; Justin Dahlberg; Yaohua Deng

2016-01-01

The Federal Highway Administration sponsored a comprehensive research program on Historic Covered Timber Bridges in the USA. This national program's main purpose is to develop improved methods to preserve, rehabilitate, and restore timber bridge trusses that were developed during the early 1800s and, in many cases, are still in service today. One of the many...

Characterization of bridge foundations workshop report.

DOT National Transportation Integrated Search

2013-11-01

"In 2013, the Federal Highway Administration proposed a new research program for the characterization of bridge foundations. To narrow the focus and develop a research roadmap for the program, a workshop on Characterization of Bridge Foundations...

Compilation of accelerated bridge construction (ABC) bridges : final report.

DOT National Transportation Integrated Search

2016-01-01

Development of accelerated bridge construction (ABC) technologies has been occurring across the country, many times in : isolation. Although FHWA and others have worked to facilitate communication between these efforts, there was not a : comprehensiv...

Characterization of bridge foundations workshop report.

DOT National Transportation Integrated Search

2013-11-01

In 2013, the Federal Highway Administration proposed a new research program for the characterization of bridge : foundations. To narrow the focus and develop a research roadmap for the program, a workshop on : Characterization of Bridge Foundation...

Temporary bridge deck panels.

DOT National Transportation Integrated Search

2009-03-01

The research described here has resulted in the development of a simplistic and innovative interlocking : glulam bridge deck panel for use in temporary bridge deck applications. The key feature of this panel : system is the interlocking tongue and gr...

Developing county bridge repair and retrofit techniques.

DOT National Transportation Integrated Search

2013-08-01

Oklahoma rated first in the Nation in the percentage of bridges that are structurally deficient or : functionally obsolete. According to Federal Highway Administration data, Oklahoma uses : approximately 23,250 bridges maintained by state, County, Ci...

Bridge Scour Technology Transfer

DOT National Transportation Integrated Search

2018-01-24

Scour and flooding are the leading causes of bridge failures in the United States and therefore should be monitored. New applications of tools and technologies are being developed, tested, and implemented to reduce bridge scour risk. The National Coo...

Framework for a comprehensive bridge management and information system.

DOT National Transportation Integrated Search

2011-11-01

"The purpose of this research project was to provide a framework for the development of a Bridge : Management Information System (BMIS). Researchers developed a synthesis of current BMIS development : activities and identified sources of data availab...

Cross-bridge kinetics, cooperativity, and negatively strained cross- bridges in vertebrate smooth muscle. A laser-flash photolysis study

PubMed Central

1988-01-01

The effects of laser-flash photolytic release of ATP from caged ATP [P3- 1(2-nitrophenyl)ethyladenosine-5'-triphosphate] on stiffness and tension transients were studied in permeabilized guinea pig protal vein smooth muscle. During rigor, induced by removing ATP from the relaxed or contracting muscles, stiffness was greater than in relaxed muscle, and electron microscopy showed cross-bridges attached to actin filaments at an approximately 45 degree angle. In the absence of Ca2+, liberation of ATP (0.1-1 mM) into muscles in rigor caused relaxation, with kinetics indicating cooperative reattachment of some cross- bridges. Inorganic phosphate (Pi; 20 mM) accelerated relaxation. A rapid phase of force development, accompanied by a decline in stiffness and unaffected by 20 mM Pi, was observed upon liberation of ATP in muscles that were released by 0.5-1.0% just before the laser pulse. This force increment observed upon detachment suggests that the cross- bridges can bear a negative tension. The second-order rate constant for detachment of rigor cross-bridges by ATP, in the absence of Ca2+, was estimated to be 0.1-2.5 X 10(5) M-1s-1, which indicates that this reaction is too fast to limit the rate of ATP hydrolysis during physiological contractions. In the presence of Ca2+, force development occurred at a rate (0.4 s-1) similar to that of intact, electrically stimulated tissue. The rate of force development was an order of magnitude faster in muscles that had been thiophosphorylated with ATP gamma S before the photochemical liberation of ATP, which indicates that under physiological conditions, in non-thiophosphorylated muscles, light-chain phosphorylation, rather than intrinsic properties of the actomyosin cross-bridges, limits the rate of force development. The release of micromolar ATP or CTP from caged ATP or caged CTP caused force development of up to 40% of maximal active tension in the absence of Ca2+, consistent with cooperative attachment of cross-bridges. Cooperative reattachment of dephosphorylated cross-bridges may contribute to force maintenance at low energy cost and low cross-bridge cycling rates in smooth muscle. PMID:3373178

Connecticut permanent long-term bridge monitoring network, volume 2 : monitoring of curved post-tensioned concrete box-girder bridge : I-384 WB over I-84 in East Hartford (bridge #5686).

DOT National Transportation Integrated Search

2014-08-01

This report describes the instrumentation and data acquisition for a three-span continuous, curved post-tensioned box-girder : bridge in Connecticut. The computer-based remote monitoring system was developed to collect information on the deformations...

Connecticut permanent long-term bridge monitoring network, volume 6 : monitoring of a continuous plate girder bridge with load restrictions - Route 15 over the Housatonic River in Stratford (Bridge #761).

DOT National Transportation Integrated Search

2014-08-01

This report describes the instrumentation and data acquisition system for monitoring of a continuous span steel plate : girder bridge with a composite concrete deck located on a limited access highway. The monitoring system was : developed and instal...

Connecticut permanent long-term bridge monitoring network, volume 1 : monitoring of post-tensioned segmental concrete box-girder bridge - I-95 over the Connecticut River in Old Saybrook (bridge #6200).

DOT National Transportation Integrated Search

2014-08-01

This report describes the instrumentation and data acquisition for an eleven span segmental, post-tensioned : box-girder bridge in Connecticut. Based on a request from the designers, the computer-based remote : monitoring system was developed to coll...

Investigation of mechanistic deterioration modeling for bridge design and management.

DOT National Transportation Integrated Search

2017-04-01

The ongoing deterioration of highway bridges in Colorado dictates that an effective method for allocating limited management resources be developed. In order to predict bridge deterioration in advance, mechanistic models that analyze the physical pro...

6. BRIDGE LOOKING SOUTH FROM CROWN POINT STATE PARK SHOWING ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

6. BRIDGE LOOKING SOUTH FROM CROWN POINT STATE PARK SHOWING SURROUNDING DEVELOPMENT FROM CONSTRUCTION OF DAM - Columbia River Bridge at Grand Coulee Dam, Spanning Columbia River at State Route 155, Coulee Dam, Okanogan County, WA

Development of system reliability models for railway bridges.

DOT National Transportation Integrated Search

2012-07-01

Performance of the railway transportation network depends on the reliability of railway bridges, which can be affected by : various forms of deterioration and extreme environmental conditions. More than half of the railway bridges in US were : built ...

A forecast of bridge engineering, 1980-2000.

DOT National Transportation Integrated Search

1979-01-01

A three-pronged study was undertaken to forecast the nature of bridge engineering and construction for the years 1980 to 2000. First, the history of bridge engineering was explored to extrapolate likely future developments. Second, a detailed questio...

Vehicle Signal Analysis Using Artificial Neural Networks for a Bridge Weigh-in-Motion System

PubMed Central

Kim, Sungkon; Lee, Jungwhee; Park, Min-Seok; Jo, Byung-Wan

2009-01-01

This paper describes the procedures for development of signal analysis algorithms using artificial neural networks for Bridge Weigh-in-Motion (B-WIM) systems. Through the analysis procedure, the extraction of information concerning heavy traffic vehicles such as weight, speed, and number of axles from the time domain strain data of the B-WIM system was attempted. As one of the several possible pattern recognition techniques, an Artificial Neural Network (ANN) was employed since it could effectively include dynamic effects and bridge-vehicle interactions. A number of vehicle traveling experiments with sufficient load cases were executed on two different types of bridges, a simply supported pre-stressed concrete girder bridge and a cable-stayed bridge. Different types of WIM systems such as high-speed WIM or low-speed WIM were also utilized during the experiments for cross-checking and to validate the performance of the developed algorithms. PMID:22408487

Vehicle Signal Analysis Using Artificial Neural Networks for a Bridge Weigh-in-Motion System.

PubMed

Kim, Sungkon; Lee, Jungwhee; Park, Min-Seok; Jo, Byung-Wan

2009-01-01

This paper describes the procedures for development of signal analysis algorithms using artificial neural networks for Bridge Weigh-in-Motion (B-WIM) systems. Through the analysis procedure, the extraction of information concerning heavy traffic vehicles such as weight, speed, and number of axles from the time domain strain data of the B-WIM system was attempted. As one of the several possible pattern recognition techniques, an Artificial Neural Network (ANN) was employed since it could effectively include dynamic effects and bridge-vehicle interactions. A number of vehicle traveling experiments with sufficient load cases were executed on two different types of bridges, a simply supported pre-stressed concrete girder bridge and a cable-stayed bridge. Different types of WIM systems such as high-speed WIM or low-speed WIM were also utilized during the experiments for cross-checking and to validate the performance of the developed algorithms.

Bim from Laser SCANS… not Just for Buildings: Nurbs-Based Parametric Modeling of a Medieval Bridge

NASA Astrophysics Data System (ADS)

Barazzetti, L.; Banfi, F.; Brumana, R.; Previtali, M.; Roncoroni, F.

2016-06-01

Building Information Modelling is not limited to buildings. BIM technology includes civil infrastructures such as roads, dams, bridges, communications networks, water and wastewater networks and tunnels. This paper describes a novel methodology for the generation of a detailed BIM of a complex medieval bridge. The use of laser scans and images coupled with the development of algorithms able to handle irregular shapes allowed the creation of advanced parametric objects, which were assembled to obtain an accurate BIM. The lack of existing object libraries required the development of specific families for the different structural elements of the bridge. Finally, some applications aimed at assessing the stability and safety of the bridge are illustrated and discussed. The BIM of the bridge can incorporate this information towards a new "BIMonitoring" concept to preserve the geometric complexity provided by point clouds, obtaining a detailed BIM with object relationships and attributes.

Development of flexural vibration inspection techniques to rapidly assess the structural health of timber bridge systems

Treesearch

Xiping Wang; James P. Wacker; Robert J. Ross; Brian K. Brashaw; Robert Vatalaro

2005-01-01

This paper describes an effort to develop a global dynamic testing technique for evaluating the overall stiffness of timber bridge superstructures. A forced vibration method was used to measure the natural frequency of single-span timber bridges in the laboratory and field. An analytical model based on simple beam theory was proposed to represent the relationship...

Managing Florida's fracture critical bridges - phases 1 and 2 [summary].

DOT National Transportation Integrated Search

2016-05-01

Florida International University researchers : examined the possibility of removing twin steel : box-girder bridges from the list of fracture critical : structures. They studied the behavior of steel twin : box-girder bridges and developed a tool to ...

Synthesis of National and International Methodologies Used for Bridge Health Indices

DOT National Transportation Integrated Search

2016-05-01

Bridge performance measures are important components of any successful Bridge Management System. Different types of performance measures have been developed for various purposes. The types of performance measures are usually a reflection of an agency...

Investigating causes and determine repair needs to mitigate falling concrete from bridge decks.

DOT National Transportation Integrated Search

2012-09-01

This study developed a procedure to identify concrete bridge decks that are exhibiting the characteristics associated : with falling concrete. Field exploratory work on reinforced concrete bridge decks was supported by analytical and : laboratory inv...

Development of finite element models to predict dynamic bridge response.

DOT National Transportation Integrated Search

1997-10-01

Dynamic response has long been recognized as one of the significant factors affecting the service life and safety of bridge structures. Even though considerable research, both analytical and experimental, has been devoted to dynamic bridge behavior, ...

Precision monitoring of bridge deck curvature change during replacement.

DOT National Transportation Integrated Search

2016-05-01

This project was focused on development and deployment of a system for monitoring vertical : displacement in bridge decks and bridge spans. The system uses high precision wireless inclinometer : sensors to monitor inclinations at various points of a ...

Design considerations for bridge deck joint-sealing systems : summary report.

DOT National Transportation Integrated Search

1992-07-01

This is a report summary which summarizes a three year research effort related to the study of bridge deck expansion joint movements. Bridge deck expansion joint systems often develop serious problems requiring extensive and expensive maintenance. Th...

Development of a precast bridge deck overhang system

DOT National Transportation Integrated Search

2011-02-01

Prestressed-precast panels are commonly used at interior beams for bridge decks in Texas. The use of these panels can provide ease : of construction, sufficient capacity, and good economy for the construction of bridge decks in Texas. Current practic...

Abrasion-resistant concrete mix designs for precast bridge deck panels.

DOT National Transportation Integrated Search

2010-08-01

The report documents laboratory investigations undertaken to develop high performance concrete (HPC) for precast and pre-stressed bridge deck components that would reduce the life-cycle cost of bridges by improving the studded tire wear (abrasion) re...

ChemEd Bridges: Building Bridges between Two-Year College Chemistry Faculty and the National Chemical Education Community

ERIC Educational Resources Information Center

Ungar, Harry; Brown, David R.

2010-01-01

ChemEd Bridges is an NSF-funded project that provides career and professional development opportunities for chemistry faculty members who teach at two-year colleges (2YCs). We broaden the interests and the horizons of these faculty members by building bridges between them and the broader community of chemical educators. In particular, we have…

Connecticut permanent long-term bridge monitoring network, volume 5 : wireless monitoring of the hung span in a large truss bridge - I-95 NB over the Thames River in New London (bridge #3819).

DOT National Transportation Integrated Search

2014-08-01

This report describes the instrumentation and data acquisition for the center hung segment in the largest : truss bridge in Connecticut, located on the interstate system. The monitoring system was developed as a : joint effort between researchers at ...

Real-Time Bridge Monitoring : Developing Wireless Nanosensors to Monitor Structural Integrity

DOT National Transportation Integrated Search

2013-04-17

With steel bridges representing approximately 34 percent of the nearly 600,000 highway bridges in the United States, continual monitoring and early detection of deterioration in these structures is vital to prevent expensive repairs or catastrophic f...

Toward Successful Implementation of Prefabricated Deck Panels to Accelerate the Bridge Construction Process

DOT National Transportation Integrated Search

2016-08-01

The development of accelerated bridge construction (ABC) techniques and connection details has become a national research focus. With the aging of the interstate system and many bridges on key routes requiring extensive rehabilitation or replacement,...

Development of Predictive Model for bridge deck cracking : final report.

DOT National Transportation Integrated Search

2017-04-01

Early-age bridge deck cracking has been found to be a prevalent problem worldwide. While early-age : cracking will not cause failure of a bridge deck system independently, the penetration of deleterious substances : through the early-age cracks into ...

Research notes : thin polymer overlays on bridge decks.

DOT National Transportation Integrated Search

2007-11-01

Winters in Oregon are hard on our bridges. Vehicles with studded tires gouge the pavement and abrade the deck surface. This abrasion often leads to reduced skid resistance. As the bridge deck ages, cracks often develop. Deicing chemicals used in wint...

Development and performance evaluation of fiber reinforced polymer bridge : [technical summary].

DOT National Transportation Integrated Search

2014-03-01

Conventionally, highway bridge decks in the US are predominantly made of steel-reinforced concrete. However, repair and : maintenance costs of these bridges incurred at the federal and state levels are overwhelming. As a result, for many years, there...

Developing deterioration models for Wyoming bridges.

DOT National Transportation Integrated Search

2016-05-01

Deterioration models for the Wyoming Bridge Inventory were developed using both stochastic and deterministic models. : The selection of explanatory variables is investigated and a new method using LASSO regression to eliminate human bias : in explana...

Evaluation of bridge cables corrosion using acoustic emission technique

NASA Astrophysics Data System (ADS)

Li, Dongsheng; Ou, Jinping

2010-04-01

Owing to the nature of the stress, corrosion of bridge cable may result in catastrophic failure of the structure. However, using electrochemical techniques isn't fully efficient for the detection and control on line of the corrosion phenomenon. A non-destructive testing method based on acoustic emission technique monitoring bridge cable corrosion was explored. The steel strands were placed at room temperature in 5% NaCl solution. Acoustic emission (AE) characteristic parameters were recorded in the whole corrosion experiment process. Based on the plot of cumulated acoustic activity, the bridge cables corrosion included three stages. It can be clearly seen that different stages have different acoustic emission signal characteristics. The AE characteristic parameters would be increased with cables corrosion development. Finally, the bridge cables corrosion experiment with different stress state and different corrosion environment was performed. The results shows that stress magnitude only affects the bridge cable failure time, however, the AE characteristic parameters value has changed a little. It was verified that AE technique can be used to detect the bridge cable early corrosion, investigating corrosion developing trend, and in monitoring and evaluating corrosion damages.

A Bridge to Active Learning: A Summer Bridge Program Helps Students Maximize Their Active-Learning Experiences and the Active-Learning Experiences of Others.

PubMed

Cooper, Katelyn M; Ashley, Michael; Brownell, Sara E

2017-01-01

National calls to improve student academic success in college have sparked the development of bridge programs designed to help students transition from high school to college. We designed a 2-week Summer Bridge program that taught introductory biology content in an active-learning way. Through a set of exploratory interviews, we unexpectedly identified that Bridge students had developed sophisticated views of active learning, even though this was not an explicit goal of the program. We conducted an additional set of semistructured interviews that focused on active learning and compared the interviews of Bridge students with those from non-Bridge students who had been eligible for but did not participate in the program. We used the constant comparative method to identify themes from the interviews. We found that Bridge students perceived that, because they knew how to approach active learning and viewed it as important, they benefited more from active learning in introductory biology than non-Bridge students. Specifically, Bridge students seemed to be more aware of their own learning gains from participating in active learning. Compared with the majority of non-Bridge students, the majority of Bridge students described using a greater variety of strategies to maximize their experiences in active learning. Finally, in contrast to non-Bridge students, Bridge students indicated that they take an equitable approach to group work. These findings suggest that we may be able to prime students to maximize their own and other's experiences in active learning. © 2017 K. M. Cooper et al. CBE—Life Sciences Education © 2017 The American Society for Cell Biology. This article is distributed by The American Society for Cell Biology under license from the author(s). It is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

LIGHT BRIDGE IN A DEVELOPING ACTIVE REGION. I. OBSERVATION OF LIGHT BRIDGE AND ITS DYNAMIC ACTIVITY PHENOMENA

DOE Office of Scientific and Technical Information (OSTI.GOV)

Toriumi, Shin; Katsukawa, Yukio; Cheung, Mark C. M., E-mail: shin.toriumi@nao.ac.jp

Light bridges, the bright structures that divide the umbra of sunspots and pores into smaller pieces, are known to produce a wide variety of activity events in solar active regions (ARs). It is also known that the light bridges appear in the assembling process of nascent sunspots. The ultimate goal of this series of papers is to reveal the nature of light bridges in developing ARs and the occurrence of activity events associated with the light bridge structures from both observational and numerical approaches. In this first paper, exploiting the observational data obtained by Hinode, the Interface Region Imaging Spectrograph, andmore » the Solar Dynamics Observatory, we investigate the detailed structure of the light bridge in NOAA AR 11974 and its dynamic activity phenomena. As a result, we find that the light bridge has a weak, horizontal magnetic field, which is transported from the interior by a large-scale convective upflow and is surrounded by strong, vertical fields of adjacent pores. In the chromosphere above the bridge, a transient brightening occurs repeatedly and intermittently, followed by a recurrent dark surge ejection into higher altitudes. Our analysis indicates that the brightening is the plasma heating due to magnetic reconnection at lower altitudes, while the dark surge is the cool, dense plasma ejected from the reconnection region. From the observational results, we conclude that the dynamic activity observed in a light bridge structure such as chromospheric brightenings and dark surge ejections are driven by magnetoconvective evolution within the light bridge and its interaction with the surrounding magnetic fields.« less

Reliability-based criteria for load and resistance factor design code for wood bridges

Treesearch

Chris Eamon; Andrzej S. Nowak; Michael A. Ritter; Joe Murphy

2000-01-01

Recently AASHTO adopted a load and resistance factor design code for highway bridges. The new code provides a rational basis for the design of steel and concrete structures. However, the calibration was not done for wood bridges. Therefore, there is a need to fill this gap. The development of statistical models for wood bridge structures is discussed. Recent test...

A Bridge to Active Learning: A Summer Bridge Program Helps Students Maximize Their Active-Learning Experiences and the Active-Learning Experiences of Others

ERIC Educational Resources Information Center

Cooper, Katelyn M.; Ashley, Michael; Brownell, Sara E.

2017-01-01

National calls to improve student academic success in college have sparked the development of bridge programs designed to help students transition from high school to college. We designed a 2-week Summer Bridge program that taught introductory biology content in an active-learning way. Through a set of exploratory interviews, we unexpectedly…

The Maastricht-Duke bridge: An era of mentoring in clinical research - A model for mentoring in clinical research - A tribute to Dr. Galen Wagner.

PubMed

Meijs, Loek; Zusterzeel, Robbert; Wellens, Hein Jj; Gorgels, Anton Pm

With the passing of Dr. Galen Wagner, an exceptional collaboration between Maastricht University Medical Center, The Netherlands, and Duke Clinical Research Institute, USA, has come to an end. This article focuses on the background of what Galen coined the Maastricht-Duke bridge (MD-bridge), its merits, limitations and development throughout the years, and his special role. Between 2004 and 2015, 23 Maastricht University medical students and post-graduate students were enrolled in the 4-month research elective, mentored by Galen and the Maastricht co-mentor. They were asked to complete a survey about their MD-bridge experience. Sixteen out of the 23 students responded. None but 1 participant had prior research experience. Following their MD bridge-program most participants published 1 or more manuscripts and/or presented their research in an international setting. They felt they had full responsibility as a leader of their project with all participants developing meaningful skills useful in their current job. Fourteen out of 16 would recommend the MD-bridge experience to others. Participants considered the program of great value for their personal growth and independence, giving a feeling of achievement. In addition, for some participants it led to careers in foreign countries including medical practice and research, or obtaining PhDs. With Galen's impressive career of mentoring students, including the 23 MD-bridge participants, he has left behind an amazing concept of self-development in research and personal life. The successes of the MD-bridge prove that it is possible for students to be young investigators during or just after medical school with the potential to contribute to developing meaningful skills and noteworthy careers. Collaborations between international universities, such as the MD-bridge, are feasible and should be embraced by other institutions. Published by Elsevier Inc.

Evaluation of design methods to determine scour depths for bridge structures : [technical summary].

DOT National Transportation Integrated Search

2013-01-01

Scour of bridge foundations is the most common cause of bridge failures. The Federal Highway Administration : (FHWA) has developed a design method, HEC-18, for the state Departments of Transportation (DOTs) to evaluate : the scour potential of existi...

Development of FB-MultiPier dynamic vessel-collision analysis models, phase 2 : [summary].

DOT National Transportation Integrated Search

2014-07-01

When collisions between large vessels and bridge : supports occur, they can result in significant : damage to bridge and vessel. These collisions : are extremely hazardous, often taking lives on : the vessel and the bridge. Direct costs of repair : a...

Classification of longitudinal welds in an aluminum bridge deck.

DOT National Transportation Integrated Search

2000-01-01

An aluminum bridge deck (called ALUMADECK) has been developed by Reynolds Metal Company and is made of extruded aluminum sections welded together at the sides to form a bridge deck. The longitudinal welds used to connect the extrusions do not match a...

Bridges Structural Health Monitoring and Deterioration Detection Synthesis of Knowledge and Technology

DOT National Transportation Integrated Search

2011-09-01

Many U.S. bridges were built during the 1960s. Evaluating the structural condition of these bridges under todays traffic loads and safety expectations is difficult. This project is developing a practical program for structural health monitoring of...

Hybrid FRP-concrete bridge deck system final report I : development and system performance validation.

DOT National Transportation Integrated Search

2009-10-01

In this study, the concept of the hybrid FRP-concrete structural systems was applied to both bridge : superstructure and deck systems. Results from the both experimental and computational analysis for : both the hybrid bridge superstructure and deck ...

Feasibility of using shape memory alloys to develop self post-tensioned concrete bridge girders.

DOT National Transportation Integrated Search

2013-08-01

Post-tensioned (PT) structural elements are used quite often in bridges due to their ability to span long widths : economically while providing an aesthetically pleasing structure. PT systems are also preferred in bridge construction : because they g...

Load and resistance factor rating (LRFR) in New York State : volume II.

DOT National Transportation Integrated Search

2011-09-01

This report develops a Load and Resistance Factor Rating (NYS-LRFR) methodology : for New York bridges. The methodology is applicable for the rating of existing : bridges, the posting of under-strength bridges, and checking Permit trucks. The : propo...

Load and resistance factor rating (LRFR) in NYS : volume II final report.

DOT National Transportation Integrated Search

2011-09-01

This report develops a Load and Resistance Factor Rating (NYS-LRFR) methodology for New York bridges. The methodology is applicable for the rating of existing bridges, the posting of under-strength bridges, and checking Permit trucks. The proposed LR...

Load and resistance factor rating (LRFR) in NYS : volume I final report.

DOT National Transportation Integrated Search

2011-09-01

This report develops a Load and Resistance Factor Rating (NYS-LRFR) methodology for New York bridges. The methodology is applicable for the rating of existing bridges, the posting of under-strength bridges, and checking Permit trucks. The proposed LR...

Development of Degradation Rates for Various Bridge Types in the State of Ohio

DOT National Transportation Integrated Search

2011-03-01

The Ohio Department of Transportation (ODOT) maintains a Bridge Management System (BMS) which is : responsible for collecting and maintaining historical and longitudinal data by year for all the bridges in Ohio. The BMS aids : ODOT in tracking, desig...

Bridge maintenance program for the City of Columbia, Missouri : tech transfer summary.

DOT National Transportation Integrated Search

2017-09-01

The primary goal of this research was to extend the service lives of bridges in Columbia, Missouri. The overarching objective of the project was to develop bridge maintenance and preservation guidelines that focus on practical and implementable techn...

Development of degradation rates for various bridge types in the state of Ohio.

DOT National Transportation Integrated Search

2011-03-01

The Ohio Department of Transportation (ODOT) maintains a Bridge Management System (BMS) which is : responsible for collecting and maintaining historical and longitudinal data by year for all the bridges in Ohio. The BMS aids : ODOT in tracking, desig...

Effects of hauling timber, lignite coal, and coke fuel on Louisiana highways and bridges.

DOT National Transportation Integrated Search

2005-03-01

This study included the development of a methodology to assess the economic impact of overweight permitted vehicles hauling timber, lignite coal, and coke fuel on Louisiana highways and bridges. Researchers identified the highway routes and bridges b...

Volume balance and toxicity analysis of highway storm water discharge from Cross Lake Bridge.

DOT National Transportation Integrated Search

2009-06-01

The Cross Lake Bridge in Shreveport, Louisiana, spans Cross Lake that serves as the citys water supply. Concern : about accidents on the bridge contaminating the lake prompted the Louisiana Department of Transportation and : Development (LADOTD) t...

Volume balance and toxicity analysis of highway stormwater discharge from the cross lake bridge.

DOT National Transportation Integrated Search

2009-06-01

The Cross Lake Bridge in Shreveport, Louisiana, spans Cross Lake that serves as the citys water supply. Concern about accidents on the bridge contaminating the lake prompted the Louisiana Department of Transportation and Development (LADOTD) to co...

Developing cost effective plans for low volume bridges

DOT National Transportation Integrated Search

2006-09-01

There is currently an escalating concern across the state of Kansas with respect to the age : and condition of low volume bridges and methods available to modify or replace them. A : high percentage of low volume bridges in the state of Kansas requir...

Load and resistance factor rating (LRFR) in New York State : volume I.

DOT National Transportation Integrated Search

2011-09-01

This report develops a Load and Resistance Factor Rating (NYS-LRFR) methodology : for New York bridges. The methodology is applicable for the rating of existing : bridges, the posting of under-strength bridges, and checking Permit trucks. The : propo...

Research and development of weathering resistant bridge steel of Shougang

NASA Astrophysics Data System (ADS)

Yang, Yongda; Wang, Yanfeng; Huang, Leqing; Di, Guobiao; Ma, Changwen; Ma, Qingshen

2017-09-01

To introduce the composition design and mechanical properties and microstructure of the weathering bridge steel which would be used for bridge of Guanting reservoir. We adopt cyclic immersion corrosion test to study corrosion resistance difference of weathering bridge steel and common bridge steel. At the same corrosion time, the weight loss and corrosion rate of weathering bridge steel are lower than the common bridge steel's. Testing phase composition of rust layer by X-ray diffraction, two kinds of test steel's rust layer is mainly composed of Goethite and Fe3O4 and Fe2O3. At the same corrosion time, the percentage composition of goethite in rust layer of weathering bridge steel are significantly higher than common bridge steel's, the higher goethite content is, the compacter rust layer structure is. The compact rust layer would prevent the water and air passing the rust layer, and then preventing the further corrosion reaction, improving the corrosion resistance performance of weathering bridge steel.

Bridge Frost Prediction by Heat and Mass Transfer Methods

NASA Astrophysics Data System (ADS)

Greenfield, Tina M.; Takle, Eugene S.

2006-03-01

Frost on roadways and bridges can present hazardous conditions to motorists, particularly when it occurs in patches or on bridges when adjacent roadways are clear of frost. To minimize materials costs, vehicle corrosion, and negative environmental impacts, frost-suppression chemicals should be applied only when, where, and in the appropriate amounts needed to maintain roadways in a safe condition for motorists. Accurate forecasts of frost onset times, frost intensity, and frost disappearance (e.g., melting or sublimation) are needed to help roadway maintenance personnel decide when, where, and how much frost-suppression chemical to use. A finite-difference algorithm (BridgeT) has been developed that simulates vertical heat transfer in a bridge based on evolving meteorological conditions at its top and bottom as supplied by a weather forecast model. BridgeT simulates bridge temperatures at numerous points within the bridge (including its upper and lower surface) at each time step of the weather forecast model and calculates volume per unit area (i.e., depth) of deposited, melted, or sublimed frost. This model produces forecasts of bridge surface temperature, frost depth, and bridge condition (i.e., dry, wet, icy/snowy). Bridge frost predictions and bridge surface temperature are compared with observed and measured values to assess BridgeT's skill in forecasting bridge frost and associated conditions.

Evaluation of a pilot installation of an energy absorbing bridge rail.

DOT National Transportation Integrated Search

1978-01-01

A newly developed bridge rail which uses steel rings that collapse or deform to absorb the energy of an impacting vehicle was retrofitted to the concrete parapet of an existing interstate highway bridge. It was planned that the installation would be ...

Crash test and evaluation of the TxDOT T631 bridge rail.

DOT National Transportation Integrated Search

2014-01-01

In August 2010, Midwest Roadside Safety Facility (MwRSF) developed and crash tested a low-cost, energy-absorbing bridge rail for the Manual for Assessing Safety Hardware (MASH) TL-3 applications. This low-cost bridge rail was designed to be compatibl...

Developing cost effective plans for low volume bridges

DOT National Transportation Integrated Search

2006-09-01

There is currently an escalating concern across the state of Kansas with respect to the age and condition of low volume bridges and methods available to modify or replace them. A high percentage of low volume bridges in the state of Kansas require or...

Measurement of bridge deck layout prior to concrete placement : final report.

DOT National Transportation Integrated Search

2017-01-01

The main objective of this research was to develop a method of measuring and : producing as built bridge drawings. This was the first step in the feasibility : assessment for automated bridge deck paving. The research goes to show the : standard meth...

Development and validation of a sensor-based health monitoring model for the Parkview Bridge deck.

DOT National Transportation Integrated Search

2012-01-31

Accelerated bridge construction (ABC) using full-depth precast deck panels is an innovative technique that brings all : the benefits listed under ABC to full fruition. However, this technique needs to be evaluated and the performance of : the bridge ...

Wireless data collection retrievals of bridge inspection/management information.

DOT National Transportation Integrated Search

2017-02-28

To increase the efficiency and reliability of bridge inspections, MDOT contracted to have a 3D-model-based data entry application for mobile tablets developed to aid inspectors in the field. The 3D Bridge App is a mobile software tool designed to fac...

Evaluation and analysis of decked bulb T beam bridges.

DOT National Transportation Integrated Search

2015-03-01

A new corrosion-free decked bulb T beam bridge system has been developed to overcome some of the problems : associated with the construction of side-by-side box beam bridges such as the lack of inspection space between : beams and the longitudinal de...

Communication: An exact bound on the bridge function in integral equation theories.

PubMed

Kast, Stefan M; Tomazic, Daniel

2012-11-07

We show that the formal solution of the general closure relation occurring in Ornstein-Zernike-type integral equation theories in terms of the Lambert W function leads to an exact relation between the bridge function and correlation functions, most notably to an inequality that bounds possible bridge values. The analytical results are illustrated on the example of the Lennard-Jones fluid for which the exact bridge function is known from computer simulations under various conditions. The inequality has consequences for the development of bridge function models and rationalizes numerical convergence issues.

Development and simulation of microfluidic Wheatstone bridge for high-precision sensor

NASA Astrophysics Data System (ADS)

Shipulya, N. D.; Konakov, S. A.; Krzhizhanovskaya, V. V.

2016-08-01

In this work we present the results of analytical modeling and 3D computer simulation of microfluidic Wheatstone bridge, which is used for high-accuracy measurements and precision instruments. We propose and simulate a new method of a bridge balancing process by changing the microchannel geometry. This process is based on the “etching in microchannel” technology we developed earlier (doi:10.1088/1742-6596/681/1/012035). Our method ensures a precise control of the flow rate and flow direction in the bridge microchannel. The advantage of our approach is the ability to work without any control valves and other active electronic systems, which are usually used for bridge balancing. The geometrical configuration of microchannels was selected based on the analytical estimations. A detailed 3D numerical model was based on Navier-Stokes equations for a laminar fluid flow at low Reynolds numbers. We investigated the behavior of the Wheatstone bridge under different process conditions; found a relation between the channel resistance and flow rate through the bridge; and calculated the pressure drop across the system under different total flow rates and viscosities. Finally, we describe a high-precision microfluidic pressure sensor that employs the Wheatstone bridge and discuss other applications in complex precision microfluidic systems.

Environmental classification scheme for Pontis.

DOT National Transportation Integrated Search

1994-01-01

In an effort to comply with the federal mandate for bridge management systems, many states have chosen to implement an existing system rather than develop their own. One such system is Pontis, the network-level bridge management system developed thro...

Theory Development: A Bridge between Practice and Research

ERIC Educational Resources Information Center

Southern, Stephen; Devlin, James

2010-01-01

Theory development is an intentional process by which marriage and family counselors may bridge the gap between research and practice. The theory building process includes inductive and deductive forms of reasoning, qualitative and quantitative approaches to knowledge development, and diffusion of innovations. Grounded theory provides an…

Recent research and applications of numerical simulation for dynamic response of long-span bridges subjected to multiple loads.

PubMed

Chen, Zhiwei; Chen, Bo

2014-01-01

Many long-span bridges have been built throughout the world in recent years but they are often subject to multiple types of dynamic loads, especially those located in wind-prone regions and carrying both trains and road vehicles. To ensure the safety and functionality of these bridges, dynamic responses of long-span bridges are often required for bridge assessment. Given that there are several limitations for the assessment based on field measurement of dynamic responses, a promising approach is based on numerical simulation technologies. This paper provides a detailed review of key issues involved in dynamic response analysis of long-span multiload bridges based on numerical simulation technologies, including dynamic interactions between running trains and bridge, between running road vehicles and bridge, and between wind and bridge, and in the wind-vehicle-bridge coupled system. Then a comprehensive review is conducted for engineering applications of newly developed numerical simulation technologies to safety assessment of long-span bridges, such as assessment of fatigue damage and assessment under extreme events. Finally, the existing problems and promising research efforts for the numerical simulation technologies and their applications to assessment of long-span multiload bridges are explored.

Recent Research and Applications of Numerical Simulation for Dynamic Response of Long-Span Bridges Subjected to Multiple Loads

PubMed Central

Chen, Zhiwei; Chen, Bo

2014-01-01

Many long-span bridges have been built throughout the world in recent years but they are often subject to multiple types of dynamic loads, especially those located in wind-prone regions and carrying both trains and road vehicles. To ensure the safety and functionality of these bridges, dynamic responses of long-span bridges are often required for bridge assessment. Given that there are several limitations for the assessment based on field measurement of dynamic responses, a promising approach is based on numerical simulation technologies. This paper provides a detailed review of key issues involved in dynamic response analysis of long-span multiload bridges based on numerical simulation technologies, including dynamic interactions between running trains and bridge, between running road vehicles and bridge, and between wind and bridge, and in the wind-vehicle-bridge coupled system. Then a comprehensive review is conducted for engineering applications of newly developed numerical simulation technologies to safety assessment of long-span bridges, such as assessment of fatigue damage and assessment under extreme events. Finally, the existing problems and promising research efforts for the numerical simulation technologies and their applications to assessment of long-span multiload bridges are explored. PMID:25006597

Stress analysis of the haunch region in a rigid frame bridge.

DOT National Transportation Integrated Search

1977-01-01

The purpose of this study was to obtain an understanding of the behavior and stress distribution in the haunch region of a rigid frame highway bridge. A finite element model of the haunch of the bridge was developed to permit the prediction of stress...

Development and validation of a sensor-based health monitoring model for the Parkview Bridge deck : [appendices].

DOT National Transportation Integrated Search

2012-01-31

Accelerated bridge construction (ABC) using full-depth precast deck panels is an innovative technique that brings all the benefits listed under ABC to full fruition. However, this technique needs to be evaluated and the performance of the bridge need...

Bridge-in-a-Backpack(TM). Task 1 : investigation of span lengths up to 70 feet.

DOT National Transportation Integrated Search

2011-08-01

The Bridge-in-a-Backpack has previously been demonstrated with short spans. The first : constructed one, Neal Bridge in Pittsfield, Maine had a span of 34 feet. This task includes : research and development that demonstrates the technology can be ...

Economic impact of multi-span, prestressed concrete girder bridges designed as simple span versus continuous span : final report.

DOT National Transportation Integrated Search

2016-10-01

The objective of this study was to determine the economic impact of designing pre-tensioned prestressed concrete beam (PPCB) : bridges utilizing the continuity developed in the bridge deck as opposed to the current Iowa Department of Transportation (...

Development of degradation rates for various bridge types in the state of Ohio : executive summary report.

DOT National Transportation Integrated Search

2011-03-01

The Ohio Department of Transportation (ODOT) maintains a Bridge Management System (BMS) which is : responsible for collecting and maintaining historical and longitudinal data by year for all the bridges in : Ohio.BMS aids ODOT in tracking, design, pl...

Development of Degradation Rates for Various Bridge Types in the State of Ohio : Executive Summary Report

DOT National Transportation Integrated Search

2011-03-01

The Ohio Department of Transportation (ODOT) maintains a Bridge Management System (BMS) which is responsible for collecting and maintaining historical and longitudinal data by year for all the bridges in Ohio.BMS aids ODOT in tracking, design, planni...

Design, installation, and condition assessment of a concrete bridge deck constructed with ASTM A1035 CS no. 4 bars.

DOT National Transportation Integrated Search

2017-06-01

Recently developed corrosion-resistant reinforcing structural design guidelines were used to design, construct, and : assess a reinforced concrete bridge deck with high-strength ASTM A1035 CS steel bars. The bridge replacement is located : along the ...

Quantification of cracks in concrete bridge decks in Ohio District 3.

DOT National Transportation Integrated Search

2012-02-01

The development of cracks in reinforced bridge decks is a critical problem, not only in Ohio state, but the whole of United States. Many bridge decks constructed within the last 10 years in Ohio have already shown varying levels and patterns of crack...

Quantification of cracks in concrete bridge decks in Ohio district 3.

DOT National Transportation Integrated Search

2012-02-01

The development of cracks in reinforced bridge decks is a critical problem, not only in Ohio state, but the whole of United States. Many bridge decks constructed within the last 10 years in Ohio have already shown varying levels and patterns of crack...

Non-destructive inspection protocol for reinforced concrete barriers and bridge railings

NASA Astrophysics Data System (ADS)

Chintakunta, Satish R.; Boone, Shane D.

2014-02-01

Reinforced concrete highway barriers and bridge railings serve to prevent errant vehicles from departing the travel way at grade separations. Despite the important role that they play in maintaining safety and their ubiquitous nature, barrier inspection rarely moves beyond visual inspection. In August 2008, a tractor-trailer fatally departed William Preston Lane, Jr. Memorial Bridge after it dislodged a section of the bridge barrier. Investigations following the accident identified significant corrosion of the anchor bolts attaching the bridge railing to the bridge deck. As a result of the information gathered during its investigation of the accident, the National Transportation Safety Board (NTSB) made recommendations to the Federal Highway Administration concerning Non-Destructive Evaluation (NDE) of concrete bridge railings. The Center for nondestructive evaluation (NDE) at Turner Fairbank Highway Research Center in McLean, VA is currently evaluating feasibility of using four technologies - ground penetrating radar (GPR), ultrasonic pulse-echo, digital radiography and infrared thermal imaging methods to develop bridge inspection methods that augment visual inspections, offer reliable measurement techniques, and are practical, both in terms of time and cost, for field inspection work. Controlled samples containing predefined corrosion levels in reinforcing steel were embedded at barrier connection points for laboratory testing. All four NDE techniques were used in the initial phase I testing. An inspection protocol for detecting and measuring the corrosion of reinforced steel embedded in the anchorage system will be developed as part of phase II research. The identified technologies shall be further developed for field testing utilizing a structure with a barrier in good condition and a structure with a barrier in poor condition.

Development of a precast bent cap system

DOT National Transportation Integrated Search

2001-01-01

Improved speed of construction and economy can be achieved through the use of precast bridge substructures. As a step in the advancement of precast bridge substructures, a precast bent cap system is developed for nonseismic regions, including a desig...

Bridging Cultures with Classroom Strategies.

ERIC Educational Resources Information Center

Rothstein-Fisch, Carrie; Greenfield, Patricia M.; Trumbull, Elise

1999-01-01

Collectivism, stressing family members' interdependence, is common to Latino cultures. In contrast, schools foster independence and individual achievement. To help teachers understand assumptions underlying these different values, the authors developed the "Bridging Cultures Project" as a research-based professional-development program.…

Damage detection in bridges through fiber optic structural health monitoring

NASA Astrophysics Data System (ADS)

Doornink, J. D.; Phares, B. M.; Wipf, T. J.; Wood, D. L.

2006-10-01

A fiber optic structural health monitoring (SHM) system was developed and deployed by the Iowa State University (ISU) Bridge Engineering Center (BEC) to detect gradual or sudden damage in fracture-critical bridges (FCBs). The SHM system is trained with measured performance data, which are collected by fiber optic strain sensors to identify typical bridge behavior when subjected to ambient traffic loads. Structural responses deviating from the trained behavior are considered to be signs of structural damage or degradation and are identified through analytical procedures similar to control chart analyses used in statistical process control (SPC). The demonstration FCB SHM system was installed on the US Highway 30 bridge near Ames, IA, and utilizes 40 fiber bragg grating (FBG) sensors to continuously monitor the bridge response when subjected to ambient traffic loads. After the data is collected and processed, weekly evaluation reports are developed that summarize the continuous monitoring results. Through use of the evaluation reports, the bridge owner is able to identify and estimate the location and severity of the damage. The information presented herein includes an overview of the SHM components, results from laboratory and field validation testing on the system components, and samples of the reduced and analyzed data.

Development of a Computational Approach to Detect Instability and Incipient Motion of Large Riprap Rocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bojanowski, C.; Lottes, S. A.; Flora, K.

2017-08-01

Local scour at bridge piers is a potential safety hazard of major concern to transportation agencies. If it is determined that scour at bridge piers can adversely affect the stability of a bridge, scour countermeasures to protect the pier should be considered.

Design and Evaluation of Scour for Bridges Using HEC-18 (Volume 3 of 3).

DOT National Transportation Integrated Search

2017-07-04

The overall objective of this research is the development of a new approach for evaluating bridge scour for New Jersey's bridges on non-tidal waterways. The study commenced with a web-based survey of scour practice within the U.S. and a literature re...

Design and Evaluation of Scour for Bridges Using HEC-18 (Volume 1 of 3).

DOT National Transportation Integrated Search

2017-07-04

The overall objective of this research is the development of a new approach for evaluating bridge scour for New Jersey's bridges on non-tidal waterways. The study commenced with a web-based survey of scour practice within the U.S. and a literature re...

Structural load testing and flexure analysis of the Route 701 Bridge in Louisa County, Virginia : supplemental report.

DOT National Transportation Integrated Search

2006-01-01

A continuous slab bridge in Louisa County, Virginia, on Route 701 developed a planar horizontal crack along the length of all three spans. This project was designed to determine if the current 12-ton posted load restriction of the bridge (instituted ...

Economic impact of multi-span, prestressed concrete girder bridges designed as simple span versus continuous span : tech transfer summary.

DOT National Transportation Integrated Search

2016-10-01

The objective of this study was to determine the economic impact of : designing pre-tensioned prestressed concrete beam (PPCB) bridges : utilizing the continuity developed in the bridge deck as opposed to the : current Iowa Department of Transportati...

Field demonstration of new bridge approach slab designs and performance : [research project capsule].

DOT National Transportation Integrated Search

2008-10-01

A normal bridge approach slab in Louisiana is a reinforced concrete slab. It connects : the bridge deck to the adjacent paved roadway. Its intended functions are: : 1. To span the void that may develop below the slab due to soil erosion or : embankme...

Constitutive and numerical modeling of soil and soil-pile interaction for 3D applications and Kealakaha stream bridge case study.

DOT National Transportation Integrated Search

2011-12-01

This study is concerned with developing new modeling tools for predicting the response of the new Kealakaha : Stream Bridge to static and dynamic loads, including seismic shaking. The bridge will span 220 meters, with the : deck structure being curve...

Vehicular crash tests of the California ST-20 bridge rail.

DOT National Transportation Integrated Search

2004-07-01

Over the course of this project a see-through steel bridge rail (Type California ST-20) was developed and tested. The ST-20, as tested, is at the limits of meeting the NCHRP Report 3501 TL-4 test matrix. The bridge rail also met the requirements esta...

Repair of distortion-induced fatigue damage in bridge no. 135-87 (043SB and 044NB) using newly-developed strengthening schemes : summary.

DOT National Transportation Integrated Search

2016-08-01

A steel girder twin bridge structure located near Park City, Kansas, has experienced : extensive distortion-induced fatigue cracking in its web-gap regions. Due to : the bridges skewed, staggered configuration, the majority of these cracks have : ...

Pennsylvania hardwood timber bridges : field performance after 10 years

Treesearch

James P. Wacker; Carlito Calil

2004-01-01

Several hardwood demonstration timber bridges were built by the Pennsylvania Department of Transportation in the early nineteen nineties. These bridge superstructures are of the recently developed stress-laminated deck design-type using Red Oak lumber laminations that were pressure-treated with creosote preservatives. This paper will describe the data acquisition...

International opportunities resource guide for the transportation development industry : accessing tools to grow internationally

DOT National Transportation Integrated Search

1978-05-01

A large number of bridges on two-lane rural highways are narrow bridges. While there is no universally accepted definition of this type of bridge, it is generally considered to be one where the roadway and/or shoulders narrow significantly. It has be...

Developing a methodology to inspect and assess conditions of short span structures on county roads in Wyoming : [project brief].

DOT National Transportation Integrated Search

2015-12-01

Even though the FHWAs National Bridge Inspection Standards are a very comprehensive tool for : bridge inspection, they only apply to structures with spans of more than 20 feet. WYDOT inspects : these larger bridges on regular intervals, but there ...

Design and Evaluation of Scour for Bridges Using HEC-18 (Volume 2 of 3).

DOT National Transportation Integrated Search

2017-07-04

The overall objective of this research is the development of a new approach for evaluating bridge scour for New Jersey's bridges on non-tidal waterways. The study commenced with a web-based survey of scour practice within the U.S. and a literature re...

Structural load testing and flexure analysis of the Route 701 Bridge in Louisa County, Virginia.

DOT National Transportation Integrated Search

2004-01-01

A continuous slab bridge in Louisa County, Virginia, on Route 701 developed a planar horizontal crack along the length of all three spans. This project was designed to determine if the current load rating of the bridge could be raised and to document...

Advanced bridge safety initiative, task 1 : development of improved analytical load rating procedures for flat-slab concrete bridges - a thesis and guidelines.

DOT National Transportation Integrated Search

2010-01-01

Current AASHTO provisions for the conventional load rating of flat slab bridges rely on the equivalent strip method : of analysis for determining live load effects, this is generally regarded as overly conservative by many professional : engineers. A...

The South Carolina bridge-scour envelope curves

USGS Publications Warehouse

Benedict, Stephen T.; Feaster, Toby D.; Caldwell, Andral W.

2016-09-30

The U.S. Geological Survey, in cooperation with the South Carolina Department of Transportation, conducted a series of three field investigations to evaluate historical, riverine bridge scour in the Piedmont and Coastal Plain regions of South Carolina. These investigations included data collected at 231 riverine bridges, which lead to the development of bridge-scour envelope curves for clear-water and live-bed components of scour. The application and limitations of the South Carolina bridge-scour envelope curves were documented in four reports, each report addressing selected components of bridge scour. The current investigation (2016) synthesizes the findings of these previous reports into a guidance manual providing an integrated procedure for applying the envelope curves. Additionally, the investigation provides limited verification for selected bridge-scour envelope curves by comparing them to field data collected outside of South Carolina from previously published sources. Although the bridge-scour envelope curves have limitations, they are useful supplementary tools for assessing the potential for scour at riverine bridges in South Carolina.

Polyurethane foam infill for fiber-reinforced polymer (FRP) bridge deck panels.

DOT National Transportation Integrated Search

2014-05-01

The objective of the proposed research is to develop, test, and evaluate fiber-reinforced, polyurethane foams to replace the costly : honeycomb construction currently used to manufacture FRP bridge deck panels. The effort will focus on developing an ...

Development of a guideline for estimating tsunami forces On bridge superstructures.

DOT National Transportation Integrated Search

2011-10-01

"The Pacific Northwest is vulnerable to seismic events in the Cascadia Subduction Zone (CSZ) that could generate a : large tsunami that could devastate coastal infrastructure such as bridges. In this context, this paper describes the : development of...

Determination of brace forces caused by construction loads and wind loads during bridge construction.

DOT National Transportation Integrated Search

2014-04-01

The first objective of this study was to develop procedures for determining bracing forces during bridge construction. : Numerical finite element models and analysis techniques were developed for evaluating brace forces induced by construction loads ...

Formation of lamellar cross bridges in the annulus fibrosus of the intervertebral disc is a consequence of vascular regression.

PubMed

Smith, Lachlan J; Elliott, Dawn M

2011-05-01

Cross bridges are radial structures within the highly organized lamellar structure of the annulus fibrosus of the intervertebral disc that connect two or more non-consecutive lamellae. Their origin and function are unknown. During fetal development, blood vessels penetrate deep within the AF and recede during postnatal growth. We hypothesized that cross bridges are the pathways left by these receding blood vessels. Initially, the presence of cross bridges was confirmed in cadaveric human discs aged 25 and 53 years. Next, L1-L2 intervertebral discs (n=4) from sheep ranging in age from 75 days fetal gestation to adult were processed for paraffin histology. Mid-sagittal sections were immunostained for endothelial cell marker PECAM-1. The anterior and posterior AF were imaged using differential interference contrast microscopy, and the following parameters were quantified: total number of distinct lamellae, total number of cross bridges, percentage of cross bridges staining positive for PECAM-1, cross bridge penetration depth (% total lamellae), and PECAM-1 positive cross bridge penetration depth. Cross bridges were first observed at 100 days fetal gestation. The overall number peaked in neonates then remained relatively unchanged. The percentage of PECAM-1 positive cross bridges declined progressively from almost 100% at 100 days gestation to less than 10% in adults. Cross bridge penetration depth peaked in neonates then remained unchanged at subsequent ages. Depth of PECAM-1 positive cross bridges decreased progressively after birth. Findings were similar for both the anterior and posterior. The AF lamellar architecture is established early in development. It later becomes disrupted as a consequence of vascularization. Blood vessels then recede, perhaps due to increasing mechanical stresses in the surrounding matrix. In this study we present evidence that the pathways left by receding blood vessels remain as lamellar cross bridges. It is unclear whether the presence of cross bridges in the aging and degenerating intervertebral disc would be advantageous or detrimental, and this question should be addressed by future studies. Copyright © 2011 International Society of Matrix Biology. Published by Elsevier B.V. All rights reserved.

BIM authoring for an image-based bridge maintenance system of existing cable-supported bridges

NASA Astrophysics Data System (ADS)

Dang, N. S.; Shim, C. S.

2018-04-01

Infrastructure nowadays is increasingly become the main backbone for the metropolitan development in general. Along with the rise of new facilities, the demand in term of maintenance for the existing bridges is indispensable. Recently, the terminology of “preventive maintenance” is not unfamiliar with the engineer, literally is the use of a bridge maintenance system (BMS) based on a BIM-oriented model. In this paper, the process of generating a BMS based on BIM model is introduced in detail. Data management for this BMS is separated into two modules: site inspection system and information management system. The noteworthy aspect of this model lays on the closed and automatic process of “capture image, generate the technical damage report, and upload/feedback to the BMS” in real-time. A pilot BMS system for a cable-supported bridge is presented which showed a good performance and potential to further development of preventive maintenance.

Theoretical mechanics: crowd synchrony on the Millennium Bridge.

PubMed

Strogatz, Steven H; Abrams, Daniel M; McRobie, Allan; Eckhardt, Bruno; Ott, Edward

2005-11-03

Soon after the crowd streamed on to London's Millennium Bridge on the day it opened, the bridge started to sway from side to side: many pedestrians fell spontaneously into step with the bridge's vibrations, inadvertently amplifying them. Here we model this unexpected and now notorious phenomenon--which was not due to the bridge's innovative design as was first thought--by adapting ideas originally developed to describe the collective synchronization of biological oscillators such as neurons and fireflies. Our approach should help engineers to estimate the damping needed to stabilize other exceptionally crowded footbridges against synchronous lateral excitation by pedestrians.

Natural canopy bridges effectively mitigate tropical forest fragmentation for arboreal mammals.

PubMed

Gregory, Tremaine; Carrasco-Rueda, Farah; Alonso, Alfonso; Kolowski, Joseph; Deichmann, Jessica L

2017-06-20

Linear infrastructure development and resulting habitat fragmentation are expanding in Neotropical forests, and arboreal mammals may be disproportionately impacted by these linear habitat clearings. Maintaining canopy connectivity through preservation of connecting branches (i.e. natural canopy bridges) may help mitigate that impact. Using camera traps, we evaluated crossing rates of a pipeline right-of-way in a control area with no bridges and in a test area where 13 bridges were left by the pipeline construction company. Monitoring all canopy crossing points for a year (7,102 canopy camera nights), we confirmed bridge use by 25 mammal species from 12 families. With bridge use beginning immediately after exposure and increasing over time, use rates were over two orders of magnitude higher than on the ground. We also found a positive relationship between a bridge's use rate and the number of species that used it, suggesting well-used bridges benefit multiple species. Data suggest bridge use may be related to a combination of bridge branch connectivity, multiple connections, connectivity to adjacent forest, and foliage cover. Given the high use rate and minimal cost, we recommend all linear infrastructure projects in forests with arboreal mammal populations include canopy bridges.

A statistical model of operational impacts on the framework of the bridge crane

NASA Astrophysics Data System (ADS)

Antsev, V. Yu; Tolokonnikov, A. S.; Gorynin, A. D.; Reutov, A. A.

2017-02-01

The technical regulations of the Customs Union demands implementation of the risk analysis of the bridge cranes operation at their design stage. The statistical model has been developed for performance of random calculations of risks, allowing us to model possible operational influences on the bridge crane metal structure in their various combination. The statistical model is practically actualized in the software product automated calculation of risks of failure occurrence of bridge cranes.

Bridging the Gap between Academic Research and Regional Development in the Basque Country

ERIC Educational Resources Information Center

Karlsen, James; Larrea, Miren; Wilson, James R.; Aranguren, Mari Jose

2012-01-01

The discussion in this article focuses on how the gap between academic knowledge and regional development can be bridged, creating conditions for change processes between researchers and regional agents. Institutional entrepreneurs can create regional development organisations and research organisations, but in order to fulfil regional needs it is…

76 FR 72423 - Bridging the Idea Development Evaluation Assessment and Long-Term Initiative and Total Product...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-11-23

... DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration [Docket No. FDA-2011-N-0780] Bridging the Idea Development Evaluation Assessment and Long-Term Initiative and Total Product Life Cycle... Idea Development Evaluation Assessment and Long-Term Initiative and Total Product Life Cycle Approaches...

Bridge Building and Other Possible Metaphors for Patching over Discrepancies between Typical and Atypical Development

ERIC Educational Resources Information Center

Chandler, Michael

2016-01-01

The next several pages are intended as a "Commentary" on the six target articles bundled together as a Special Issue of the "Journal of Cognition and Development"--literature reviews and research reports all intended to "build bridges" between the study of cognitive development in typical and atypical populations.

Hydraulic modeling of flow impact on bridge structures: a case study on Citarum bridge

NASA Astrophysics Data System (ADS)

Siregar, R. I.

2018-02-01

Flood waves because of the rapid catchment response to high intense rainfall, breaches of flood defenses may induce huge impact forces on structures, causing structural damage or even failures. Overflowing stream that passes over the bridge, it means to discharge flood water level is smaller than the capacity of the river flow. In this study, the researches present the methodological approach of flood modeling on bridge structures. The amount of force that obtained because of the hydrostatic pressure received by the bridge at the time of the flood caused the bridge structure disrupted. This paper presents simulation of flow impact on bridge structures with some event flood conditions. Estimating the hydrostatic pressure developed new model components, to quantify the flow impact on structures. Flow parameters applied the model for analyzing, such as discharge, velocity, and water level or head that effect of bridge structures. The simulation will illustrate the capability of bridge structures with some event flood river and observe the behavior of the flow that occurred during the flood. Hydraulic flood modeling use HEC-RAS for simulation. This modeling will describe the impact on bridge structures. Based on the above modelling resulted, in 2008 has flood effect more than other years on the Citarum Bridge, because its flow overflow on the bridge.

Development of high-performance concrete mixtures for durable bridge decks in Montana using locally available materials.

DOT National Transportation Integrated Search

2005-03-01

"The Montana Department of Transportation (MDT) is performing research to develop a cost-effective, indigenous highperformance : concrete (HPC) for use in bridge deck applications. The investigation was divided into two tasks: 1) : identification of ...

Development Length for Headed Bars in Slab-Column Joints of RC Slab Bridges

DOT National Transportation Integrated Search

2015-12-04

In accordance with the Caltrans Seismic Design Criteria, the superstructure in a slab bridge should remain essentially elastic and only the pile extensions/columns are permitted to develop inelastic deformations during a seismic event. Hence, the lon...

Design and evaluation of a single-span bridge using ultra-high performance concrete.

DOT National Transportation Integrated Search

2009-09-01

"Research presented herein describes an application of a newly developed material called Ultra-High Performance Concrete (UHPC) to a : single-span bridge. The two primary objectives of this research were to develop a shear design procedure for possib...

Design and evaluation of a single-span bridge using ultra-high performance concrete.

DOT National Transportation Integrated Search

2009-09-01

Research presented herein describes an application of a newly developed material called Ultra-High Performance Concrete (UHPC) to a : single-span bridge. The two primary objectives of this research were to develop a shear design procedure for possibl...

Development of Secondary Route Bridge Design Plan Guides

DOT National Transportation Integrated Search

2018-03-03

The objective of this study is to develop a set of bridge plan guides for low-volume traffic roads. The purpose of the plans is to facilitate construction of new structures suitable for local agencies. The designs are to specifically address common l...

Implementation of a localized roughness specification for use on Louisiana bridges : research project capsule : technology transfer program.

DOT National Transportation Integrated Search

2016-10-01

The Louisiana Transportation Research Center has worked closely with the Bridge : Design section of the Louisiana Department of Transportation and Development : (DOTD) to develop a workable specification for standard and localized roughness : of brid...

Pilot project for maximum heat of mass concrete.

DOT National Transportation Integrated Search

2013-04-01

A 3-D finite element model was developed for prediction of early age behavior of mass concrete footing placed on a soil layer. Three bridge pier footings and one bridge pier cap in Florida were monitored for temperature development. The measured temp...

Standards for single span prefabricated bridges : phase I - concept development.

DOT National Transportation Integrated Search

2014-07-01

In coordination with a Technical Advisory Committee (TAC) consisting of County : Engineers and Iowa DOT representatives, the Iowa DOT has proposed to develop a set : of standards for a single span prefabricated bridge system for use on the local road...

Non-destructive inspection protocol for reinforced concrete barriers and bridge railings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chintakunta, Satish R.; Boone, Shane D.

Reinforced concrete highway barriers and bridge railings serve to prevent errant vehicles from departing the travel way at grade separations. Despite the important role that they play in maintaining safety and their ubiquitous nature, barrier inspection rarely moves beyond visual inspection. In August 2008, a tractor-trailer fatally departed William Preston Lane, Jr. Memorial Bridge after it dislodged a section of the bridge barrier. Investigations following the accident identified significant corrosion of the anchor bolts attaching the bridge railing to the bridge deck. As a result of the information gathered during its investigation of the accident, the National Transportation Safety Boardmore » (NTSB) made recommendations to the Federal Highway Administration concerning Non-Destructive Evaluation (NDE) of concrete bridge railings. The Center for nondestructive evaluation (NDE) at Turner Fairbank Highway Research Center in McLean, VA is currently evaluating feasibility of using four technologies - ground penetrating radar (GPR), ultrasonic pulse-echo, digital radiography and infrared thermal imaging methods to develop bridge inspection methods that augment visual inspections, offer reliable measurement techniques, and are practical, both in terms of time and cost, for field inspection work. Controlled samples containing predefined corrosion levels in reinforcing steel were embedded at barrier connection points for laboratory testing. All four NDE techniques were used in the initial phase I testing. An inspection protocol for detecting and measuring the corrosion of reinforced steel embedded in the anchorage system will be developed as part of phase II research. The identified technologies shall be further developed for field testing utilizing a structure with a barrier in good condition and a structure with a barrier in poor condition.« less

Analysis, prediction, and case studies of early-age cracking in bridge decks

NASA Astrophysics Data System (ADS)

ElSafty, Adel; Graeff, Matthew K.; El-Gharib, Georges; Abdel-Mohti, Ahmed; Mike Jackson, N.

2016-06-01

Early-age cracking can adversely affect strength, serviceability, and durability of concrete bridge decks. Early age is defined as the period after final setting, during which concrete properties change rapidly. Many factors can cause early-age bridge deck cracking including temperature change, hydration, plastic shrinkage, autogenous shrinkage, and drying shrinkage. The cracking may also increase the effect of freeze and thaw cycles and may lead to corrosion of reinforcement. This research paper presents an analysis of causes and factors affecting early-age cracking. It also provides a tool developed to predict the likelihood and initiation of early-age cracking of concrete bridge decks. Understanding the concrete properties is essential so that the developed tool can accurately model the mechanisms contributing to the cracking of concrete bridge decks. The user interface of the implemented computer Excel program enables the user to input the properties of the concrete being monitored. The research study and the developed spreadsheet were used to comprehensively investigate the issue of concrete deck cracking. The spreadsheet is designed to be a user-friendly calculation tool for concrete mixture proportioning, temperature prediction, thermal analysis, and tensile cracking prediction. The study also provides review and makes recommendations on the deck cracking based mainly on the Florida Department of Transportation specifications and Structures Design Guidelines, and Bridge Design Manuals of other states. The results were also compared with that of other commercially available software programs that predict early-age cracking in concrete slabs, concrete pavement, and reinforced concrete bridge decks. The outcome of this study can identify a set of recommendations to limit the deck cracking problem and maintain a longer service life of bridges.

Integrating Gender and Group Differences into Bridging Strategy

ERIC Educational Resources Information Center

Yilmaz, Serkan; Eryilmaz, Ali

2010-01-01

The main goal of this study was to integrate gender and group effect into bridging strategy in order to assess the effect of bridging analogy-based instruction on sophomore students' misconceptions in Newton's Third Law. Specifically, the authors developed and benefited from anchoring analogy diagnostic test to merge the effect of group and gender…

Development of wave and surge atlas for the design and protection of coastal bridges in south Louisiana : [tech summary].

DOT National Transportation Integrated Search

2015-02-01

The failures of highway bridges on the Gulf Coast seen in the aftermath of Hurricane Katrina in 2005 were unprecedented. : In the past four decades, wind waves accompanied by high surges from hurricanes have damaged a number of coastal : bridges alon...

Implementation project : strengthening a continuous steel girder bridge in Lakeport, Texas with post-installed shear connectors : Phase 1 : bridge strengthening design and load testing.

DOT National Transportation Integrated Search

2017-03-01

In Implementation Project 5-6719, a non-composite continuous steel girder bridge located in Lakeport, Texas will be strengthened using techniques developed in TxDOT Research Project 0-6719. This strengthening technique involves the use of post-instal...

Testing of New Bridge Rail and Transition Designs Vol. X APP.I; 42-in (1.07-m) Concrete Parapet Bridge Railing

DOT National Transportation Integrated Search

1997-06-01

This report presents the results of a State Planning and Research (SP&R) pooled-fund study to develop safer bridge rail and transition designs.This pooled-fund study was sponsored by the Federal Highway Administration, 23 States, and the District of ...

HIV/AIDS and the Holistic Personal Relevance Model: An Holistic Approach to Bridging the Development Divide

ERIC Educational Resources Information Center

Matroos, Sebastian; van Wyk, Barry

2005-01-01

This paper aims to develop a theoretical and practical framework for lifelong learning which will contribute to bridging the development divide, thus facilitating the implementation of the MDGs on both a global and personal level. We see this happening through the direct personal and professional involvement of development professionals (that is,…

Foot force models of crowd dynamics on a wobbly bridge

PubMed Central

Belykh, Igor; Jeter, Russell; Belykh, Vladimir

2017-01-01

Modern pedestrian and suspension bridges are designed using industry standard packages, yet disastrous resonant vibrations are observed, necessitating multimillion dollar repairs. Recent examples include pedestrian-induced vibrations during the opening of the Solférino Bridge in Paris in 1999 and the increased bouncing of the Squibb Park Bridge in Brooklyn in 2014. The most prominent example of an unstable lively bridge is the London Millennium Bridge, which started wobbling as a result of pedestrian-bridge interactions. Pedestrian phase locking due to footstep phase adjustment is suspected to be the main cause of its large lateral vibrations; however, its role in the initiation of wobbling was debated. We develop foot force models of pedestrians’ response to bridge motion and detailed, yet analytically tractable, models of crowd phase locking. We use biomechanically inspired models of crowd lateral movement to investigate to what degree pedestrian synchrony must be present for a bridge to wobble significantly and what is a critical crowd size. Our results can be used as a safety guideline for designing pedestrian bridges or limiting the maximum occupancy of an existing bridge. The pedestrian models can be used as “crash test dummies” when numerically probing a specific bridge design. This is particularly important because the U.S. code for designing pedestrian bridges does not contain explicit guidelines that account for the collective pedestrian behavior. PMID:29296679

Foot force models of crowd dynamics on a wobbly bridge.

PubMed

Belykh, Igor; Jeter, Russell; Belykh, Vladimir

2017-11-01

Modern pedestrian and suspension bridges are designed using industry standard packages, yet disastrous resonant vibrations are observed, necessitating multimillion dollar repairs. Recent examples include pedestrian-induced vibrations during the opening of the Solférino Bridge in Paris in 1999 and the increased bouncing of the Squibb Park Bridge in Brooklyn in 2014. The most prominent example of an unstable lively bridge is the London Millennium Bridge, which started wobbling as a result of pedestrian-bridge interactions. Pedestrian phase locking due to footstep phase adjustment is suspected to be the main cause of its large lateral vibrations; however, its role in the initiation of wobbling was debated. We develop foot force models of pedestrians' response to bridge motion and detailed, yet analytically tractable, models of crowd phase locking. We use biomechanically inspired models of crowd lateral movement to investigate to what degree pedestrian synchrony must be present for a bridge to wobble significantly and what is a critical crowd size. Our results can be used as a safety guideline for designing pedestrian bridges or limiting the maximum occupancy of an existing bridge. The pedestrian models can be used as "crash test dummies" when numerically probing a specific bridge design. This is particularly important because the U.S. code for designing pedestrian bridges does not contain explicit guidelines that account for the collective pedestrian behavior.

Assessment of bridge abutment scour and sediment transport under various flow conditions

NASA Astrophysics Data System (ADS)

Gilja, Gordon; Valyrakis, Manousos; Michalis, Panagiotis; Bekić, Damir; Kuspilić, Neven; McKeogh, Eamon

2017-04-01

Safety of bridges over watercourses can be compromised by flow characteristics and bridge hydraulics. Scour process around bridge foundations can develop rapidly during low-recurrence interval floods when structural elements are exposed to increased flows. Variations in riverbed geometry, as a result of sediment removal and deposition processes, can increase flood-induced hazard at bridge sites with catastrophic failures and destructive consequences for civil infrastructure. The quantification of flood induced hazard on bridge safety generally involves coupled hydrodynamic and sediment transport models (i.e. 2D numerical or physical models) for a range of hydrological events covering both high and low flows. Modelled boundary conditions are usually estimated for their probability of occurrence using frequency analysis of long-term recordings at gauging stations. At smaller rivers gauging station records are scarce, especially in upper courses of rivers where weirs, drops and rapids are common elements of river bathymetry. As a result, boundary conditions that accurately represent flow patterns on modelled river reach cannot be often reliably acquired. Sediment transport process is also more complicated to describe due to its complexity and dependence to local flow field making scour hazard assessment a particularly challenging issue. This study investigates the influence of flow characteristics to the development of scour and sedimentation processes around bridge abutments of a single span masonry arch bridge in south Ireland. The impact of downstream weirs on bridge hydraulics through variation of downstream model domain type is also considered in this study. The numerical model is established based on detailed bathymetry data surveyed along a rectangular grid of 50cm spacing. Acquired data also consist of riverbed morphology and water level variations which are monitored continuously on bridge site. The obtained data are then used to compare and calibrate numerical models for several flood scenarios. The determination of the boundary conditions is followed by physical modelling to investigate the development of scour around bridge elements. The comparison of surveyed data with the obtained numerical and physical modelling results provide an insight of various flow patterns and their influence on riverbed morphology. This can deliver important information needed for assessment of structural risk associated with flood events. Acknowledgement: The authors wish to acknowledge the financial support of the European Commission, through the Marie Curie action Industry-Academia Partnership and Pathways Network BRIDGE SMS (Intelligent Bridge Assessment Maintenance and Management System) - FP7-People-2013-IAPP- 612517.

Development and validation of deterioration models for concrete bridge decks - phase 2 : mechanics-based degradation models.

DOT National Transportation Integrated Search

2013-06-01

This report summarizes a research project aimed at developing degradation models for bridge decks in the state of Michigan based on durability mechanics. A probabilistic framework to implement local-level mechanistic-based models for predicting the c...

Research on Swivel Construction Technology of 22,400 Tons in Zoucheng Thirty Meter Bridge

NASA Astrophysics Data System (ADS)

Han, Jun; Benlin, Xiao

2018-05-01

In recent years, with the rapid development of highways and railways in our country, there have been many new bridges that need to cross the existing routes. If the conventional construction methods are used, the existing traffic will be affected and the traffic will be built above the busy traffic lines, so there is a big security risk, the construction methods must be improved and innovated. In this paper, it intends to research and develop some key technologies of swivel construction. According to the construction features to use finite element method of swivel cable-stayed bridge to analyse the cable-stayed bridge . The swivel construction process is carried out to solve the technical problems and difficulties in the construction.

Effect of mechanical degradation of laminated elastomeric bearings and shear keys upon seismic behaviors of small-to-medium-span highway bridges in transverse direction

NASA Astrophysics Data System (ADS)

Wu, Gang; Wang, Kehai; Zhang, Panpan; Lu, Guanya

2018-01-01

Laminated elastomeric bearings have been widely used for small-to-medium-span highway bridges in China, in which concrete shear keys are set transversely to prohibit large girder displacement. To evaluate bridge seismic responses more accurately, proper analytical models of bearings and shear keys should be developed. Based on a series of cyclic loading experiments and analyses, rational analytical models of laminated elastomeric bearings and shear keys, which can consider mechanical degradation, were developed. The effect of the mechanical degradation was investigated by examining the seismic response of a small-to-medium-span bridge in the transverse direction under a wide range of peak ground accelerations (PGA). The damage mechanism for small-to-medium-span highway bridges was determined, which can explain the seismic damage investigation during earthquakes in recent years. The experimental results show that the mechanical properties of laminated elastomeric bearings will degrade due to friction sliding, but the degree of decrease is dependent upon the influencing parameters. It can be concluded that the mechanical degradation of laminated elastomeric bearings and shear keys play an important role in the seismic response of bridges. The degradation of mechanical properties of laminated elastomeric bearings and shear keys should be included to evaluate more precise bridge seismic performance.

Software user's guide for determining the Pennsylvania scour critical indicator code and streambed scour assessment rating for roadway bridges

USGS Publications Warehouse

Henneberg, M.F.; Strause, J.L.

2002-01-01

This report presents the instructions required to use the Scour Critical Bridge Indicator (SCBI) Code and Scour Assessment Rating (SAR) calculator developed by the Pennsylvania Department of Transportation (PennDOT) and the U.S. Geological Survey to identify Pennsylvania bridges with excessive scour conditions or a high potential for scour. Use of the calculator will enable PennDOT bridge personnel to quickly calculate these scour indices if site conditions change, new bridges are constructed, or new information needs to be included. Both indices are calculated for a bridge simultaneously because they must be used together to be interpreted accurately. The SCBI Code and SAR calculator program is run by a World Wide Web browser from a remote computer. The user can 1) add additional scenarios for bridges in the SCBI Code and SAR calculator database or 2) enter data for new bridges and run the program to calculate the SCBI Code and calculate the SAR. The calculator program allows the user to print the results and to save multiple scenarios for a bridge.

An impedance bridge measuring the capacitance ratio in the high frequency range up to 1 MHz

NASA Astrophysics Data System (ADS)

Bee Kim, Dan; Kew Lee, Hyung; Kim, Wan-Seop

2017-02-01

This paper describes a 2-terminal-pair impedance bridge, measuring the capacitance ratio in the high frequency range up to 1 MHz. The bridge was configured with two voltage sources and a phase control unit which enabled the bridge balance by synchronizing the voltage sources with an enhanced phase resolution. Without employing the transformers such as inductive voltage divider, injection and detection transformers, etc, the bridge system is quite simple to set up, and the balance procedure is quick and easy. Using this dual-source coaxial bridge, the 1:1 and 10:1 capacitance ratios were measured with 1 pF-1 nF capacitors in the frequency range from 1 kHz to 1 MHz. The measurement values obtained by the dual-source bridge were then compared with reference values measured using a commercial precision capacitance bridge of AH2700A, the Z-matrix method developed by ourselves, and the 4-terminal-pair coaxial bridge by the Czech Metrological Institute. All the measurements agreed within the reference uncertainty range of an order of 10-6-10-5, proving the bridge ability as a trustworthy tool for measuring the capacitance ratio in the high frequency range.

Symmetric and asymmetric capillary bridges between a rough surface and a parallel surface.

PubMed

Wang, Yongxin; Michielsen, Stephen; Lee, Hoon Joo

2013-09-03

Although the formation of a capillary bridge between two parallel surfaces has been extensively studied, the majority of research has described only symmetric capillary bridges between two smooth surfaces. In this work, an instrument was built to form a capillary bridge by squeezing a liquid drop on one surface with another surface. An analytical solution that describes the shape of symmetric capillary bridges joining two smooth surfaces has been extended to bridges that are asymmetric about the midplane and to rough surfaces. The solution, given by elliptical integrals of the first and second kind, is consistent with a constant Laplace pressure over the entire surface and has been verified for water, Kaydol, and dodecane drops forming symmetric and asymmetric bridges between parallel smooth surfaces. This solution has been applied to asymmetric capillary bridges between a smooth surface and a rough fabric surface as well as symmetric bridges between two rough surfaces. These solutions have been experimentally verified, and good agreement has been found between predicted and experimental profiles for small drops where the effect of gravity is negligible. Finally, a protocol for determining the profile from the volume and height of the capillary bridge has been developed and experimentally verified.

Dynamics of liquid bridges inside microchannels subject to pure oscillatory flows

NASA Astrophysics Data System (ADS)

Ahmadlouydarab, Majid; Azaiez, Jalel; Chen, Zhangxin

2014-11-01

We report on 2D simulations of liquid bridges' dynamics in microchannels of uniform wettability and subject to external oscillatory flows. The flow equations were solved using the Cahn-Hilliard diffuse-interface formulation and the finite element method with unstructured grid. It was found that regardless of the wettability properties of the microchannel walls, there is a critical frequency above which the bridge shows perpetual periodic oscillatory motion. Below that critical frequency, the liquid bridge ruptures when the channel walls are philic and detaches from the surface when they are phobic. This critical frequency depends on the viscosity ratio, oscillation amplitude and geometric aspect ratio of the bridge. It was also found that the flow velocity is out of phase with the footprint/throat lengths and that the latter two show a phase difference. These differences were explained in terms of the motion of the two contact lines on the substrates and the deformation of the fluid-fluid interfaces. To characterize the behavior of the liquid bridge, two quantitative parameters; the liquid bridge-solid interfacial length and the length of the throat of the liquid bridge were used. Variations of the interfacial morphology development of the bridge were analyzed to understand the bridge response.

Nondestructive assessment of timber bridges using a vibration-based method

Treesearch

Xiping Wang; James P. Wacker; Robert J. Ross; Brian K. Brashaw

2005-01-01

This paper describes an effort to develop a global dynamic testing technique for evaluating the overall stiffness of timber bridge superstructures. A forced vibration method was used to measure the natural frequency of single-span timber bridges in the laboratory and field. An analytical model based on simple beam theory was proposed to represent the relationship...

Bridging the Gap: A Research-Based Approach for Teaching Interdisciplinary Science to Undergraduate Freshman Students

ERIC Educational Resources Information Center

Sales, Jessica; Comeau, Dawn; Liddle, Kathleen; Khanna, Nikki; Perrone, Lisa; Palmer, Katrina; Lynn, David

2006-01-01

A new program, On Recent Discoveries by Emory Researchers (ORDER), has been developed as a bridge across the ever-widening gap between graduate and undergraduate education in the sciences. This bridge is created by merging the needs of graduate/postdoctoral students to educate more interdisciplinary scholars about their research discoveries with…

Bridging Geography and Education for Sustainable Development: A Korean Example

ERIC Educational Resources Information Center

Gress, Douglas R.; Tschapka, Johannes M.

2017-01-01

There is an apparent disconnect between geography and education for sustainable development (ESD), with geography underrepresented in publications and curricula related to sustainability though the discipline embraces the need to foment positive change. To bridge this schism, this article introduces advances in education for sustainable…

BRIDG: a domain information model for translational and clinical protocol-driven research.

PubMed

Becnel, Lauren B; Hastak, Smita; Ver Hoef, Wendy; Milius, Robert P; Slack, MaryAnn; Wold, Diane; Glickman, Michael L; Brodsky, Boris; Jaffe, Charles; Kush, Rebecca; Helton, Edward

2017-09-01

It is critical to integrate and analyze data from biological, translational, and clinical studies with data from health systems; however, electronic artifacts are stored in thousands of disparate systems that are often unable to readily exchange data. To facilitate meaningful data exchange, a model that presents a common understanding of biomedical research concepts and their relationships with health care semantics is required. The Biomedical Research Integrated Domain Group (BRIDG) domain information model fulfills this need. Software systems created from BRIDG have shared meaning "baked in," enabling interoperability among disparate systems. For nearly 10 years, the Clinical Data Standards Interchange Consortium, the National Cancer Institute, the US Food and Drug Administration, and Health Level 7 International have been key stakeholders in developing BRIDG. BRIDG is an open-source Unified Modeling Language-class model developed through use cases and harmonization with other models. With its 4+ releases, BRIDG includes clinical and now translational research concepts in its Common, Protocol Representation, Study Conduct, Adverse Events, Regulatory, Statistical Analysis, Experiment, Biospecimen, and Molecular Biology subdomains. The model is a Clinical Data Standards Interchange Consortium, Health Level 7 International, and International Standards Organization standard that has been utilized in national and international standards-based software development projects. It will continue to mature and evolve in the areas of clinical imaging, pathology, ontology, and vocabulary support. BRIDG 4.1.1 and prior releases are freely available at https://bridgmodel.nci.nih.gov . © The Author 2017. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Wireless sensing system for bridge condition assessment and health monitoring

NASA Astrophysics Data System (ADS)

Gangone, Michael V.; Whelan, Matthew J.; Janoyan, Kerop D.

2009-03-01

Discussed in this paper is the deployment of a universal and low-cost dense wireless sensor system for structural monitoring, load rating and condition assessment of bridges. The wireless sensor system developed is designed specifically for diagnostic bridge monitoring, providing independent conditioning for both accelerometers and strain transducers in addition to high-rate wireless data transmission. The system was field deployed on a three span simply supported bridge superstructure, where strain and acceleration measurements were obtained simultaneously and in realtime at critical locations under several loading conditions, providing reliable quantitative information as to the actual performance level of the bridge. Monitoring was also conducted as the bridge was subjected to various controlled damage scenarios on the final day of testing. Select cases of detected damage using strain and modal based analysis are presented.

Bridge-in-a-backpack(TM) task 4 : development of improved arch concrete mix to facilitate field use.

DOT National Transportation Integrated Search

2016-02-01

This report includes fulfillment of Task 4 of a multi-task contract to further enhance concrete filled FRP tubes, or : the Bridge in a Backpack. Task 4 investigates the development of improved concrete mixes for filling the FRP : tubes. : One critica...

Bridge-in-a-Backpack(TM) task 4 : development of improved arch concrete mix to facilitate field use.

DOT National Transportation Integrated Search

2016-02-01

This report includes fulfillment of Task 4 of a multi-task contract to further enhance concrete filled FRP tubes, or : the Bridge in a Backpack. Task 4 investigates the development of improved concrete mixes for filling the FRP : tubes. : One critica...

Bridges. A Physics Unit for 14/15 Year Old Students. Experimental Edition.

ERIC Educational Resources Information Center

Utrecht State Univ., (Netherlands).

Bridges and similar constructions are highlighted in this book of guided lessons and activities for secondary school physics students. This program was developed by the Physics Curriculum Development Project under the auspices of the Physics Curriculum Innovation Committee. Contents include: (1) "Introduction" (presenting a rationale for…

Development of a smart timber bridge - a five-year plan

Treesearch

Brent M. Phares; Terry J. Wipf; Ursula Deza; James P. Wacker

2011-01-01

This paper outlines a 5-year research plan for the development of a structural health monitoring system for timber bridges. A series of studies identify and evaluate various sensing technologies for measurement of structural adequacy and/or deterioration parameters. The overall goal is to develop a turn-key system to analyze, monitor, and report on the performance and...

A Sterile 20 Family Kinase and Its Co-factor CCM-3 Regulate Contractile Ring Proteins on Germline Intercellular Bridges.

PubMed

Rehain-Bell, Kathryn; Love, Andrew; Werner, Michael E; MacLeod, Ian; Yates, John R; Maddox, Amy Shaub

2017-03-20

Germ cells in most animals are connected by intercellular bridges, actin-based rings that form stable cytoplasmic connections between cells promoting communication and coordination [1]. Moreover, these connections are required for fertility [1, 2]. Intercellular bridges are proposed to arise from stabilization of the cytokinetic ring during incomplete cytokinesis [1]. Paradoxically, proteins that promote closure of cytokinetic rings are enriched on stably open intercellular bridges [1, 3, 4]. Given this inconsistency, the mechanism of intercellular bridge stabilization is unclear. Here, we used the C. elegans germline as a model for identifying molecular mechanisms regulating intercellular bridges. We report that bridges are actually highly dynamic, changing size at precise times during germ cell development. We focused on the regulation of bridge stability by anillins, key regulators of cytokinetic rings and cytoplasmic bridges [1, 4-7]. We identified GCK-1, a conserved serine/threonine kinase [8], as a putative novel anillin interactor. GCK-1 works together with CCM-3, a known binding partner [9], to promote intercellular bridge stability and limit localization of both canonical anillin and non-muscle myosin II (NMM-II) to intercellular bridges. Additionally, we found that a shorter anillin, known to stabilize bridges [4, 7], also regulates NMM-II levels at bridges. Consistent with these results, negative regulators of NMM-II stabilize intercellular bridges in the Drosophila egg chamber [10, 11]. Together with our findings, this suggests that tuning of myosin levels is a conserved mechanism for the stabilization of intercellular bridges that can occur by diverse molecular mechanisms. Copyright © 2017 Elsevier Ltd. All rights reserved.

Development of a six-year research needs assessment for timber transportation structures

Treesearch

Terry J. Wipf; Michael A. Ritter; Sheila Rimal Duwadi; Russell C. Moody

1993-01-01

A timber bridge, once a thing of the past, is now becoming a thing of the present. Interest in timber bridges and other transportation structures has been rapidly increasing. Much of this is due to new technologies in design and construction as well as advances in material manufacturing and presevative treatments. Although timber bridges and other transportation...

Nondestructive assessment of single-span timber bridges using a vibration- based method

Treesearch

Xiping Wang; James P. Wacker; Angus M. Morison; John W. Forsman; John R. Erickson; Robert J. Ross

2005-01-01

This paper describes an effort to develop a global dynamic testing technique for evaluating the overall stiffness of timber bridge superstructures. A forced vibration method was used to measure the natural frequency of single-span timber bridges in the laboratory and field. An analytical model based on simple beam theory was proposed to represent the relationship...

The Development of Maritime English Learning Model Using Authentic Assessment Based Bridge Simulator in Merchant Marine Polytechnic, Makassar

ERIC Educational Resources Information Center

Fauzi, Ahmad; Bundu, Patta; Tahmir, Suradi

2016-01-01

Bridge simulator constitutes a very fundamental and vital tool to trigger and ensure that seamen or seafarers possess the standardized competence required. By using the bridge simulator technique, a reality based study can be presented easily and delivered to the students in ongoing basis to their classroom or study place. Afterwards, the validity…

Health Monitoring and Evaluation of Long-Span Bridges Based on Sensing and Data Analysis: A Survey

PubMed Central

Zhou, Jianting; Li, Xiaogang; Xia, Runchuan; Yang, Jun; Zhang, Hong

2017-01-01

Aimed at the health monitoring and evaluation of bridges based on sensing technology, the monitoring contents of different structural types of long-span bridges were defined. Then, the definition, classification, selection principle, and installation requirements of the sensors were summarized. The concept was proposed that new adaptable long-life sensors could be developed by new theories and new effects. The principle and methods to select controlled sections and optimize the layout design of measuring points were illustrated. The functional requirements were elaborated on about the acquisition, transmission, processing, and management of sensing information. Some advanced concepts about the method of bridge safety evaluation were demonstrated and technology bottlenecks in the current safety evaluation were also put forward. Ultimately, combined with engineering practices, an application was carried out. The results showed that new, intelligent, and reliable sensor technology would be one of the main future development directions in the long-span bridge health monitoring and evaluation field. Also, it was imperative to optimize the design of the health monitoring system and realize its standardization. Moreover, it is a heavy responsibility to explore new thoughts and new concepts regarding practical bridge safety and evaluation technology. PMID:28300785

Salt bridges: geometrically specific, designable interactions.

PubMed

Donald, Jason E; Kulp, Daniel W; DeGrado, William F

2011-03-01

Salt bridges occur frequently in proteins, providing conformational specificity and contributing to molecular recognition and catalysis. We present a comprehensive analysis of these interactions in protein structures by surveying a large database of protein structures. Salt bridges between Asp or Glu and His, Arg, or Lys display extremely well-defined geometric preferences. Several previously observed preferences are confirmed, and others that were previously unrecognized are discovered. Salt bridges are explored for their preferences for different separations in sequence and in space, geometric preferences within proteins and at protein-protein interfaces, co-operativity in networked salt bridges, inclusion within metal-binding sites, preference for acidic electrons, apparent conformational side chain entropy reduction on formation, and degree of burial. Salt bridges occur far more frequently between residues at close than distant sequence separations, but, at close distances, there remain strong preferences for salt bridges at specific separations. Specific types of complex salt bridges, involving three or more members, are also discovered. As we observe a strong relationship between the propensity to form a salt bridge and the placement of salt-bridging residues in protein sequences, we discuss the role that salt bridges might play in kinetically influencing protein folding and thermodynamically stabilizing the native conformation. We also develop a quantitative method to select appropriate crystal structure resolution and B-factor cutoffs. Detailed knowledge of these geometric and sequence dependences should aid de novo design and prediction algorithms. Copyright © 2010 Wiley-Liss, Inc.

Estimation of Bridge Height over Water from Polarimetric SAR Image Data Using Mapping and Projection Algorithm and De-Orientation Theory

NASA Astrophysics Data System (ADS)

Wang, Haipeng; Xu, Feng; Jin, Ya-Qiu; Ouchi, Kazuo

An inversion method of bridge height over water by polarimetric synthetic aperture radar (SAR) is developed. A geometric ray description to illustrate scattering mechanism of a bridge over water surface is identified by polarimetric image analysis. Using the mapping and projecting algorithm, a polarimetric SAR image of a bridge model is first simulated and shows that scattering from a bridge over water can be identified by three strip lines corresponding to single-, double-, and triple-order scattering, respectively. A set of polarimetric parameters based on the de-orientation theory is applied to analysis of three types scattering, and the thinning-clustering algorithm and Hough transform are then employed to locate the image positions of these strip lines. These lines are used to invert the bridge height. Fully polarimetric image data of airborne Pi-SAR at X-band are applied to inversion of the height and width of the Naruto Bridge in Japan. Based on the same principle, this approach is also applicable to spaceborne ALOSPALSAR single-polarization data of the Eastern Ocean Bridge in China. The results show good feasibility to realize the bridge height inversion.

Underwater photography for bridge inspections.

DOT National Transportation Integrated Search

1983-01-01

A photographic technique was developed that enables divers in the Department to obtain clear photographs under typical conditions encountered in inspecting bridge components underwater. The equipment selected for the technique is inexpensive, readily...

Deterioration and cost information for bridge management.

DOT National Transportation Integrated Search

2012-05-01

This study applies contract bid tabulations and elementlevel condition records to develop elementlevel actions, : costs for actions, transition probabilities for models of deterioration of bridge elements, and transition probabilities : for imp...

Vibration characteristics and damage detection in a suspension bridge

NASA Astrophysics Data System (ADS)

Wickramasinghe, Wasanthi R.; Thambiratnam, David P.; Chan, Tommy H. T.; Nguyen, Theanh

2016-08-01

Suspension bridges are flexible and vibration sensitive structures that exhibit complex and multi-modal vibration. Due to this, the usual vibration based methods could face a challenge when used for damage detection in these structures. This paper develops and applies a mode shape component specific damage index (DI) to detect and locate damage in a suspension bridge with pre-tensioned cables. This is important as suspension bridges are large structures and damage in them during their long service lives could easily go un-noticed. The capability of the proposed vibration based DI is demonstrated through its application to detect and locate single and multiple damages with varied locations and severity in the cables of the suspension bridge. The outcome of this research will enhance the safety and performance of these bridges which play an important role in the transport network.

An overheight vehicle bridge collision monitoring system using piezoelectric transducers

NASA Astrophysics Data System (ADS)

Song, G.; Olmi, C.; Gu, H.

2007-04-01

With increasing traffic volume follows an increase in the number of overheight truck collisions with highway bridges. The detection of collision impact and evaluation of the impact level is a critical issue in the maintenance of a concrete bridge. In this paper, an overheight collision detection and evaluation system is developed for concrete bridge girders using piezoelectric transducers. An electric circuit is designed to detect the impact and to activate a digital camera to take photos of the offending truck. Impact tests and a health monitoring test were conducted on a model concrete bridge girder by using three piezoelectric transducers embedded before casting. From the experimental data of the impact test, it can be seen that there is a linear relation between the output of sensor energy and the impact energy. The health monitoring results show that the proposed damage index indicates the level of damage inside the model concrete bridge girder. The proposed overheight truck-bridge collision detection and evaluation system has the potential to be applied to the safety monitoring of highway bridges.

Analysis of longitudinal seismic response of bridge with magneto-rheological elastomeric bearings

NASA Astrophysics Data System (ADS)

Li, Rui; Li, Xi; Wu, Yueyuan; Chen, Shiwei; Wang, Xiaojie

2016-04-01

As the weakest part in the bridge system, traditional bridge bearing is incapable of isolating the impact load such as earthquake. A magneto-rheological elastomeric bearing (MRB) with adjustable stiffness and damping parameters is designed, tested and modeled. The developed Bouc-Wen model is adopted to represent the constitutive relation and force-displacement behavior of an MRB. Then, the lead rubber bearing (LRB), passive MRB and controllable MRB are modeled by finite element method (FEM). Furthermore, two typical seismic waves are adopted as inputs for the isolation system of bridge seismic response. The experiments are carried out to investigate the different response along the bridge with on-off controlled MRBs. The results show that the isolating performance of MRB is similar to that of traditional LRB, which ensures the fail-safe capability of bridge with MRBs under seismic excitation. In addition, the controllable bridge with MRBs demonstrated the advantage of isolating capacity and energy dissipation, because it restrains the acceleration peak of bridge beam by 33.3%, and the displacement of bearing decrease by 34.1%. The shear force of the pier top is also alleviated.

Morphological aspects of myocardial bridges.

PubMed

Lujinović, Almira; Kulenović, Amela; Kapur, Eldan; Gojak, Refet

2013-11-01

Although some myocardial bridges can be asymptomatic, their presence often causes coronary disease either through direct compression of the "tunnel" segment or through stimulation and accelerated development of atherosclerosis in the segment proximally to the myocardial bridge. The studied material contained 30 human hearts received from the Department of Anatomy. The hearts were preserved 3 to 5 days in 10% formalin solution. Thereafter, the fatty tissue was removed and arterial blood vessels prepared by careful dissection with special reference to the presence of the myocardial bridges. Length and thickness of the bridges were measured by the precise electronic caliper. The angle between the myocardial bridge fibre axis and other axis of the crossed blood vessel was measured by a goniometer. The presence of the bridges was confirmed in 53.33% of the researched material, most frequently (43.33%) above the anterior interventricular branch. The mean length of the bridges was 14.64 ± 9.03 mm and the mean thickness was 1.23 ± 1.32 mm. Myocardial bridge fibres pass over the descending blood vessel at the angle of 10-90 degrees. The results obtained on a limited sample suggest that the muscular index of myocardial bridge is the highest for bridges located on RIA, but that the difference is not significant in relation to bridges located on other branches. The results obtained suggest that bridges located on other branches, not only those on RIA, could have a great contractive power and, consequently, a great compressive force, which would be exerted on the wall of a crossed blood vessel.

Bridging the Divide: Developing a Scholarly Habitus for Aspiring Graduate Students through Summer Bridge Programs Participation

ERIC Educational Resources Information Center

McCoy, Dorian L.; Winkle-Wagner, Rachelle

2015-01-01

This multisite case study explored the role of summer institutes in preparing Students of Color for doctoral programs. Bourdieu's social reproduction theory, particularly the concept of habitus, was employed as a theoretical framework to investigate how the participants further developed habitus (their dispositions, identities, and perspectives)…

Development of a smart timber bridge girder with fiber optic sensors

Treesearch

James Wacker; Ursula Deza; Brent M. Phares; Terry J. Wipf

2010-01-01

Past timber bridge evaluation and maintenance efforts in the USA have principally focused on the internal integrity of timber components using various non-destructive evaluation tools to supplement visual inspection data. This project is part of a comprehensive effort to develop smart structure concepts for improving the long-term performance, maintenance, and...

Development of a cost-effective concrete bridge deck preservation program : volume 1--development and implementation of the experimental program.

DOT National Transportation Integrated Search

2016-07-01

The deterioration of bridge decks has been identified as a major problem in Indiana. The primary cause of this deterioration is salt water : ingress from the application of deicing salts during the winter. Deicing chemicals placed on the road mix wit...

A Collaborative Approach to Bridging the Research-Policy Gap through the Development of Policy Advice Software

ERIC Educational Resources Information Center

Milne, Barry John; Lay-Yee, Roy; McLay, Jessica; Tobias, Martin; Tuohy, Pat; Armstrong, Ann; Lynn, Robert; Pearson, Janet; Mannion, Oliver; Davis, Peter

2014-01-01

We have developed a software-based tool to support a dynamic micro-simulation model of life-course development (to age 13) as an aid to policy makers assessing the impact of policies affecting children. We demonstrate how this approach bridges the research-policy gap by creating: (1) an easy transfer of evidence in a form that policymakers can use…

A survey and photographic inventory of metal truss bridges in Virginia, 1865-1932 : I : an examination of the development of the truss form including an annotated list of nineteenth and twentieth century bridge companies.

DOT National Transportation Integrated Search

1975-01-01

The romance and myths long associated with the covered wooden bridges that once populated the rural roads of the American landscape have produced a multitude of popular literary works on their form, purpose and ultimately demise. Consequently, covere...

Development of a 2 MHz Sonar Sensor for Inspection of Bridge Substructures.

PubMed

Park, Chul; Kim, Youngseok; Lee, Heungsu; Choi, Sangsik; Jung, Haewook

2018-04-16

Hydraulic factors account for a large part of the causes of bridge collapse. Due to the nature of the underwater environment, quick and accurate inspection is required when damage occurs. In this study, we developed a 2 MHz side scan sonar sensor module and effective operation technique by improving the limitations of existing sonar. Through field tests, we analyzed the correlation of factors affecting the resolution of the sonar data such as the angle of survey, the distance from the underwater structure and the water depth. The effect of the distance and the water depth and the structure on the survey angle was 66~82%. We also derived the relationship between these factors as a regression model for effective operating techniques. It is considered that application of the developed 2 MHz side scan sonar and its operation method could contribute to prevention of bridge collapses and disasters by quickly and accurately checking the damage of bridge substructures due to hydraulic factors.

Development of a 2 MHz Sonar Sensor for Inspection of Bridge Substructures

PubMed Central

Park, Chul; Lee, Heungsu; Choi, Sangsik; Jung, Haewook

2018-01-01

Hydraulic factors account for a large part of the causes of bridge collapse. Due to the nature of the underwater environment, quick and accurate inspection is required when damage occurs. In this study, we developed a 2 MHz side scan sonar sensor module and effective operation technique by improving the limitations of existing sonar. Through field tests, we analyzed the correlation of factors affecting the resolution of the sonar data such as the angle of survey, the distance from the underwater structure and the water depth. The effect of the distance and the water depth and the structure on the survey angle was 66~82%. We also derived the relationship between these factors as a regression model for effective operating techniques. It is considered that application of the developed 2 MHz side scan sonar and its operation method could contribute to prevention of bridge collapses and disasters by quickly and accurately checking the damage of bridge substructures due to hydraulic factors. PMID:29659557

Thick-to-Thin Filament Surface Distance Modulates Cross-Bridge Kinetics in Drosophila Flight Muscle

PubMed Central

Tanner, Bertrand C.W.; Farman, Gerrie P.; Irving, Thomas C.; Maughan, David W.; Palmer, Bradley M.; Miller, Mark S.

2012-01-01

The demembranated (skinned) muscle fiber preparation is widely used to investigate muscle contraction because the intracellular ionic conditions can be precisely controlled. However, plasma membrane removal results in a loss of osmotic regulation, causing abnormal hydration of the myofilament lattice and its proteins. We investigated the structural and functional consequences of varied myofilament lattice spacing and protein hydration on cross-bridge rates of force development and detachment in Drosophila melanogaster indirect flight muscle, using x-ray diffraction to compare the lattice spacing of dissected, osmotically compressed skinned fibers to native muscle fibers in living flies. Osmolytes of different sizes and exclusion properties (Dextran T-500 and T-10) were used to differentially alter lattice spacing and protein hydration. At in vivo lattice spacing, cross-bridge attachment time (ton) increased with higher osmotic pressures, consistent with a reduced cross-bridge detachment rate as myofilament protein hydration decreased. In contrast, in the swollen lattice, ton decreased with higher osmotic pressures. These divergent responses were reconciled using a structural model that predicts ton varies inversely with thick-to-thin filament surface distance, suggesting that cross-bridge rates of force development and detachment are modulated more by myofilament lattice geometry than protein hydration. Generalizing these findings, our results suggest that cross-bridge cycling rates slow as thick-to-thin filament surface distance decreases with sarcomere lengthening, and likewise, cross-bridge cycling rates increase during sarcomere shortening. Together, these structural changes may provide a mechanism for altering cross-bridge performance throughout a contraction-relaxation cycle. PMID:22995500

Thick-to-Thin Filament Surface Distance Modulates Cross-Bridge Kinetics in Drosophila Flight Muscle

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tanner, Bertrand C.W.; Farman, Gerrie P.; Irving, Thomas C.

2012-09-19

The demembranated (skinned) muscle fiber preparation is widely used to investigate muscle contraction because the intracellular ionic conditions can be precisely controlled. However, plasma membrane removal results in a loss of osmotic regulation, causing abnormal hydration of the myofilament lattice and its proteins. We investigated the structural and functional consequences of varied myofilament lattice spacing and protein hydration on cross-bridge rates of force development and detachment in Drosophila melanogaster indirect flight muscle, using x-ray diffraction to compare the lattice spacing of dissected, osmotically compressed skinned fibers to native muscle fibers in living flies. Osmolytes of different sizes and exclusion propertiesmore » (Dextran T-500 and T-10) were used to differentially alter lattice spacing and protein hydration. At in vivo lattice spacing, cross-bridge attachment time (t{sub on}) increased with higher osmotic pressures, consistent with a reduced cross-bridge detachment rate as myofilament protein hydration decreased. In contrast, in the swollen lattice, t{sub on} decreased with higher osmotic pressures. These divergent responses were reconciled using a structural model that predicts t{sub on} varies inversely with thick-to-thin filament surface distance, suggesting that cross-bridge rates of force development and detachment are modulated more by myofilament lattice geometry than protein hydration. Generalizing these findings, our results suggest that cross-bridge cycling rates slow as thick-to-thin filament surface distance decreases with sarcomere lengthening, and likewise, cross-bridge cycling rates increase during sarcomere shortening. Together, these structural changes may provide a mechanism for altering cross-bridge performance throughout a contraction-relaxation cycle.« less

Wind tunnel test of musi VI bridge

NASA Astrophysics Data System (ADS)

Permata, Robby; Andika, Matza Gusto; Syariefatunnisa, Risdhiawan, Eri; Hermawan, Budi; Noordiana, Indra

2017-11-01

Musi VI Bridge is planned to cross the Musi River in Palembang City, South Sumatera Province, Indonesia. The main span is a steel arch type with 200 m length and side span length is 75 m. Finite element analysis results showed that the bridge has frequency ratio for torsional and heaving mode (torsional frequency/heaving frequency)=1.14. This close to unity value rises concern about aerodynamic behaviour and stability of the bridge deck under wind loading. Sectional static and free vibration wind tunnel test were performed to clarify this phenomena in B2TA3 facility in Serpong, Indonesia. The test followed the draft of Guide of Wind Tunnel Test for Bridges developed by Indonesian Ministry of Public Works. Results from wind tunnel testing show that the bridge is safe from flutter instability and no coupled motion vibration observed. Therefore, low value of frequency ratio has no effect to aerodynamic behaviour of the bridge deck. Vortex-induced vibration in heaving mode occurred in relatively low wind velocity with permissible maximum amplitude value.

Lateral dynamic interaction analysis of a train girder pier system

NASA Astrophysics Data System (ADS)

Xia, H.; Guo, W. W.; Wu, X.; Pi, Y. L.; Bradford, M. A.

2008-12-01

A dynamic model of a coupled train-girder-pier system is developed in this paper. Each vehicle in a train is modeled with 27 degrees-of-freedom for a 4-axle passenger coach or freight car, and 31 for a 6-axle locomotive. The bridge model is applicable to straight and curved bridges. The centrifugal forces of moving vehicles on curved bridges are considered in both the vehicle model and the bridge model. The dynamic interaction between the bridge and train is realized through an assumed wheel-hunting movement. A case study is performed for a test train traversing two straight and two curved multi-span bridges with high piers. The histories of the train traversing the bridges are simulated and the dynamic responses of the piers and the train vehicles are calculated. A field experiment is carried out to verify the results of the analysis, by which the lateral resonant train speed inducing the peak pier-top amplitudes and some other observations are validated.

CAMPARE and Cal-Bridge: Two Institutional Networks Increasing Diversity in Astronomy

NASA Astrophysics Data System (ADS)

Rudolph, Alexander L.; Smecker-Hane, Tammy A.

2017-01-01

We describe two programs, CAMPARE and Cal-Bridge, with the common mission of increasing participation of groups traditionally underrepresented in astronomy, through summer research opportunities, in the case of CAMPARE, scholarships in the case of Cal-Bridge, and significant mentoring in both programs, creating a national impact on their numbers successfully pursuing a PhD in the field.In 7 years, the CAMPARE program has sent 80 students, >80% from underrepresented groups, to conduct summer research at one of 14 major research institutions throughout the country. The graduation rate among CAMPARE scholars is 98%, and of the CAMPARE scholars who have graduated with a Bachelor’s degree, more than 60% have completed or are pursuing graduate education in astronomy or a related field, at institutions including UCLA, UC Riverside, UC Irvine, UC Santa Barbara, USC, Stanford, Univ. of Arizona, Univ. of Washington, and the Fisk-Vanderbilt Master’s-to-PhD program.Now entering its third year, the Cal-Bridge program is a CSU-UC Bridge program comprised of over 75 physics and astronomy faculty from 5 University of California (UC), 9 California State University (CSU), and 14 California Community College (CCC) campuses in Southern California. In the first three years, 22 Cal-Bridge Scholars have been selected, including 11 Hispanic, 3 African-American and 8 female students, 5 of whom are from URM groups. Nineteen (19) of the 22 Cal-Bridge Scholars are first-generation college students. The entire first cohort of 4 Cal-Bridge scholars was accepted to one or more PhD programs in astronomy or physics, including UC Irvine, UC Santa Cruz, UC Davis, Michigan State, and Georgia State Universities. The second cohort of 8 Cal-Bridge scholars is applying to graduate schools this fall.Cal-Bridge provides much deeper mentoring and professional development experiences over the last two years of undergraduate and first year of graduate school to students from this diverse network of higher education institutions. Cal-Bridge Scholars benefit from substantial financial support, intensive, joint mentoring by CSU and UC faculty, professional development workshops, and exposure to research opportunities at the participating UC campuses.

Improved Simplified Methods for Effective Seismic Analysis and Design of Isolated and Damped Bridges in Western and Eastern North America

NASA Astrophysics Data System (ADS)

Koval, Viacheslav

The seismic design provisions of the CSA-S6 Canadian Highway Bridge Design Code and the AASHTO LRFD Seismic Bridge Design Specifications have been developed primarily based on historical earthquake events that have occurred along the west coast of North America. For the design of seismic isolation systems, these codes include simplified analysis and design methods. The appropriateness and range of application of these methods are investigated through extensive parametric nonlinear time history analyses in this thesis. It was found that there is a need to adjust existing design guidelines to better capture the expected nonlinear response of isolated bridges. For isolated bridges located in eastern North America, new damping coefficients are proposed. The applicability limits of the code-based simplified methods have been redefined to ensure that the modified method will lead to conservative results and that a wider range of seismically isolated bridges can be covered by this method. The possibility of further improving current simplified code methods was also examined. By transforming the quantity of allocated energy into a displacement contribution, an idealized analytical solution is proposed as a new simplified design method. This method realistically reflects the effects of ground-motion and system design parameters, including the effects of a drifted oscillation center. The proposed method is therefore more appropriate than current existing simplified methods and can be applicable to isolation systems exhibiting a wider range of properties. A multi-level-hazard performance matrix has been adopted by different seismic provisions worldwide and will be incorporated into the new edition of the Canadian CSA-S6-14 Bridge Design code. However, the combined effect and optimal use of isolation and supplemental damping devices in bridges have not been fully exploited yet to achieve enhanced performance under different levels of seismic hazard. A novel Dual-Level Seismic Protection (DLSP) concept is proposed and developed in this thesis which permits to achieve optimum seismic performance with combined isolation and supplemental damping devices in bridges. This concept is shown to represent an attractive design approach for both the upgrade of existing seismically deficient bridges and the design of new isolated bridges.

Information-theoretical noninvasive damage detection in bridge structures

NASA Astrophysics Data System (ADS)

Sudu Ambegedara, Amila; Sun, Jie; Janoyan, Kerop; Bollt, Erik

2016-11-01

Damage detection of mechanical structures such as bridges is an important research problem in civil engineering. Using spatially distributed sensor time series data collected from a recent experiment on a local bridge in Upper State New York, we study noninvasive damage detection using information-theoretical methods. Several findings are in order. First, the time series data, which represent accelerations measured at the sensors, more closely follow Laplace distribution than normal distribution, allowing us to develop parameter estimators for various information-theoretic measures such as entropy and mutual information. Second, as damage is introduced by the removal of bolts of the first diaphragm connection, the interaction between spatially nearby sensors as measured by mutual information becomes weaker, suggesting that the bridge is "loosened." Finally, using a proposed optimal mutual information interaction procedure to prune away indirect interactions, we found that the primary direction of interaction or influence aligns with the traffic direction on the bridge even after damaging the bridge.

Potential-Scour Assessments at 130 Bridges in Iowa

USGS Publications Warehouse

Fischer, Edward E.

1996-01-01

A total of 130 highway bridges in Iowa were assessed for potential scour using a potential-scour index developed by the U.S. Geological Survey for a bridge-scour study in western Tennessee. Greater values of the index, which is composed of 11 components, suggest a greater likelihood of scour-related problems occurring at a bridge. For the Iowa assessments, the minimum value was 3, the median value was 11.5, and the maximum value was 24.5. None of the 130 bridges required immediate attention with regard to installing scour countermeasures. Based on the results of the assessments, it was concluded that assessing potential scour only once at a site would be of limited benefit in the Iowa Department of Transportation's bridge inspection program. Additional information would help determine whether repeated potential-scour assessments would enhance more timely and cost-effective implementation of scourcountermeasures.

Development of a liquefaction hazard screening tool for caltrans bridge sites

USGS Publications Warehouse

Knudsen, K.-L.; Bott, J.D.J.; Woods, M.O.; McGuire, T.L.

2009-01-01

We have developed a liquefaction hazard screening tool for the California Department of Transportation (Caltrans) that is being used to evaluate the liquefaction hazard to approximately 13,000 bridge sites in California. Because of the large number of bridge sites to be evaluated, we developed a tool that makes use of parameters not typically considered in site-specific liquefaction investigations. We assessed geologic, topographic, seismic hazard, and subsurface conditions at about 100 sites of past liquefaction in California. Among the parameters we found common to many of these sites are: (a) low elevations, (b) proximity to a water body, and (c) presence of geologically youthful deposits or artificial fill materials. The nature of the study necessitated the use of readily available data, preferably datasets that are consistent across the state. The screening tool we provided to Caltrans makes use of the following parameters: (1) proximity to a water body, (2) whether the bridge crosses a water body, (3) the age of site geologic materials and the environment in which the materials were deposited, as discerned from available digital geologic maps, (4) probabilistic shaking estimates, (5) the site elevation, (6) information from available liquefaction hazard maps [covering the 9-county San Francisco Bay Area and Ventura County] and California Geological Survey (CGS) Zones of Required Investigation. For bridge sites at which subsurface boring data were available (from CGS' existing database), we calculated Displacement Potential Index values using a methodology developed by Allison Faris and Jiaer Wu. Caltrans' staff will use this hazard-screening tool, along with other tools focused on bridges and foundations, to prioritize site-specific investigations. ?? 2009 ASCE.

Bridging and bonding interactions in higher education: social capital and students’ academic and professional identity formation

PubMed Central

Jensen, Dorthe H.; Jetten, Jolanda

2015-01-01

It is increasingly recognized that graduates’ achievements depend in important ways on their opportunities to develop an academic and a professional identity during their studies. Previous research has shown that students’ socio-economic status (SES) and social capital prior to entering university affects their ability to obtain these identities in higher education. However, what is less well understood is whether social capital that is built during university studies shapes identity development, and if so, whether the social capital gained during university years impacts on academic and professional identity differently. In a qualitative study, we interviewed 26 Danish and 11 Australian university students about their social interaction experiences, their opportunities to develop bonding capital as well as bridging capital, and their academic and professional identity. Findings show that while bonding social capital with co-students facilitated academic identity formation, such social capital does not lead to professional identity development. We also found that the development of bridging social capital with educators facilitated students’ professional identity formation. However, bonding social capital among students stood in the way of participating in bridging interaction with educators, thereby further hindering professional identity formation. Finally, while students’ parental background did not affect the perceived difficulty of forming professional identity, there was a tendency for students from lower SES backgrounds to be more likely to make internal attributions while those from higher SES backgrounds were more likely to make external attributions for the failure to develop professional identity. Results point to the importance of creating opportunities for social interaction with educators at university because this facilitates the generation of bridging social capital, which, in turn, is essential for students’ professional identity development. PMID:25762954

Bridging and bonding interactions in higher education: social capital and students' academic and professional identity formation.

PubMed

Jensen, Dorthe H; Jetten, Jolanda

2015-01-01

It is increasingly recognized that graduates' achievements depend in important ways on their opportunities to develop an academic and a professional identity during their studies. Previous research has shown that students' socio-economic status (SES) and social capital prior to entering university affects their ability to obtain these identities in higher education. However, what is less well understood is whether social capital that is built during university studies shapes identity development, and if so, whether the social capital gained during university years impacts on academic and professional identity differently. In a qualitative study, we interviewed 26 Danish and 11 Australian university students about their social interaction experiences, their opportunities to develop bonding capital as well as bridging capital, and their academic and professional identity. Findings show that while bonding social capital with co-students facilitated academic identity formation, such social capital does not lead to professional identity development. We also found that the development of bridging social capital with educators facilitated students' professional identity formation. However, bonding social capital among students stood in the way of participating in bridging interaction with educators, thereby further hindering professional identity formation. Finally, while students' parental background did not affect the perceived difficulty of forming professional identity, there was a tendency for students from lower SES backgrounds to be more likely to make internal attributions while those from higher SES backgrounds were more likely to make external attributions for the failure to develop professional identity. Results point to the importance of creating opportunities for social interaction with educators at university because this facilitates the generation of bridging social capital, which, in turn, is essential for students' professional identity development.

Seismic performance of quasi-isolated highway bridges in Illinois.

DOT National Transportation Integrated Search

2013-06-01

The Illinois Department of Transportation (IDOT) commonly uses elastomeric bearings to accommodate : thermal deformations in bridges, and these bearings have potential utility in seismic events. IDOT has developed : an Earthquake Resisting System (ER...

Highway Bridge Research Center final report : phase I.

DOT National Transportation Integrated Search

2005-01-01

The objective of this research was to demonstrate the effectiveness and feasibility of nondestructive testing and monitoring techniques for highway bridges. The work included: fiber optic sensor development where photonics instruments, fiber optic sp...

Evaluation of DOTD semi-integral bridge and abutment system.

DOT National Transportation Integrated Search

2005-03-01

The Louisiana Department of Transportation and Development (LADOTD) designed and constructed its first prototype semi-integral abutment bridge in 1989. In this design, large longitudinal movements due to expansion and contraction, creep, shrinkage, a...

Smart FRP Composite Sandwich Bridge Decks in Cold Regions

DOT National Transportation Integrated Search

2011-07-01

In this study, new and integrated Smart honeycomb Fiber-Reinforced Polymer (S-FRP) : sandwich materials for various transportation construction applications, with particular emphasis : on highway bridge decks in cold regions, were developed and teste...

Caltrans bridge inspection aerial robot.

DOT National Transportation Integrated Search

2008-10-01

The California Department of Transportation (Caltrans) project resulted in the development of a twin-motor, : single duct, electric-powered Aerobot designed of carrying video cameras up to 200 feet in elevation to enable : close inspection of bridges...

Portable Instrumentation for Real-Time Measurement of Scour at Bridges

DOT National Transportation Integrated Search

2000-12-01

Portable scour-measuring systems were developed to meet the requirements of three different applications: bridge inspections, limited-detail data collection, and detailed data collection. A portable scour-measuring system consists of four components:...

The rideability of a deflected bridge approach slab : technical summary report 457.

DOT National Transportation Integrated Search

2009-11-01

The Louisiana Department of Transportation and Development (LADOTD) initiated the Louisiana Quality : Initiative (LQI) entitled Preservation of Bridge Approach Rideability to explore different potential : methods of solving what has been observ...

Determination of barge impact probabilities for bridge design : [summary].

DOT National Transportation Integrated Search

2016-04-01

University of Florida researchers developed a revised barge impact probability expression applicable for the design of bridge structures located on Florida waterways. University of Florida researchers obtained barge flotilla traffic data and barge-to...

Developing Student Assessment Related to a Workplacement: A Bridge between Practice and Improvement

ERIC Educational Resources Information Center

Vuoskoski, Pirjo; Poikela, Sari

2015-01-01

This paper explores the ways in which student assessment can be developed in higher education and work-related contexts to form a strong bridge between practice and improvement. Our aim is to provide a starting point for evaluation and improvement of assessment practices, which benefits the learners, instructors, and designers of the curricula, as…

Plans for crash-tested bridge railings for longitudinal wood decks on low-volume roads

Treesearch

Michael A. Ritter; Ronald K. Faller; Steve Bunnell; Paula D. Hilbrich Lee; Barry T. Rosson

1998-01-01

The plans for crashworthy bridge railings for low-volume roads were developed through a cooperative research program involving the USDA Forest Service, Forest Products Laboratory (FPL); the Midwest Roadside Safety Facility, University of Nebraska-Lincoln (MwRSF); and the Forest Service, National Forest System, Engineering. Three railings were developed and successfully...

BioBridge Professional Development: Bringing Innovative Science into the Classroom

ERIC Educational Resources Information Center

Babendure, Jeremy; Thompson, Loren; Peterman, Karen; Teiper, Leanne; Gastil, Heather; Liwanag, Heather; Glenn-Lee, Shelley

2011-01-01

The BioBridge Professional Development model was created to bring current and relevant science into the high school classroom. The purpose of this intervention was to connect teachers with relevant science and to create innovative, hands-on activities that engage students, with the goal of increasing student interest in STEM careers. To this end,…

Suicides by jumping from iconic bridges in Hong Kong.

PubMed

Wong, P W C; Chan, W S C; Lau, T K; Morgan, P R; Yip, P S F

2009-01-01

Three bridges in Hong Kong have become iconic sites for suicide since their openings 11 years ago. This retrospective record-based study aimed to examine suicides by jumping from a group of three iconic bridges in Hong Kong, and to explore potential preventive strategies on these bridges to prevent future suicide. We examined the Coroner's files of 12 people who killed themselves by jumping from the bridges between 1997 and 2007. We also examined the Coroner's files of other suicides in 2003, and compared them with the bridge suicides. The majority of the suicides were male, middle-age (40-59 years), married or cohabiting, not living alone, employed or self-employed, and in financial difficulty. None of these cases had a reported psychiatric diagnosis or psychiatric care history, and only one case had a history of suicidal attempt. Compared with other suicides in Hong Kong, the bridge jumpers were more likely to be younger, holding a job, indebted, free from a psychiatric and attempt history, and to leave a suicide note (p < .05). The bridge suicide cases in Hong Kong also appeared to be different from the profiles of bridge jumpers in other countries. Erection of an effective safety barrier has been found to prevent bridge suicides in many countries. Given the different characteristics of bridge jumpers in Hong Kong and the technical difficulties, more innovative ways may be needed to prevent suicides by such means. Potential prevention measures are discussed and, hopefully, will better inform the future design and development of bridges of significance.

Status in the development of self-powered wireless sensor node for structural health monitoring and prognosis

NASA Astrophysics Data System (ADS)

Godinez-Azcuaga, Valery F.; Farmer, Justin; Ziehl, Paul H.; Giurgiutiu, Victor; Nanni, Antonio; Inman, Daniel J.

2012-04-01

This paper discusses the development status of a self-powered wireless sensor node for steel and concrete bridges monitoring and prognosis. By the end of the third year in this four-year cross-disciplinary project, the 4-channel acoustic emission wireless node, developed by Mistras Group Inc, has already been deployed in concrete structures by the University of Miami. Also, extensive testing is underway with the node powered by structural vibration and wind energy harvesting modules developed by Virginia Tech. The development of diagnosis tools and models for bridge prognosis, which will be discussed in the paper, continues and the diagnosis tools are expected to be programmed in the node's AVR during the 4th year of the project. The impact of this development extends beyond the area of bridge health monitoring into several fields, such as offshore oil platforms, composite components on military ships and race boats, combat deployable bridges and wind turbine blades. Some of these applications will also be discussed. This project was awarded to a joint venture formed by Mistras Group Inc, Virginia Tech, University of South Carolina and University of Miami by the National Institute of Standards and Technology through its Technology Innovation Program Grant #70NANB9H007.

Dynamic analysis of a long span, cable-stayed freeway bridge using NASTRAN

NASA Technical Reports Server (NTRS)

Salus, W. L.; Jones, R. E.; Ice, M. W.

1973-01-01

The dynamic analysis for earthquake- and wind-induced response of a long span, cable-stayed freeway bridge by NASTRAN in conjunction with post-processors is described. Details of the structural modeling, the input data generation, and numerical results are given. The influence of the dynamic analysis on the bridge design is traced from the project initiation to the development of a successful earthquake and wind resistant configuration.

Applications of infrared thermography for nondestructive testing of fatigue cracks in steel bridges

NASA Astrophysics Data System (ADS)

Sakagami, Takahide; Izumi, Yui; Kobayashi, Yoshihiro; Mizokami, Yoshiaki; Kawabata, Sunao

2014-05-01

In recent years, fatigue crack propagations in aged steel bridge which may lead to catastrophic structural failures have become a serious problem. For large-scale steel structures such as orthotropic steel decks in highway bridges, nondestructive inspection of deteriorations and fatigue damages are indispensable for securing their safety and for estimating their remaining strength. As conventional NDT techniques for steel bridges, visual testing, magnetic particle testing and ultrasonic testing have been commonly employed. However, these techniques are time- and labor- consuming techniques, because special equipment is required for inspection, such as scaffolding or a truck mount aerial work platform. In this paper, a new thermography NDT technique, which is based on temperature gap appeared on the surface of structural members due to thermal insulation effect of the crack, is developed for detection of fatigue cracks. The practicability of the developed technique is demonstrated by the field experiments for highway steel bridges in service. Detectable crack size and factors such as measurement time, season or spatial resolution which influence crack detectability are investigated.

Development of a numerical model for vehicle-bridge interaction analysis of railway bridges

NASA Astrophysics Data System (ADS)

Kim, Hee Ju; Cho, Eun Sang; Ham, Jun Su; Park, Ki Tae; Kim, Tae Heon

2016-04-01

In the field of civil engineering, analyzing dynamic response was main concern for a long time. These analysis methods can be divided into moving load analysis method and moving mass analysis method, and formulating each an equation of motion has recently been studied after dividing vehicles and bridges. In this study, the numerical method is presented, which can consider the various train types and can solve the equations of motion for a vehicle-bridge interaction analysis by non-iteration procedure through formulating the coupled equations for motion. Also, 3 dimensional accurate numerical models was developed by KTX-vehicle in order to analyze dynamic response characteristics. The equations of motion for the conventional trains are derived, and the numerical models of the conventional trains are idealized by a set of linear springs and dashpots with 18 degrees of freedom. The bridge models are simplified by the 3 dimensional space frame element which is based on the Euler-Bernoulli theory. The rail irregularities of vertical and lateral directions are generated by PSD functions of the Federal Railroad Administration (FRA).

Vulnerability of bridges to scour: insights from an international expert elicitation workshop

NASA Astrophysics Data System (ADS)

Lamb, Rob; Aspinall, Willy; Odbert, Henry; Wagener, Thorsten

2017-08-01

Scour (localised erosion) during flood events is one of the most significant threats to bridges over rivers and estuaries, and has been the cause of numerous bridge failures, with damaging consequences. Mitigation of the risk of bridges being damaged by scour is therefore important to many infrastructure owners, and is supported by industry guidance. Even after mitigation, some residual risk remains, though its extent is difficult to quantify because of the uncertainties inherent in the prediction of scour and the assessment of the scour risk. This paper summarises findings from an international expert workshop on bridge scour risk assessment that explores uncertainties about the vulnerability of bridges to scour. Two specialised structured elicitation methods were applied to explore the factors that experts in the field consider important when assessing scour risk and to derive pooled expert judgements of bridge failure probabilities that are conditional on a range of assumed scenarios describing flood event severity, bridge and watercourse types and risk mitigation protocols. The experts' judgements broadly align with industry good practice, but indicate significant uncertainty about quantitative estimates of bridge failure probabilities, reflecting the difficulty in assessing the residual risk of failure. The data and findings presented here could provide a useful context for the development of generic scour fragility models and their associated uncertainties.

CAMPARE and Cal-Bridge: Two Institutional Networks Increasing Diversity in Astronomy

NASA Astrophysics Data System (ADS)

Rudolph, Alexander L.; Impey, Chris David; Smecker-Hane, Tammy A.

2016-01-01

We describe two programs, CAMPARE and Cal-Bridge, with the common mission of increasing participation of groups traditionally underrepresented in astronomy, through summer research opportunities, in the case of CAMPARE, scholarships in the case of Cal-Bridge, and significant mentoring in both programs, leading to an increase in their numbers successfully pursuing a PhD in the field.In 6 years, the CAMPARE program has sent 62 students, >85% from underrepresented groups, to conduct summer research at one of twelve major research institutions in California, Arizona, and Wyoming. The graduation rate among CAMPARE scholars is 97%, and of the 37 CAMPARE scholars who have graduated with a Bachelor's degree, almost 60% (21) have completed or are pursuing graduate education in astronomy or a related field, at institutions including UCLA, USC, UC Riverside, Stanford, Univ. of Rochester, Georgia Tech, Kent State, Indiana Univ., Univ. of Oregon, Syracuse, and the Fisk-Vanderbilt Master's-to-PhD program. The Cal-Bridge program is a CSU-UC Bridge program comprised of faculty form 5 University of California (UC), 8 California State University (CSU), and 8 California Community College (CCC) campuses in Southern California. Cal-Bridge provides much deeper mentoring and professional development experiences over the last two years of undergraduate and first year of graduate school to students from this diverse network of higher education institutions. Cal-Bridge Scholars benefit from financial support, intensive, joint mentoring by CSU and UC faculty, professional development workshops, and exposure to research opportunities at the participating UC campuses.

Development of an intelligent hydroinformatic system for real-time monitoring and assessment of civil infrastructure

NASA Astrophysics Data System (ADS)

Cahill, Paul; Michalis, Panagiotis; Solman, Hrvoje; Kerin, Igor; Bekic, Damir; Pakrashi, Vikram; McKeogh, Eamon

2017-04-01

With the effects of climate change becoming more apparent, extreme weather events are now occurring with greater frequency throughout the world. Such extreme events have resulted in increased high intensity flood events which are having devastating consequences on hydro-structures, especially on bridge infrastructure. The remote and often inaccessible nature of such bridges makes inspections problematic, a major concern if safety assessments are required during and after extreme flood events. A solution to this is the introduction of smart, low cost sensing solutions at locations susceptible to hydro-hazards. Such solutions can provide real-time information on the health of the bridge and its environments, with such information aiding in the mitigation of the risks associated with extreme weather events. This study presents the development of an intelligent system for remote, real-time monitoring of hydro-hazards to bridge infrastructure. The solution consists of two types of remote monitoring stations which have the capacity to monitor environmental conditions and provide real-time information to a centralized, big data database solution, from which an intelligent decision support system will accommodate the results to control and manage bridge, river and catchment assets. The first device developed as part of the system is the Weather Information Logging Device (WILD), which monitors rainfall, temperature and air and soil moisture content. The ability of the WILD to monitor rainfall in real time enables flood early warning alerts and predictive river flow conditions, thereby enabling decision makers the ability to make timely and effective decisions about critical infrastructures in advance of extreme flood events. The WILD is complemented by a second monitoring device, the Bridge Information Recording Device (BIRD), which monitors water levels at a given location in real-time. The monitoring of water levels of a river allows for, among other applications, hydraulic modelling to assess the likely impact that severe flood events will have on a bridges foundation, particularly due to scour. The process of reading and validating data from the WILD and BIRD buffer servers is outlined, as is the transmission protocol used for the sending of recorded data to a centralized repository for further use and analysis. Finally, the development of a centralized repository for the collection of data from the WILD and BIRD devices is presented. Eventually the big data solution would be used to receive, store and send the monitored data to the hydrological models, whether existing or developed, and the results would be transmitted to the intelligent decision support system based on a web-based platform, for managing, planning and executing data, processes and procedures for bridge assets. The development of intelligent hydroinformatic system is an important tool for the protection of key infrastructure assets from the increasingly common effects of climate change. Acknowledgement The authors wish to acknowledge the financial support of the European Commission, through the Marie Curie Industry-Academia Partnership and Pathways Network BRIDGE SMS (Intelligent Bridge Assessment Maintenance and Management System) - FP7-People-2013-IAPP- 612517.

Flexural anchorage performance at diagonal crack locations.

DOT National Transportation Integrated Search

2010-12-01

Large numbers of reinforced concrete deck girder bridges that were constructed during the interstate system expansion of the 1950s have developed diagonal cracking in the stems. Though compliant with design codes when constructed, many of these bridg...

Seismic retrofit guidelines for Utah highway bridges.

DOT National Transportation Integrated Search

2009-05-01

Much of Utahs population dwells in a seismically active region, and many of the bridges connecting transportation lifelines predate the rigorous seismic design standards that have been developed in the past 10-20 years. Seismic retrofitting method...

Sediment control in bridge waterways.

DOT National Transportation Integrated Search

1990-02-01

The objective of this study was to develop guidelines for use of the Iowa Vanes : technique for sediment control in bridge waterways. Iowa Vanes are small flow-training : structures (foils) designed to modify the near-bed flow pattern and redistribut...

Continuous prestressed concrete girder bridges volume 1 : literature review and preliminary designs.

DOT National Transportation Integrated Search

2012-06-01

The Texas Department of Transportation (TxDOT) is currently designing typical highway bridge structures as simply supported using standard precast, pretensioned girders. TxDOT is interested in developing additional economical design alternatives for ...

Application of non-destructive testing to evaluate unknown foundations for Pennsylvania bridges.

DOT National Transportation Integrated Search

2013-08-01

Unknown bridge foundations present a unique challenge to Departments of Transportation (DOT) across the country since : foundation characteristics are a necessary input to assess scour vulnerability and to develop appropriate scour countermeasures. :...

Smart FRP Composite Sandwich Bridge Decks in Cold Regions

DOT National Transportation Integrated Search

2011-07-01

In this study, new and integrated Smart honeycomb Fiber-Reinforced Polymer (S-FRP) sandwich materials for various transportation construction applications, with particular emphasis on highway bridge decks in cold regions, were developed and tested. T...

Research notes : faster load rating for steel truss bridges.

DOT National Transportation Integrated Search

2009-03-01

The Oregon Department of Transportation (ODOT) Bridge Engineering Section recently completed a project with Oregon State University to develop a viable, more cost-effective alternative to the manually collected field measurement procedure. The new me...

Fatigue reliability of steel highway bridge details.

DOT National Transportation Integrated Search

2001-08-01

The expected life of a steel highway bridge subjected to random, variable-amplitude traffic cycles is highly dependent on damage accumulation caused by various fatigue mechanisms. This study addressed some of the issues associated with developing pro...

Phase I development of an aesthetic, precast concrete bridge rail.

DOT National Transportation Integrated Search

2012-02-01

Precast concrete bridge rail systems offer several advantages over traditional cast-in-place rail designs, including reduced construction : time and costs, installation in a wide range of environmental conditions, easier maintenance and repair, impro...

Enhanced ultrasonic inspection of steel bridge pin components.

DOT National Transportation Integrated Search

1998-01-01

This report describes the development of a technique for obtaining a reliable assessment of the condition of steel bridge pins already determined by ultrasound to contain imperfections. The details of a technique for performing high-definition ultras...

Geospatial wetlands impacts and mitigation forecasting models.

DOT National Transportation Integrated Search

2017-06-30

The South Carolina Department of Transportation (SCDOT) develops near (3-5 years) and long (15- 20 years) range plans for road widening, alignment, bridge replacement, and new road construction. Each road/bridge project may impact wetlands or streams...

Standardization of quality control plans for highway bridges in Europe: COST Action TU 1406

NASA Astrophysics Data System (ADS)

Casas, Joan R.; Matos, Jose Campos e.

2017-09-01

In Europe, as all over the world, the need to manage roadway bridges in an efficient way led to the development of different management systems. Hence, nowadays, many European countries have their own system. Although they present a similar architectural framework, several differences can be appointed. These differences constitute a divergent mechanism that may conduct to different decisions on maintenance actions. Within the roadway bridge management process, the identification of maintenance needs is more effective when developed in a uniform and repeatable manner. This process can be accomplished by the identification of performance indicators and definition of performance goals and key performance indicators (KPI), improving the planning of maintenance strategies. Therefore, a discussion at a European level, seeking to achieve a standardized approach in this subject, will bring significant benefits. Accordingly, a COST Action is under way in Europe with the aim of standardizing the establishment of quality control plans for roadway bridges.

Sensing sheet: the response of full-bridge strain sensors to thermal variations for detecting and characterizing cracks

NASA Astrophysics Data System (ADS)

Tung, S.-T.; Glisic, B.

2016-12-01

Sensing sheets based on large-area electronics consist of a dense array of unit strain sensors. This new technology has potential for becoming an effective and affordable monitoring tool that can identify, localize and quantify surface damage in structures. This research contributes to their development by investigating the response of full-bridge unit strain sensors to thermal variations. Overall, this investigation quantifies the effects of temperature on thin-film full-bridge strain sensors monitoring uncracked and cracked concrete. Additionally, an empirical formula is developed to estimate crack width given an observed strain change and a measured temperature change. This research led to the understanding of the behavior of full-bridge strain sensors installed on cracked concrete and exposed to temperature variations. It proves the concept of the sensing sheet and its suitability for application in environments with variable temperature.

Consistency assessment with global and bridging development strategies in emerging markets.

PubMed

Li, Gang; Chen, Josh; Quan, Hui; Shentu, Yue

2013-11-01

Global trial strategy with the participation of all major regions including countries from emerging markets surely increases new drug development efficiency. Nevertheless, there are circumstances in which some countries in emerging markets cannot join the original global trial. To evaluate the extrapolability of the original trial results to a new country, a bridging trial in the country has to be conducted. In this paper, we first evaluate the efficiency loss of the bridging trial strategy compared to that of the global trial strategy as a function of between-study variability from consistency assessment perspective. The provided evidence should encourage countries in emerging markets to make a greater effort to participate in the original global trial. We then discuss sample size requirement for desired assurance probability for consistency assessment based on various approaches for both global and bridging trial strategies. Examples are presented for numerical demonstration and comparisons. Copyright © 2013 Elsevier Inc. All rights reserved.

Chromothripsis and kataegis induced by telomere crisis

PubMed Central

Maciejowski, John; Li, Yilong; Bosco, Nazario; Campbell, Peter J.; de Lange, Titia

2015-01-01

Telomere crisis occurs during tumorigenesis when depletion of the telomere reserve leads to frequent telomere fusions. The resulting dicentric chromosomes have been proposed to drive genome instability. Here we examine the fate of dicentric human chromosomes in telomere crisis. We observed that dicentric chromosomes invariably persisted through mitosis and developed into 50-200 μm chromatin bridges connecting the daughter cells. Before their resolution at 3-20 h after anaphase, the chromatin bridges induced nuclear envelope rupture in interphase, accumulated the cytoplasmic 3' nuclease TREX1, and developed RPA-coated single stranded (ss) DNA. CRISPR knockouts showed that TREX1 contributed to the generation of the ssDNA and the resolution of the chromatin bridges. Post-crisis clones showed chromothripsis and kataegis, presumably resulting from DNA repair and APOBEC editing of the fragmented chromatin bridge DNA. We propose that chromothripsis in human cancer may arise through TREX1-mediated fragmentation of dicentric chromosomes formed in telomere crisis. PMID:26687355

An HF coaxial bridge for measuring impedance ratios up to 1 MHz

NASA Astrophysics Data System (ADS)

Kucera, J.; Sedlacek, R.; Bohacek, J.

2012-08-01

A four-terminal pair coaxial ac bridge developed for calibrating both resistance and capacitance ratios and working in the frequency range from 100 kHz up to 1 MHz is described. A reference inductive voltage divider (IVD) makes it possible to calibrate ratios 1:1 and 10:1 with uncertainty of a few parts in 105. The IVD is calibrated by means of a series-parallel capacitance device (SPCD). Use of the same ac bridge with minimal changes for calibrating the SPCD, IVD and unknown impedances simplifies the whole calibration process. The bridge balance conditions are fulfilled with simple capacitance and resistance decades and by injecting voltage supplied from the auxiliary direct digital synthesizer. Bridge performance was checked on the basis of resistance ratio measurements and also capacitance ratio measurements.

A Bridge Too Far or a Bridge to the Future? A Case Study in Online Assessment at Charles Sturt University

ERIC Educational Resources Information Center

Buchan, Janet F.; Swann, Michael

2007-01-01

The in house development of an online assessment tool, OASIS, has provided a unique opportunity to research the use of online assessment in teaching and learning across the university. The developing relationship between IT staff, educational designers and academics serves as a model for integrated and evolving management systems which demonstrate…

Building the Bridge between Science and Practice: Essential Characteristics of a Translational Framework

ERIC Educational Resources Information Center

Stafford-Brizard, K. Brooke; Cantor, Pamela; Rose, L. Todd

2017-01-01

Mind, brain, and education is a field developed with two key purposes: (1) to accelerate the knowledge developed through research by using an interdisciplinary approach, and (2) to create a bridge to connect and apply this knowledge to educational practice. While great progress has been made with regard to the interdisciplinary efforts of mind,…

Bilingual Resource Instruction for the Development of Gainful Employment Skills. Project BRIDGES 1988-89. OREA Evaluation Section Report.

ERIC Educational Resources Information Center

Berney, Tomi D.; Plotkin, Donna

Project BRIDGES, a 3-year program conducted for students of limited English proficiency (LEP) at three High Schools in Brooklyn (New York City) sought to develop the English language, academic, and vocational skills of a high-risk LEP population. The native languages of the participating students were Haitian Creole, Spanish, Chinese, Hebrew, and…

Feasibility of Building Bridges between School and Homes in Developing ESL Literacy: The SPIRE Project

ERIC Educational Resources Information Center

BavaHarji, Madhubala; Letchumanan, Krishnaveni; Bhar, Sareen Kaur

2014-01-01

This paper presents a feasible framework for building bridges between schools and homes to develop five year olds ESL literacy skills, using storybooks as a springboard. A reading program, i.e. Smart Partnership in Reading in English (SPIRE) was designed in response to the government's aspiration to raise literacy rates to 100% by 2020 and the…

Dexter energy transfer pathways

PubMed Central

Skourtis, Spiros S.; Liu, Chaoren; Antoniou, Panayiotis; Virshup, Aaron M.; Beratan, David N.

2016-01-01

Energy transfer with an associated spin change of the donor and acceptor, Dexter energy transfer, is critically important in solar energy harvesting assemblies, damage protection schemes of photobiology, and organometallic opto-electronic materials. Dexter transfer between chemically linked donors and acceptors is bridge mediated, presenting an enticing analogy with bridge-mediated electron and hole transfer. However, Dexter coupling pathways must convey both an electron and a hole from donor to acceptor, and this adds considerable richness to the mediation process. We dissect the bridge-mediated Dexter coupling mechanisms and formulate a theory for triplet energy transfer coupling pathways. Virtual donor–acceptor charge-transfer exciton intermediates dominate at shorter distances or higher tunneling energy gaps, whereas virtual intermediates with an electron and a hole both on the bridge (virtual bridge excitons) dominate for longer distances or lower energy gaps. The effects of virtual bridge excitons were neglected in earlier treatments. The two-particle pathway framework developed here shows how Dexter energy-transfer rates depend on donor, bridge, and acceptor energetics, as well as on orbital symmetry and quantum interference among pathways. PMID:27382185

Methodology and Estimates of Scour at Selected Bridge Sites in Alaska

USGS Publications Warehouse

Heinrichs, Thomas A.; Kennedy, Ben W.; Langley, Dustin E.; Burrows, Robert L.

2001-01-01

The U.S. Geological Survey estimated scour depths at 325 bridges in Alaska as part of a cooperative agreement with the Alaska Department of Transportation and Public Facilities. The department selected these sites from approximately 806 State-owned bridges as potentially susceptible to scour during extreme floods. Pier scour and contraction scour were computed for the selected bridges by using methods recommended by the Federal Highway Administration. The U.S. Geological Survey used a four-step procedure to estimate scour: (1) Compute magnitudes of the 100- and 500-year floods. (2) Determine cross-section geometry and hydraulic properties for each bridge site. (3) Compute the water-surface profile for the 100- and 500-year floods. (4) Compute contraction and pier scour. This procedure is unique because the cross sections were developed from existing data on file to make a quantitative estimate of scour. This screening method has the advantage of providing scour depths and bed elevations for comparison with bridge-foundation elevations without the time and expense of a field survey. Four examples of bridge-scour analyses are summarized in the appendix.

Learning Bridge: Curricular Integration of Didactic and Experiential Education

PubMed Central

Arendt, Cassandra S.; Cawley, Pauline; Buhler, Amber V.; Elbarbry, Fawzy; Roberts, Sigrid C.

2010-01-01

Objectives To assess the impact of a program to integrate introductory pharmacy practice experiences with pharmaceutical science topics by promoting active learning, self-directed learning skills, and critical-thinking skills. Design The Learning Bridge, a curriculum program, was created to better integrate the material first-year (P1) students learned in pharmaceutical science courses into their introductory pharmacy practice experiences. Four Learning Bridge assignments required students to interact with their preceptors and answer questions relating to the pharmaceutical science material concurrently covered in their didactic courses. Assessment Surveys of students and preceptors were conducted to measure the effectiveness of the Learning Bridge process. Feedback indicated the Learning Bridge promoted students' interaction with their preceptors as well as development of active learning, self-directed learning, and critical-thinking skills. Students also indicated that the Learning Bridge assignments increased their learning, knowledge of drug information, and comprehension of relevant data in package inserts. Conclusion The Learning Bridge process integrated the didactic and experiential components of the curriculum, enhancing student learning in both areas, and offered students educational opportunities to interact more with their preceptors. PMID:20498741

Dexter energy transfer pathways.

PubMed

Skourtis, Spiros S; Liu, Chaoren; Antoniou, Panayiotis; Virshup, Aaron M; Beratan, David N

2016-07-19

Energy transfer with an associated spin change of the donor and acceptor, Dexter energy transfer, is critically important in solar energy harvesting assemblies, damage protection schemes of photobiology, and organometallic opto-electronic materials. Dexter transfer between chemically linked donors and acceptors is bridge mediated, presenting an enticing analogy with bridge-mediated electron and hole transfer. However, Dexter coupling pathways must convey both an electron and a hole from donor to acceptor, and this adds considerable richness to the mediation process. We dissect the bridge-mediated Dexter coupling mechanisms and formulate a theory for triplet energy transfer coupling pathways. Virtual donor-acceptor charge-transfer exciton intermediates dominate at shorter distances or higher tunneling energy gaps, whereas virtual intermediates with an electron and a hole both on the bridge (virtual bridge excitons) dominate for longer distances or lower energy gaps. The effects of virtual bridge excitons were neglected in earlier treatments. The two-particle pathway framework developed here shows how Dexter energy-transfer rates depend on donor, bridge, and acceptor energetics, as well as on orbital symmetry and quantum interference among pathways.

Comparative evaluation of concrete bridge deck sealers.

DOT National Transportation Integrated Search

2015-08-01

The main objective of this research was to compare the performance of five bridge deck sealer products using a : synthesis of two testing methods: NCHRP Report 244 Series II tests and standards developed by the Alberta : Ministry of Transportation (B...

On-the-spot damage detection methodology for highway bridges.

DOT National Transportation Integrated Search

2010-07-01

Vibration-based damage identification (VBDI) techniques have been developed in part to address the problems associated with an aging civil infrastructure. To assess the potential of VBDI as it applies to highway bridges in Iowa, three applications of...

Analysis of Ethane and Diethylbenzene Bridged Sorbents

DTIC Science & Technology

2017-12-13

Leska; P.T. Charles; B.J. Melde; J.R. Taft, "Electrochemical Detection with Preconcentration: Nitroenergetic Contaminants ," Chemosensors 2, 131...monitoring of contaminants in groundwater: Sorbent development; Naval Research Laboratory: 2013. Analysis of Ethane and Diethylbenzene Bridged Sorbents 7...

The rideability of a deflected bridge approach slab.

DOT National Transportation Integrated Search

2009-11-01

This report presents the findings associated with the development of a new pavement roughness index called the Posted Speed Localized Roughness Index (LRIPS) that can be used to rate the ride quality on bridge approach slabs. Currently established pa...

CAESAR : an expert system for evaluation of scour and stream stability

DOT National Transportation Integrated Search

1999-01-01

This report documents the development and testing of a field-deployable, knowledge-based decision support system that assists bridge inspectors by acquiring, cataloging, storing, and retrieving information necessary for the evaluation of a bridge for...

Flexural anchorage performance at diagonal crack locations : final report.

DOT National Transportation Integrated Search

2010-12-01

Large numbers of reinforced concrete deck girder bridges that were constructed during the interstate system expansion of the 1950s have developed diagonal cracking in the stems. Though compliant with design codes when constructed, many of these bridg...

Repair systems for deteriorated bridge piles : final report.

DOT National Transportation Integrated Search

2017-04-01

The objective of this research project is to develop a durable repair system for deteriorated steel bridge piles that : can be implemented without the need for dewatering. A rigorous survey of the relevant practice nationwide was : conducted to infor...

An expert system as applied to bridges : testing phase : final report.

DOT National Transportation Integrated Search

1991-01-01

This project concludes a four part study regarding the development of an expert system called DOBES, to form conclusions as to the disposition of older bridges. The options include replacement, rehabilitation, improvement, abandonment and routine mai...

Development and performance evaluation of fiber reinforced polymer bridge.

DOT National Transportation Integrated Search

2014-03-01

Fiber reinforced polymers (FRP) have become more popular construction materials in the last decade due to the reduction of : material costs. The installation and performance evaluation of the first FRP-wrapped balsa wood bridge in Louisiana is descri...

Design and construction guidelines for strengthening bridges using fiber reinforced polymers (FRP).

DOT National Transportation Integrated Search

2014-09-01

This research concerns the development of guidelines : for the design and use of externally-bonded FRP : strengthening systems on bridges in Michigan. Si : x representative international FRP-related guidelines : were analyzed and compared for applica...

Modernizing bridge safety inspection with process improvement and digital assistance.

DOT National Transportation Integrated Search

2004-01-01

This research effort was developed to record and analyze the Virginia Department of Transportation (VDOT) bridge/structure inspection processes as an aid to modernizing and automating these inspection processes through the use of mobile personal comp...

The rideability of a deflected bridge approach slab.

DOT National Transportation Integrated Search

2009-11-01

This report presents the findings associated with the development of a new pavement roughness index : called the Posted Speed Localized Roughness Index (LRIPS) that can be used to rate the ride quality on : bridge approach slabs. Currently establishe...

Field evaluation of thermographic bridge concrete inspection techniques.

DOT National Transportation Integrated Search

2013-02-01

The goal of this research is to develop new technologies for the condition assessment of concrete to help ensure bridge safety and improve the effectiveness of maintenance and repair. : The objectives of the research are to: : Quantify the capabi...

Brittle-ductile transition of steel bridges, volume I : final report.

DOT National Transportation Integrated Search

1990-05-01

The transition behavior of bridge steels and weldments largely determines the ir toughness under : service loading rates and temperatures. Two aspects of the transition were investigated in this : project: The first was to develop a better understand...

Numerical simulation of CFRP-repaired reinforced concrete columns.

DOT National Transportation Integrated Search

2014-07-01

The overarching goal of this study was to investigate the influence of repair to individual reinforced concrete bridge columns on the : post-repair seismic performance of the bridge system. A method was developed to rapidly repair an earthquake-damag...

Thermal response of a highly skewed integral bridge.

DOT National Transportation Integrated Search

2012-06-01

The purpose of this study was to conduct a field evaluation of a highly skewed semi-integral bridge in order to provide : feedback regarding some of the assumptions behind the design guidelines developed by the Virginia Department of : Transportation...

Development of precast bridge deck overhang system : technical report.

DOT National Transportation Integrated Search

2011-07-01

The implementation of full-depth, precast overhang panel systems has the potential to improve constructability, : productivity, and make bridges more economical. Initial testing and analyses reported in the 0-6100-2 report resulted in : a design that...

Tool for analysis of early age transverse cracking of composite bridge decks.

DOT National Transportation Integrated Search

2011-08-29

"Executive Summary: Computational methods and associated software were developed : to compute stresses in HP concrete composite bridge decks due to temperature, shrinkage, and : vehicle loading. The structural analysis program uses a layered finite e...

Multimedia package for LRFD concrete bridge design.

DOT National Transportation Integrated Search

2009-02-01

This Project developed a Load and Resistance Factor Design (LRFD) multimedia package to provide a practical introduction and an in-depth understanding of the technological advances in the design of concrete bridges. This package can be used to train ...

The rideability of a deflected bridge approach slab : research project capsule.

DOT National Transportation Integrated Search

2011-08-01

The Localized Roughness Index (LRI) is a parameter that was developed at the Louisiana : Transportation Research Center (LTRC) to quantify localized pavement distresses, such as : pavement surface dips and bumps, concrete slab joint faulting, bridge-...

Procedures for scour assessments at bridges in Pennsylvania

USGS Publications Warehouse

Cinotto, Peter J.; White, Kirk E.

2000-01-01

Scour is the process and result of flowing water eroding the bed and banks of a stream. Scour at nearly 14,300 bridges(1) spanning water, and the stability of river and stream channels in Pennsylvania, are being assessed by the U.S. Geological Survey (USGS) in cooperation with the Pennsylvania Department of Transportation (PennDOT). Procedures for bridge-scour assessments have been established to address the needs of PennDOT in meeting a 1988 Federal Highway Administration mandate requiring states to establish a program to assess all public bridges over water for their vulnerability to scour. The procedures also have been established to help develop an understanding of the local and regional factors that affect scour and channel stability. This report describes procedures for the assessment of scour at all bridges that are 20 feet or greater in length that span water in Pennsylvania. There are two basic types of assessment: field-viewed bridge site assessments, for which USGS personnel visit the bridge site, and office-reviewed bridge site assessments, for which USGS personnel compile PennDOT data and do not visit the bridge site. Both types of assessments are primarily focused at assisting PennDOT in meeting the requirements of the Federal Highway Administration mandate; however, both assessments include procedures for the collection and processing of ancillary data for subsequent analysis. Date of bridge construction and the accessibility of the bridge substructure units for inspection determine which type of assessment a bridge receives. A Scour-Critical Bridge Indicator Code and a Scour Assessment Rating are computed from selected collected and compiled data. PennDOT personnel assign the final Scour-Critical Bridge Indicator Code and a Scour Assessment Rating on the basis of their review of all data. (1)Words presented in bold type are defined in the Glossary section of this report.

Recent advances in the development of a self-powered wireless sensor network for structural health prognosis

NASA Astrophysics Data System (ADS)

Godinez-Azcuaga, Valery F.; Inman, Daniel J.; Ziehl, Paul H.; Giurgiutiu, Victor; Nanni, Antonio

2011-04-01

This paper presents the most recent advances in the development of a self powered wireless sensor network for steel and concrete bridges monitoring and prognosis. This five-year cross-disciplinary project includes development and deployment of a 4-channel acoustic emission wireless node powered by structural vibration and wind energy harvesting modules. In order to accomplish this ambitious goal, the project includes a series of tasks that encompassed a variety of developments such as ultra low power AE systems, energy harvester hardware and especial sensors for passive and active acoustic wave detection. Key studies on acoustic emission produced by corrosion on reinforced concrete and by crack propagation on steel components to develop diagnosis tools and models for bridge prognosis are also a part of the project activities. It is important to mention that the impact of this project extends beyond the area of bridge health monitoring. Several wireless prototype nodes have been already requested for applications on offshore oil platforms, composite ships, combat deployable bridges and wind turbines. This project was awarded to a joint venture formed by Mistras Group Inc, Virginia Tech, University of South Carolina and University of Miami and is sponsored through the NIST-TIP Grant #70NANB9H007.

Probabilistic Fatigue Life Updating for Railway Bridges Based on Local Inspection and Repair.

PubMed

Lee, Young-Joo; Kim, Robin E; Suh, Wonho; Park, Kiwon

2017-04-24

Railway bridges are exposed to repeated train loads, which may cause fatigue failure. As critical links in a transportation network, railway bridges are expected to survive for a target period of time, but sometimes they fail earlier than expected. To guarantee the target bridge life, bridge maintenance activities such as local inspection and repair should be undertaken properly. However, this is a challenging task because there are various sources of uncertainty associated with aging bridges, train loads, environmental conditions, and maintenance work. Therefore, to perform optimal risk-based maintenance of railway bridges, it is essential to estimate the probabilistic fatigue life of a railway bridge and update the life information based on the results of local inspections and repair. Recently, a system reliability approach was proposed to evaluate the fatigue failure risk of structural systems and update the prior risk information in various inspection scenarios. However, this approach can handle only a constant-amplitude load and has limitations in considering a cyclic load with varying amplitude levels, which is the major loading pattern generated by train traffic. In addition, it is not feasible to update the prior risk information after bridges are repaired. In this research, the system reliability approach is further developed so that it can handle a varying-amplitude load and update the system-level risk of fatigue failure for railway bridges after inspection and repair. The proposed method is applied to a numerical example of an in-service railway bridge, and the effects of inspection and repair on the probabilistic fatigue life are discussed.

Probabilistic Fatigue Life Updating for Railway Bridges Based on Local Inspection and Repair

PubMed Central

Lee, Young-Joo; Kim, Robin E.; Suh, Wonho; Park, Kiwon

2017-01-01

Railway bridges are exposed to repeated train loads, which may cause fatigue failure. As critical links in a transportation network, railway bridges are expected to survive for a target period of time, but sometimes they fail earlier than expected. To guarantee the target bridge life, bridge maintenance activities such as local inspection and repair should be undertaken properly. However, this is a challenging task because there are various sources of uncertainty associated with aging bridges, train loads, environmental conditions, and maintenance work. Therefore, to perform optimal risk-based maintenance of railway bridges, it is essential to estimate the probabilistic fatigue life of a railway bridge and update the life information based on the results of local inspections and repair. Recently, a system reliability approach was proposed to evaluate the fatigue failure risk of structural systems and update the prior risk information in various inspection scenarios. However, this approach can handle only a constant-amplitude load and has limitations in considering a cyclic load with varying amplitude levels, which is the major loading pattern generated by train traffic. In addition, it is not feasible to update the prior risk information after bridges are repaired. In this research, the system reliability approach is further developed so that it can handle a varying-amplitude load and update the system-level risk of fatigue failure for railway bridges after inspection and repair. The proposed method is applied to a numerical example of an in-service railway bridge, and the effects of inspection and repair on the probabilistic fatigue life are discussed. PMID:28441768

Investigation of the Stability of a Two-Span Bridge with the use of a High-Precision Laser Displacement Sensors

NASA Astrophysics Data System (ADS)

Poddaeva, O.; Churin, P.; Fedosova, A.; Truhanov, S.

2018-03-01

Studies of aerodynamics of bridge structures are an actual problem. Such attention is paid to the study of wind influence on bridge structures not at all by chance; a large number of cases of loss of stability of such structures are known under the influence of wind up to their complete destruction. The development of non-contact systems of measuring equipment allows solving this problem with a high level of accuracy and reliability. This article presents the results of experimental studies of wind impact on a two-span bridge using specialized measuring system based on high-precision laser displacement sensors.

A sustainable dietetics bridging program: development and implementation in Atlantic Canada.

PubMed

Lordly, Daphne; Guy, Jennifer; Barry, Paula; Garus, Jennifer

2014-01-01

A provincial focus on immigration and improved foreign credential recognition has led to an investigation of best practices and subsequent recommendations for the development and implementation of a sustainable university-based bridging program for internationally educated dietitians in Atlantic Canada. Data were collected from various sources and used to inform program decisions and direction. An advisory framework was established through a core group representing dietetics education and regulation and internationalization. Subsequently, a key stakeholder group was formed. As a result of this collaboration and research, a dietetics bridging framework was developed and a program pilot tested. Lessons learned may inform similar endeavours and highlight the importance of collaborative leadership and collaboration among multiple stakeholders, and of creatively addressing program sustainability issues while keeping learners (internationally educated dietitians) at the centre.

The state of the art of the development of SMES for bridging instantaneous voltage dips in Japan

NASA Astrophysics Data System (ADS)

Nagaya, Shigeo; Hirano, Naoki; Katagiri, Toshio; Tamada, Tsutomu; Shikimachi, Koji; Iwatani, Yu; Saito, Fusao; Ishii, Yusuke

2012-12-01

Development of apparatuses for protecting industrial facilities such as semiconductor plants or information industries from instantaneous voltage dips, which requires very large output power, has been expected. A Superconducting magnetic energy storage system (SMES), one of such apparatus, consists of superconducting magnets that must withstand high voltage during operation and require high reliability. We have already development of SMES using conventional superconducting coils and done the field test of the SMES for bridging instantaneous voltage dips. After field test, the commercial SMES for instantaneous voltage dips is working there. Since field test has started, we have confirmed nearly 40 operations, and all have succeeded. In 2011, three commercial SMES units for bridging instantaneous voltage dips are operating in Japan.

Skin bridge versus rod colostomy in children - comparison between complications.

PubMed

Askarpour, Shahnam; Peyvasteh, Mehran; Changai, Bahram; Javaherizadeh, Hazhir

2012-10-01

Due to economic problems, sigmoid loop colostomy using glass rod may cause problems for our patients for finding glass rod and several visits. The aim of the study was to compare rod versus skin bridge colostomy. In this study, 42 cases who are candidate for colostomy were included. Cases were randomly placed in skin bridge and rod colostomy group. Independent sample t-test and Chi-square were used for comparison. SPSS version 16.0 (SPSS Inc, Chicago, IL, USA) was used for analysis. Of 42 cases, 20 were male and 22 were female. Hirschsprung's disease was the indication of colostomy in 33 cases. In nine cases, imperforate anus was the indication of colostomy. Mean time of surgery was 79.4 and 82.5 minute for the rod and skin bridge group respectively (P>0.05). Retraction was seen in 2 case of rod group, and no case of skin bridge group. Prolapse was seen in 2 (9.5%) case of rod group and 1(4.7%) case in skin bridge. There were no reports of necrosis, stenosis, and hernia in both groups. In the skin bridge group the rates of complications were lower but the groups are too small for statistical analysis. Colostomy with a skin bridge method may decrease number of revision and expenses and may be appropriate option. Sigmoid loop colostomy using skin bridge flap may be appropriate choice in developing country. Another study with more samples is recommended to better comparison of Skin Bridge versus rod colostomy.

Cal-Bridge and CAMPARE: Engaging Underrepresented Students in Physics and Astronomy

NASA Astrophysics Data System (ADS)

Rudolph, Alexander L.; Cal-Bridge and CAMPARE Teams

2018-01-01

We describe two programs, Cal-Bridge and CAMPARE, with the common mission of increasing participation of groups traditionally underrepresented in astronomy, through summer research opportunities, in the case of CAMPARE, scholarships in the case of Cal-Bridge, and significant mentoring in both programs, creating a national impact on their numbers successfully pursuing a PhD in the field.In 8 years, the CAMPARE program has sent 112 students, >80% from underrepresented groups, to conduct summer research at one of 14 major research institutions throughout the country. Of the CAMPARE scholars who have graduated with a Bachelor’s degree, almost two-thirds (65%) have completed or are pursuing graduate education in physics, astronomy, or a related field, at institutions including UCLA, UC Riverside, UC Irvine, UC Santa Barbara, USC, Stanford, Univ. of Arizona, Univ. of Washington, Univ. of Rochester, Michigan State Univ., Georgia Tech, Georgia State Univ., Kent State, Indiana Univ., Univ. of Oregon, Syracuse Univ., Montana State Univ., and the Fisk-Vanderbilt Master’s-to-PhD program.Now entering its fourth year, the Cal-Bridge program is a CSU-UC Bridge program comprised of >140 physics and astronomy faculty from 9 University of California (UC), 15 California State University (CSU), and 30 California Community College (CCC) campuses throughout California. In the first four years, 34 Cal-Bridge Scholars have been selected, including 22 Hispanic, 3 African-American and 13 women students, 10 of whom are from URM groups. Thirty (30) of the 34 Cal-Bridge Scholars are first generation college students. In the last two years, 11 of 13 Cal-Bridge Scholars have begun PhD programs in physics or astronomy at top PhD programs nationally. Three (3) of these 11 scholars have won NSF Graduate Research Fellowships; one more received an Honorable Mention. The next cohort applies this fall.Cal-Bridge provides much deeper mentoring and professional development experiences over the last two years of undergraduate and first year of graduate school to students from this diverse network of higher education institutions. Cal-Bridge Scholars benefit from substantial financial support, intensive, joint mentoring by CSU and UC faculty, professional development workshops, and exposure to research opportunities at the participating UC campuses.

SBION: A Program for Analyses of Salt-Bridges from Multiple Structure Files.

PubMed

Gupta, Parth Sarthi Sen; Mondal, Sudipta; Mondal, Buddhadev; Islam, Rifat Nawaz Ul; Banerjee, Shyamashree; Bandyopadhyay, Amal K

2014-01-01

Salt-bridge and network salt-bridge are specific electrostatic interactions that contribute to the overall stability of proteins. In hierarchical protein folding model, these interactions play crucial role in nucleation process. The advent and growth of protein structure database and its availability in public domain made an urgent need for context dependent rapid analysis of salt-bridges. While these analyses on single protein is cumbersome and time-consuming, batch analyses need efficient software for rapid topological scan of a large number of protein for extracting details on (i) fraction of salt-bridge residues (acidic and basic). (ii) Chain specific intra-molecular salt-bridges, (iii) inter-molecular salt-bridges (protein-protein interactions) in all possible binary combinations (iv) network salt-bridges and (v) secondary structure distribution of salt-bridge residues. To the best of our knowledge, such efficient software is not available in public domain. At this juncture, we have developed a program i.e. SBION which can perform all the above mentioned computations for any number of protein with any number of chain at any given distance of ion-pair. It is highly efficient, fast, error-free and user friendly. Finally we would say that our SBION indeed possesses potential for applications in the field of structural and comparative bioinformatics studies. SBION is freely available for non-commercial/academic institutions on formal request to the corresponding author (akbanerjee@biotech.buruniv.ac.in).

Random vibration analysis of train-bridge under track irregularities and traveling seismic waves using train-slab track-bridge interaction model

NASA Astrophysics Data System (ADS)

Zeng, Zhi-Ping; Zhao, Yan-Gang; Xu, Wen-Tao; Yu, Zhi-Wu; Chen, Ling-Kun; Lou, Ping

2015-04-01

The frequent use of bridges in high-speed railway lines greatly increases the probability that trains are running on bridges when earthquakes occur. This paper investigates the random vibrations of a high-speed train traversing a slab track on a continuous girder bridge subjected to track irregularities and traveling seismic waves by the pseudo-excitation method (PEM). To derive the equations of motion of the train-slab track-bridge interaction system, the multibody dynamics and finite element method models are used for the train and the track and bridge, respectively. By assuming track irregularities to be fully coherent random excitations with time lags between different wheels and seismic accelerations to be uniformly modulated, non-stationary random excitations with time lags between different foundations, the random load vectors of the equations of motion are transformed into a series of deterministic pseudo-excitations based on PEM and the wheel-rail contact relationship. A computer code is developed to obtain the time-dependent random responses of the entire system. As a case study, the random vibration characteristics of an ICE-3 high-speed train traversing a seven-span continuous girder bridge simultaneously excited by track irregularities and traveling seismic waves are analyzed. The influence of train speed and seismic wave propagation velocity on the random vibration characteristics of the bridge and train are discussed.

Performance enhancement of bridge bracing under service and extreme loads.

DOT National Transportation Integrated Search

2010-12-01

The purpose of this study was to develop and demonstrate the concept of retrofitting bridge brace elements with fiber reinforced composites in order to provide restraint against buckling. The advanced materials consisted of a combination of fiber rei...

Development of a TL-3 deep beam tubular backup bridge rail.

DOT National Transportation Integrated Search

2010-12-01

The objective of this study is to investigate the performance of the Ohio Department of Transportation (ODOT) Deep Beam bridge rail system per the National Cooperative Highway Research Program (NCHRP) Report 350 TL-3. Analytical study, computer simul...

Bridging Disciplinary Boundaries

ERIC Educational Resources Information Center

Mei, Linda

2009-01-01

Interdisciplinary education promotes the unity of knowledge by bridging the cultural divide between the social constructs of disciplines and encourages the development of knowledge to enhance society. As an inquiry-based and relevant approach that expands and advances knowledge, interdisciplinary education facilitates creativity and flexibility,…

An industrialized construction approach to concrete superstructures for bridges.

DOT National Transportation Integrated Search

1974-01-01

The objective of this study was to develop drawings for a specific site or sites that incorporated the best concepts of industrialized bridge superstructure construction, that is, great emphasis was placed upon the use of modular design and assembly ...

Steel bridge fabrication technologies in Europe and Japan

DOT National Transportation Integrated Search

2001-03-01

The objective of this scanning tour was to conduct a broad overview of newly developed manufacturing techniques that are in use abroad for steel bridge fabrication and erection. The trip focused on the role of steel production, design, innovation, an...

Structural design guidelines for concrete bridge decks reinforced with corrosion-resistant reinforcing bars.

DOT National Transportation Integrated Search

2014-10-01

This research program develops and validates structural design guidelines and details for concrete bridge decks with : corrosion-resistant reinforcing (CRR) bars. A two-phase experimental program was conducted where a control test set consistent : wi...

Integration of bridge damage detection concepts and components, volume III : wireless bridge monitoring hardware.

DOT National Transportation Integrated Search

2013-10-01

In this work, a previously developed structural health monitoring (SHM) system was advanced toward a ready-for-implementation : system. Improvements were made with respect to automated data reduction/analysis, data acquisition hardware, sensor types,...

Retrofit of existing statewide Louisiana safety walk bridge barrier railing systems : research project capsule.

DOT National Transportation Integrated Search

2016-07-01

Currently, the Louisiana Department of Transportation and Development (DOTD) : maintains approximately 200 miles of concrete safety walk barrier railing systems on : its bridges. Some of these vintage systems do not meet the current crash performance...

The development of crashworthy rails for fiber reinforced polymer honeycomb bridge deck system.

DOT National Transportation Integrated Search

2015-07-01

Fiber reinforced polymer (FRP) honeycomb panels offer an efficient and rapid replacement to : concrete decks. The system consists of FRP honeycomb sandwich panels with adequate guardrails. Although : FRP bridge deck panels have already been designed ...

Performance of a skewed semi-integral bridge : volume 1 : field monitoring.

DOT National Transportation Integrated Search

2008-01-01

This project was developed to enhance the Virginia Department of Transportation's (VDOT) in-house expertise in the design of integral bridges and to provide a resource for consultants performing design work for VDOT. It involved extensive field monit...

The development of crashworthy rails for fiber reinforced polymer honeycomb bridge deck system : [summary].

DOT National Transportation Integrated Search

2015-07-01

Fiber reinforced polymer (FRP) honeycomb panels offer an efficient and rapid : replacement to concrete decks. The system consists of FRP honeycomb sandwich panels : with adequate guardrails. Although FRP bridge deck panels have already been designed ...

Enhancement of welded steel bridge girders susceptible to distortion-induced fatigue.

DOT National Transportation Integrated Search

2014-10-01

The goal of this study was to develop and evaluate the performance of retrofit techniques for existing steel : bridges that have already sustained damage due to distortion-induced fatigue, or are anticipated to experience : distortion-induced fatigue...

Quality control and in-service inspection technology for hybrid-composite girder bridges.

DOT National Transportation Integrated Search

2014-08-01

This report describes efforts to develop quality control tools and in-service inspection technologies for the fabrication and construction of Hybrid Composite Beams (HCBs). HCBs are a new bridge technology currently being evaluated by the Missouri De...

Field demonstration of new bridge approach slab designs and performance.

DOT National Transportation Integrated Search

2014-06-01

The Louisiana Department of Transportation and Development (DOTD) has initiated a major effort to minimize the bridge end bump problem associated : with differential settlement. As a result, a new design for the approach slab was proposed, which requ...

Shear in high strength concrete bridge girders : technical report.

DOT National Transportation Integrated Search

2013-04-01

Prestressed Concrete (PC) I-girders are used extensively as the primary superstructure components in Texas highway bridges. : A simple semi-empirical equation was developed at the University of Houston (UH) to predict the shear strength of PC I-girde...

Safer bridge railings, volume 1 summary report.

DOT National Transportation Integrated Search

1984-06-01

This study consisted of strength analyses of five in-service bridge railing systems, thirty full-scale vehicle crash tests on those railing systems and on a load measuring wall, the development of recommended design guidelines and deve1opment of reco...

Implementation of high performance concrete in Louisiana bridges : interim report.

DOT National Transportation Integrated Search

1998-02-01

The report contains a research plan to assist in the implementation of high performance concrete in the Charenton Canal Bridge in Louisiana. The research involves a literature review, plan review, development of a quality control program for the conc...

Assessment of weathering steel bridge performance in Iowa and development of inspection and maintenance techniques.

DOT National Transportation Integrated Search

2013-02-01

Weathering steel is commonly used as a cost-effective alternative for bridge superstructures, as the costs and environmental : impacts associated with the maintenance/replacement of paint coatings are theoretically eliminated. The performance of : we...

Transverse joint configuration development and testing for a modular bridge deck replacement system.

DOT National Transportation Integrated Search

2011-03-01

According to the 2009 Report Card for Americas Infrastructure, one in four of the nations bridges are listed as : structurally deficient of functionally obsolete, establishing a dire need for new and innovative repair and replacement : techniqu...

Laboratory investigation of grouted coupler connection details for ABC bridge projects : [tech transfer summary].

DOT National Transportation Integrated Search

2015-08-01

Advancements and increased use of accelerated bridge construction (ABC) : often result in the use of newly developed, or modified, technologies and/or : construction techniques that are sometimes untested in this new application. : For designers and ...

Simulation, Model Verification and Controls Development of Brayton Cycle PM Alternator: Testing and Simulation of 2 KW PM Generator with Diode Bridge Output

NASA Technical Reports Server (NTRS)

Stankovic, Ana V.

2003-01-01

Professor Stankovic will be developing and refining Simulink based models of the PM alternator and comparing the simulation results with experimental measurements taken from the unit. Her first task is to validate the models using the experimental data. Her next task is to develop alternative control techniques for the application of the Brayton Cycle PM Alternator in a nuclear electric propulsion vehicle. The control techniques will be first simulated using the validated models then tried experimentally with hardware available at NASA. Testing and simulation of a 2KW PM synchronous generator with diode bridge output is described. The parameters of a synchronous PM generator have been measured and used in simulation. Test procedures have been developed to verify the PM generator model with diode bridge output. Experimental and simulation results are in excellent agreement.

Awareness campaign.

PubMed

2007-01-01

LifeBridge Health developed and implemented an awareness campaign to generate buzz about the breast cancer services at the Alvin & Lois Lapidus Cancer Institute of LifeBridge Health and the Herman & Walter Samuelson Breast Cancer Care Center at Northwest Hospital Center. With the help of talented local breast cancer survivors, celebrities, fashion designers, and artists, LifeBridge Health created a campaign, including an interactive Web site, public relations outreach, and a unique event in October 2006 that featured a collection of hand-made decorated bras.

IPACS Electronics: Comments on the Original Design and Current Efforts at Langley Research Center

NASA Technical Reports Server (NTRS)

Gowdey, J. C.

1983-01-01

The development of the integrated power altitude control system (IPACS) is described. The power bridge was fabricated, and all major parts are in hand. The bridge was tested with a 1/4 HP motor for another program. The PWM, Control Logic, and upper bridge driver power supply are breadboarded and are debugged prior to starting testing on a passive load. The Hall sensor circuit for detecting rotor position is in design.

Space Paint

NASA Technical Reports Server (NTRS)

1976-01-01

Developed at Goddard, this improved inorganic paint may help protect coastal bridges subject to extreme corrosion from seawater spray. Potassium silicate formulated into a thin waterbase binder that sprays easily, adheres readily, and can be heavily loaded with zinc particles to provide uniform coverage in a single coat. Stanford Research Institute has measured an annual market in excess of $2 billion in painting highway bridges, utility pipelines, nuclear reactors, and railcar hoppers. Other suitable markets include offshore drilling facilities, railroad bridges, and ships.

Development and Evaluation of the Stingray, an Amphibious Maritime Interdiction Operations Unmanned Ground Vehicle

DTIC Science & Technology

2014-05-01

of Ships], Charles Griffin and Company, London, 246-261 (1908). [6] Volpich, H. & Bridge, I . C., “Paddle Wheels Pt 1: Preliminary Model Experiments...Transactions of the Institution of Engineers and Shipbuilders in Scotland, 327-380 (1955). [7] Volpich, H. & Bridge, I . C., “Paddle Wheels...Bridge, I . C., “Paddle Wheels Pt III: Ship/Model Correlation,” Transactions of the Institution of Engineers and Shipbuilders in Scotland, 512-550

Elimination of deck joints using a corrosion resistant FRP approach

NASA Astrophysics Data System (ADS)

Aleti, Ashok Reddy

The research presented herein describes the development of durable link slabs for jointless bridge decks based on using FRP grid for reinforcement. Specifically, the ductility of the FRP material was utilized to accommodate bridge deck deformations imposed by girder deflection, temperature variations, and concrete shrinkage. It would also provide a solution to a number of deterioration problems associated with bridge deck joints. The design concept of the link slabs was then examined to form the basis of design for FRP grid link slabs. Improved design of FRP grid link slab/concrete deck slab interface was confirmed in the numerical analysis. The mechanical properties between the FRP grid and concrete were evaluated. The behavior of the link slab was investigated and confirmed for durability. The results indicated that the technique would allow simultaneous achievement of structural need (lower flexural stiffness of the link slab approaching the behavior of a hinge) and durability need of the link slab. Also, the development length results confirm that the bond between the FRP grid and the concrete was highly improved. The overall investigation supports the contention that durable jointless concrete bridge decks may be designed and constructed with FRP grid link slabs. It is recommended that the link slab technique be used during new construction of the bridge decks and in repair and retrofit of the bridge decks.

Method for rapid estimation of scour at highway bridges based on limited site data

USGS Publications Warehouse

Holnbeck, S.R.; Parrett, Charles

1997-01-01

Limited site data were used to develop a method for rapid estimation of scour at highway bridges. The estimates can be obtained in a matter of hours rather than several days as required by more-detailed methods. Such a method is important because scour assessments are needed to identify scour-critical bridges throughout the United States. Using detailed scour-analysis methods and scour-prediction equations recommended by the Federal Highway Administration, the U.S. Geological Survey, in cooperation with the Montana Department of Transportation, obtained contraction, pier, and abutment scour-depth data for sites from 10 States.The data were used to develop relations between scour depth and hydraulic variables that can be rapidly measured in the field. Relations between scour depth and hydraulic variables, in the form of envelope curves, were based on simpler forms of detailed scour-prediction equations. To apply the rapid-estimation method, a 100-year recurrence interval peak discharge is determined, and bridge- length data are used in the field with graphs relating unit discharge to velocity and velocity to bridge backwater as a basis for estimating flow depths and other hydraulic variables that can then be applied using the envelope curves. The method was tested in the field. Results showed good agreement among individuals involved and with results from more-detailed methods. Although useful for identifying potentially scour-critical bridges, themethod does not replace more-detailed methods used for design purposes. Use of the rapid- estimation method should be limited to individuals having experience in bridge scour, hydraulics, and flood hydrology, and some training in use of the method.

Bridging the gap between research and marketing: private and public partnerships

NASA Astrophysics Data System (ADS)

Shtern, Faina

1995-10-01

The goal of this paper is to examine the importance of private and public partnerships in bridging the gap between research and marketing and their implications for the development of a national policy in research support in imaging science and technologies. Breast cancer imaging will serve as a case study for the development of collaborations between government agencies, academic community, and industry as the means to facilitate development, evaluation, and implementation of promising diagnostic technologies.

Wind-Driven Formation of Ice Bridges in Straits.

PubMed

Rallabandi, Bhargav; Zheng, Zhong; Winton, Michael; Stone, Howard A

2017-03-24

Ice bridges are static structures composed of tightly packed sea ice that can form during the course of its flow through a narrow strait. Despite their important role in local ecology and climate, the formation and breakup of ice bridges is not well understood and has proved difficult to predict. Using long-wave approximations and a continuum description of sea ice dynamics, we develop a one-dimensional theory for the wind-driven formation of ice bridges in narrow straits, which is verified against direct numerical simulations. We show that for a given wind stress and minimum and maximum channel widths, a steady-state ice bridge can only form beyond a critical value of the thickness and the compactness of the ice field. The theory also makes quantitative predictions for ice fluxes, which are particularly useful to estimate the ice export associated with the breakup of ice bridges. We note that similar ideas are applicable to dense granular flows in confined geometries.

Estimation of potential bridge scour at bridges on state routes in South Dakota, 2003-07

USGS Publications Warehouse

Thompson, Ryan F.; Fosness, Ryan L.

2008-01-01

Flowing water can erode (scour) soils and cause structural failure of a bridge by exposing or undermining bridge foundations (abutments and piers). A rapid scour-estimation technique, known as the level-1.5 method and developed by the U.S. Geological Survey, was used to evaluate potential scour at bridges in South Dakota in a study conducted in cooperation with the South Dakota Department of Transportation. This method was used during 2003-07 to estimate scour for the 100-year and 500-year floods at 734 selected bridges managed by the South Dakota Department of Transportation on State routes in South Dakota. Scour depths and other parameters estimated from the level-1.5 analyses are presented in tabular form. Estimates of potential contraction scour at the 734 bridges ranged from 0 to 33.9 feet for the 100-year flood and from 0 to 35.8 feet for the 500-year flood. Abutment scour ranged from 0 to 36.9 feet for the 100-year flood and from 0 to 45.9 feet for the 500-year flood. Pier scour ranged from 0 to 30.8 feet for the 100-year flood and from 0 to 30.7 feet for the 500-year flood. The scour depths estimated by using the level-1.5 method can be used by the South Dakota Department of Transportation and others to identify bridges that may be susceptible to scour. Scour at 19 selected bridges also was estimated by using the level-2 method. Estimates of contraction, abutment, and pier scour calculated by using the level-1.5 and level-2 methods are presented in tabular and graphical formats. Compared to level-2 scour estimates, the level-1.5 method generally overestimated scour as designed, or in a few cases slightly underestimated scour. Results of the level-2 analyses were used to develop regression equations for change in head and average velocity through the bridge opening. These regression equations derived from South Dakota data are compared to similar regression equations derived from Montana and Colorado data. Future level-1.5 scour investigations in South Dakota may benefit from the use of these South Dakota-specific regression equations for estimating change in stream head and average velocity at the bridge.

Algorithms for highway-speed acoustic impact-echo evaluation of concrete bridge decks

NASA Astrophysics Data System (ADS)

Mazzeo, Brian A.; Guthrie, W. Spencer

2018-04-01

A new acoustic impact-echo testing device has been developed for detecting and mapping delaminations in concrete bridge decks at highway speeds. The apparatus produces nearly continuous acoustic excitation of concrete bridge decks through rolling mats of chains that are placed around six wheels mounted to a hinged trailer. The wheels approximately span the width of a traffic lane, and the ability to remotely lower and raise the apparatus using a winch system allows continuous data collection without stationary traffic control or exposure of personnel to traffic. Microphones near the wheels are used to record the acoustic response of the bridge deck during testing. In conjunction with the development of this new apparatus, advances in the algorithms required for data analysis were needed. This paper describes the general framework of the algorithms developed for converting differential global positioning system data and multi-channel audio data into maps that can be used in support of engineering decisions about bridge deck maintenance, rehabilitation, and replacement (MR&R). Acquisition of position and audio data is coordinated on a laptop computer through a custom graphical user interface. All of the streams of data are synchronized with the universal computer time so that audio data can be associated with interpolated position information through data post-processing. The audio segments are individually processed according to particular detection algorithms that can adapt to variations in microphone sensitivity or particular chain excitations. Features that are greater than a predetermined threshold, which is held constant throughout the analysis, are then subjected to further analysis and included in a map that shows the results of the testing. Maps of data collected on a bridge deck using the new acoustic impact-echo testing device at different speeds ranging from approximately 10 km/h to 55 km/h indicate that the collected data are reasonably repeatable. Use of the new acoustic impact-echo testing device is expected to enable more informed decisions about MR&R of concrete bridge decks.

Air-bridged Ohmic contact on vertically aligned si nanowire arrays: application to molecule sensors.

PubMed

Han, Hee; Kim, Jungkil; Shin, Ho Sun; Song, Jae Yong; Lee, Woo

2012-05-02

A simple, cost-effective, and highly reliable method for constructing an air-bridged electrical contact on large arrays of vertically aligned nanowires was developed. The present method may open up new opportunities for developing advanced nanowire-based devices for energy harvest and storage, power generation, and sensing applications. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The Rainbow Bridge Metaphor as a Tool for Developing Accessible E-Learning Practices in Higher Education

ERIC Educational Resources Information Center

Seale, Jane K.

2006-01-01

This paper explores the extent to which existing accessibility metaphors can help to develop our conceptualizations of accessible e-­learning practice in higher education and outlines a proposal for a new rainbow bridge metaphor for accessible e­-learning practice. The need for a metaphor that reflects in more depth what we are beginning to…

Aesthetic coatings for concrete bridge components

NASA Astrophysics Data System (ADS)

Kriha, Brent R.

This thesis evaluated the durability and aesthetic performance of coating systems for utilization in concrete bridge applications. The principle objectives of this thesis were: 1) Identify aesthetic coating systems appropriate for concrete bridge applications; 2) Evaluate the performance of the selected systems through a laboratory testing regimen; 3) Develop guidelines for coating selection, surface preparation, and application. A series of site visits to various bridges throughout the State of Wisconsin provided insight into the performance of common coating systems and allowed problematic structural details to be identified. To aid in the selection of appropriate coating systems, questionnaires were distributed to coating manufacturers, bridge contractors, and various DOT offices to identify high performing coating systems and best practices for surface preparation and application. These efforts supplemented a literature review investigating recent publications related to formulation, selection, surface preparation, application, and performance evaluation of coating materials.

Flood scour monitoring system using fiber Bragg grating sensors

NASA Astrophysics Data System (ADS)

Lin, Yung Bin; Lai, Jihn Sung; Chang, Kuo Chun; Li, Lu Sheng

2006-12-01

The exposure and subsequent undermining of pier/abutment foundations through the scouring action of a flood can result in the structural failure of a bridge. Bridge scour is one of the leading causes of bridge failure. Bridges subject to periods of flood/high flow require monitoring during those times in order to protect the traveling public. In this study, an innovative scour monitoring system using button-like fiber Bragg grating (FBG) sensors was developed and applied successfully in the field during the Aere typhoon period in 2004. The in situ FBG scour monitoring system has been demonstrated to be robust and reliable for real-time scour-depth measurements, and to be valid for indicating depositional depth at the Dadu Bridge. The field results show that this system can function well and survive a typhoon flood.

Development of bridge-scour instrumentation for inspection and maintenance personnel

USGS Publications Warehouse

Mueller, David S.; Landers, Mark N.; ,

1993-01-01

Inspecting bridges and monitoring scour during high flow can improve public transportation safety by providing early identification of scour and stream stability problems at bridges. Most bridge-inspection data are collected during low flow, when scour holes may have refilled. More than 25 percent of the States that responded to a questionnaire identified lack of adequate methodology and/or equipment as reasons for not collecting scour data during high-flow conditions. Therefore, the U.S. Geological Survey (USGS), in cooperation with the Federal Highway Administration, has begun to develop instrumentation for measuring scour that could be used by inspection and maintenance personnel during high-flow conditions. A variety of instruments and techniques for measuring scour were tested and evaluated in real-time bridge-scour data-collection studies by the USGS. In the National Scour study, fathometers were found to be superior to sounding weights and will be the primary bed-measuring instrument. The ability of low-cost fathometers and fish finders to locate the bed accurately is being evaluated. Simple and efficient methods for deploying the transducer during floods are also important for a successful measurement. The information and additional testing are being used to design new, portable scour-measuring systems.

Strengthening of bridges by post-tensioning using monostrands in substituted cable ducts

NASA Astrophysics Data System (ADS)

Klusáček, Ladislav; Svoboda, Adam

2017-09-01

Post-tensioning is suitable, reliable and durable method of strengthening existing engineering structures, especially bridges. The high efficiency of post-tensioning can be seen in many applications throughout the world. In this paper the method is extended by a structural system of substituted cable ducts, which allows for significantly widening application of prestressing so it’s convenient mostly for application on beam bridges or slab bridges (built in years 1920 - 1960). The method of substituted cable ducts is based on theoretical knowledge and technical procedures, which were made possible through the development in prestressing systems, particularly the development of prestressing tendons (monostrands) and encased anchorages, as well as progress in drilling technology. This technique is highly recommended due to minimization of interventions into the constructions, unseen method of cable arrangement and hence the absence of impact on appearance, which is appreciated not only in case of valuable historical structures but also in general. It is possible to summarise that posttensioning by monostrands in substituted cable ducts is a highly effective method of strengthening existing bridges in order to increase their load capacities in terms of current traffic load and to extend their service life.

Long-Term Structural Health Monitoring System for a High-Speed Railway Bridge Structure.

PubMed

Ding, You-Liang; Wang, Gao-Xin; Sun, Peng; Wu, Lai-Yi; Yue, Qing

2015-01-01

Nanjing Dashengguan Bridge, which serves as the shared corridor crossing Yangtze River for both Beijing-Shanghai high-speed railway and Shanghai-Wuhan-Chengdu railway, is the first 6-track high-speed railway bridge with the longest span throughout the world. In order to ensure safety and detect the performance deterioration during the long-time service of the bridge, a Structural Health Monitoring (SHM) system has been implemented on this bridge by the application of modern techniques in sensing, testing, computing, and network communication. The SHM system includes various sensors as well as corresponding data acquisition and transmission equipment for automatic data collection. Furthermore, an evaluation system of structural safety has been developed for the real-time condition assessment of this bridge. The mathematical correlation models describing the overall structural behavior of the bridge can be obtained with the support of the health monitoring system, which includes cross-correlation models for accelerations, correlation models between temperature and static strains of steel truss arch, and correlation models between temperature and longitudinal displacements of piers. Some evaluation results using the mean value control chart based on mathematical correlation models are presented in this paper to show the effectiveness of this SHM system in detecting the bridge's abnormal behaviors under the varying environmental conditions such as high-speed trains and environmental temperature.

Intelligent structural health monitoring of vehicular bridges using fiber optic sensors to detect acoustic emission.

DOT National Transportation Integrated Search

2011-01-28

The recent collapse of the I-35W Mississippi River Bridge in Minneapolis has spawned a growing : interest in the development of reliable techniques for evaluating the structural integrity of civil : infrastructure. Current inspection techniques tailo...

Determination of brace forces caused by construction loads and wind loads during bridge construction : [summary].

DOT National Transportation Integrated Search

2014-04-01

Bridges are constructed in stages as pilings, : columns, girders, decks, and other components : are added. At each stage, the structure must be : stable. Girders, which add significant weight to : the developing structure, rest on elastomeric : beari...

Repair of earthquake damaged bridge columns with fractured bars.

DOT National Transportation Integrated Search

2013-07-01

The objective of this study is to repair three, half-scale RC bridge columns that will be tested to failure under slow cyclic loading. : These columns will have fractured longitudinal and transverse steel. The ultimate goal is to develop repair metho...

Stress-corrosion susceptibility of highway bridge construction steels. Phase I

DOT National Transportation Integrated Search

1972-04-01

A catalog of steels used in highway bridge construction has been developed. A state-of-the-art survey on the stress-corrosion susceptibility of these steels has been conducted. The types and concentrations of corrosives that can be experienced in the...

Alternative and cost-effective bridge approach slabs.

DOT National Transportation Integrated Search

2010-10-01

The primary objectives of the proposed project are to investigate the causes for any bumps at the end of the bridge approach slab : and to develop remedial measures or alternative designs for a replacement. It is clear that the problem stems from geo...

Development of an engineered cementitious composite to enhance bridge approach slab durability.

DOT National Transportation Integrated Search

2013-06-01

The strength and durability of highway bridges are two of the key components in maintaining a : high level of freight transportation capacity on the nations highways. : The CFIRE project 04-09 demonstrated the feasibility of a new hybrid engineered...

Asset management program enhancement plan : baseline assessment phases I and II.

DOT National Transportation Integrated Search

2015-09-01

This project resulted in the development of a framework for making asset management decisions on low-volume bridges. The : research focused on low-volume bridges located in the agricultural counties of Iowa because recent research has shown that thes...

Replacing thermal sprayed zinc anodes on cathodically protected steel reinforced concrete bridges.

DOT National Transportation Integrated Search

2011-09-01

This research aimed to address questions underlying the replacement of arc-sprayed zinc anodes on cathodically protected steel reinforced concrete bridges and to develop a protocol to prepare the concrete surface for the new anode, through a combinat...

Replacing thermal sprayed zinc anodes on cathodically protected steel reinforced concrete bridges.

DOT National Transportation Integrated Search

2011-08-01

"This research aimed to address questions underlying the replacement of arc-sprayed zinc anodes on cathodically protected steel reinforced concrete bridges and to develop a protocol to prepare the concrete surface for the new anode, through a combina...

Bridge approach slabs for Missouri DOT looking at alternative and cost efficient approaches.

DOT National Transportation Integrated Search

2010-12-01

The objective of this project is to develop innovative and cost effective structural solutions for the construction of : both new and replacement deteriorated Bridge Approach Slabs (BAS). A cost study and email survey was performed to identify : stat...

Long-term monitoring of the HPC Charenton Canal Bridge : tech summary.

DOT National Transportation Integrated Search

2011-08-01

In 1997, the Louisiana Department of Transportation and Development (LADOTD) began to design the : Charenton Canal Bridge using HPC for both the superstructure and the substructure. As a part of the project, : a research contract was awarded to assis...

Autonomous measurements of bridge pier and abutment scour using motion-sensing radio transmitters.

DOT National Transportation Integrated Search

2010-01-01

Two portable Radio Frequency IDentification (RFID) systems (made by Texas Instruments and HiTAG) were developed and tested for bridge scour monitoring by the Department of Civil and Environmental Engineering at the University of Iowa. Both systems co...

Field validation of a drive-by bridge inspection system with wireless BWIM + NDE devices : final report.

DOT National Transportation Integrated Search

2016-09-01

In this project, researchers developed and performed field validation of a wireless structural sensing system for a variety of bridge response measurements, including strain, acceleration, and displacement. The research team used the wireless strain ...

An adaptive field detection method for bridge scour monitoring using motion-sensing radio transponders (RFIDs).

DOT National Transportation Integrated Search

2014-01-01

A comprehensive field detection method is proposed that is aimed at developing advanced capability for : reliable monitoring, inspection and life estimation of bridge infrastructure. The goal is to utilize Motion-Sensing Radio Transponders (RFIDS) on...

Repairing/strengthening of bridges with post-tensioned FRP strands and performance evaluation.

DOT National Transportation Integrated Search

2008-06-01

The proposed project is to take advantage of some new developments in bridge engineering to apply fiber reinforced polymers (FRP) post-tensioning strands on a selected structure. The use of externally post-tensioned FRP strands to repair/strengthen b...

Impact of overweight vehicles (with heavy axle loads) on bridge deck deterioration.

DOT National Transportation Integrated Search

2012-03-01

Bridge deck slabs develop compressive stresses from global flexural deformation and locally from high-level : wheel loads when it is subjected to overweight trucks. This study quantified the impact of overweight vehicles : with heavy axle loads on br...

Design and Evaluation of Scour for Bridges Using HEC-18 : technical brief.

DOT National Transportation Integrated Search

2017-07-01

This project developed a new approach for evaluating erosive scour at New Jersey bridges over non-tidal waterways. The main deliverable was the Scour Evaluation Model (SEM), which offers new analysis procedures, while still retaining the applicable p...

Two-Electron Transfer Pathways.

PubMed

Lin, Jiaxing; Balamurugan, D; Zhang, Peng; Skourtis, Spiros S; Beratan, David N

2015-06-18

The frontiers of electron-transfer chemistry demand that we develop theoretical frameworks to describe the delivery of multiple electrons, atoms, and ions in molecular systems. When electrons move over long distances through high barriers, where the probability for thermal population of oxidized or reduced bridge-localized states is very small, the electrons will tunnel from the donor (D) to acceptor (A), facilitated by bridge-mediated superexchange interactions. If the stable donor and acceptor redox states on D and A differ by two electrons, it is possible that the electrons will propagate coherently from D to A. While structure-function relations for single-electron superexchange in molecules are well established, strategies to manipulate the coherent flow of multiple electrons are largely unknown. In contrast to one-electron superexchange, two-electron superexchange involves both one- and two-electron virtual intermediate states, the number of virtual intermediates increases very rapidly with system size, and multiple classes of pathways interfere with one another. In the study described here, we developed simple superexchange models for two-electron transfer. We explored how the bridge structure and energetics influence multielectron superexchange, and we compared two-electron superexchange interactions to single-electron superexchange. Multielectron superexchange introduces interference between singly and doubly oxidized (or reduced) bridge virtual states, so that even simple linear donor-bridge-acceptor systems have pathway topologies that resemble those seen for one-electron superexchange through bridges with multiple parallel pathways. The simple model systems studied here exhibit a richness that is amenable to experimental exploration by manipulating the multiple pathways, pathway crosstalk, and changes in the number of donor and acceptor species. The features that emerge from these studies may assist in developing new strategies to deliver multiple electrons in condensed-phase redox systems, including multiple-electron redox species, multimetallic/multielectron redox catalysts, and multiexciton excited states.

Detection and characterization of corrosion of bridge cables by time domain reflectometry

NASA Astrophysics Data System (ADS)

Liu, Wei; Hunsperger, Robert G.; Folliard, Kevin; Chajes, Michael J.; Barot, Jignesh; Jhaveri, Darshan; Kunz, Eric

1999-02-01

In this paper, we develop and demonstrate a nondestructive evaluation technique for corrosion detection of embedded or encased steel cables. This technique utilizes time domain reflectometry (TDR), which has been traditionally used to detect electrical discontinuities in transmission lines. By applying a sensor wire along with the bridge cable, we can model the cable as an asymmetric, twin-conductor transmission line. Physical defects of the bridge cable will change the electromagnetic properties of the line and can be detected by TDR. Furthermore, different types of defects can be modeled analytically, and identified using TDR. TDR measurement results from several fabricated bridge cable sections with built-in defects are reported.

Building Bridges to Integrate Care (BRIDGES): Incubating Health Service Innovation across the Continuum of Care for Patients with Multiple Chronic Conditions.

PubMed

Bhattacharyya, Onil; Schull, Michael; Shojania, Kaveh; Stergiopoulos, Vicky; Naglie, Gary; Webster, Fiona; Brandao, Ricardo; Mohammed, Tamara; Christian, Jennifer; Hawker, Gillian; Wilson, Lynn; Levinson, Wendy

2016-01-01

Integrating care for people with complex needs is challenging. Indeed, evidence of solutions is mixed, and therefore, well-designed, shared evaluation approaches are needed to create cumulative learning. The Toronto-based Building Bridges to Integrate Care (BRIDGES) collaborative provided resources to refine and test nine new models linking primary, hospital and community care. It used mixed methods, a cross-project meta-evaluation and shared outcome measures. Given the range of skills required to develop effective interventions, a novel incubator was used to test and spread opportunities for system integration that included operational expertise and support for evaluation and process improvement.

A Decision Support System for Concrete Bridge Maintenance

NASA Astrophysics Data System (ADS)

Rashidi, Maria; Lemass, Brett; Gibson, Peter

2010-05-01

The maintenance of bridges as a key element in transportation infrastructure has become a major concern for asset managers and society due to increasing traffic volumes, deterioration of existing bridges and well-publicised bridge failures. A pivotal responsibility for asset managers in charge of bridge remediation is to identify the risks and assess the consequences of remediation programs to ensure that the decisions are transparent and lead to the lowest predicted losses in recognized constraint areas. The ranking of bridge remediation treatments can be quantitatively assessed using a weighted constraint approach to structure the otherwise ill-structured phases of problem definition, conceptualization and embodiment [1]. This Decision Support System helps asset managers in making the best decision with regards to financial limitations and other dominant constraints imposed upon the problem at hand. The risk management framework in this paper deals with the development of a quantitative intelligent decision support system for bridge maintenance which has the ability to provide a source for consistent decisions through selecting appropriate remediation treatments based upon cost, service life, product durability/sustainability, client preferences, legal and environmental constraints. Model verification and validation through industry case studies is ongoing.

I-5/Gilman advanced technology bridge project

NASA Astrophysics Data System (ADS)

Lanza di Scalea, Francesco; Karbhari, Vistasp M.; Seible, Frieder

2000-04-01

The UCSD led I-5/Gilman Advanced Technology Bridge Project will design and construct a fully functional traffic bridge of advanced composite materials across Interstate 5 in La Jolla, California. Its objective is to demonstrate the use of advanced composite technologies developed by the aerospace industry in commercial applications to increase the life expectancy of new structures and for the rehabilitation of aging infrastructure components. The structure will be a 450 ft long, 60 ft wide cable-stayed bridge supported by a 150 ft A-frame pylon with two vehicular lanes, two bicycle lanes, pedestrian walkways and utility tunnels. The longitudinal girders and pylon will be carbon fiber shells filled with concrete. The transverse deck system will consist of hollow glass/carbon hybrid tubes and a polypropylene fiber reinforced concrete deck with an arch action. Selected cables will be composite. The bridge's structural behavior will be monitored to determine how advanced composite materials perform in civil infrastructure applications. The bridge will be instrumented to obtain performance and structural health data in real time and, where possible, in a remote fashion. The sensors applied to the bridge will include electrical resistance strain gages, fiberoptic Bragg gratings and accelerometers.

Controlled Blasting for Deconstruction of a Railway Bridge Near Sahibganj

NASA Astrophysics Data System (ADS)

Mandal, S. K.; Ghosh, A. K.; Oraon, S.

2018-06-01

Some of the Indian Railway bridges require reconstruction for electrification and expansion of railway tracks. Dismantling of bridge within time schedule in densely populated area requires controlled and pre-planned blasting methodology for safe pulling down of the structure and quick removal of blasted debris for fast restoration of tracks and smooth plying of trains. The three arched railway bridge (Bridge No. 61) located between Sahibganj and Karamtola cases one such example where the bridge was dismantled and the track was restored within 4 h of blasting, though the stipulated block period for demolition and restoration of tracks was 6 h. The 25.48 m long three-arched bridge was drilled and blasted with 225 number of blastholes (32 mm diameter) and 100 kg explosive (25 mm diameter). Length of blastholes varied between 0.5 and 1.8 m with blast geometry of 0.3-0.35 m burden and 0.33 m spacing. This paper deals with the conceptual and theoretical model developed for identification of the key locations for drilling and implementation of the same. It also discusses about the precautionary measures and the drilling pattern adopted for quick demolition and speedy restoration of tracks.

Controlled Blasting for Deconstruction of a Railway Bridge Near Sahibganj

NASA Astrophysics Data System (ADS)

Mandal, S. K.; Ghosh, A. K.; Oraon, S.

2018-02-01

Some of the Indian Railway bridges require reconstruction for electrification and expansion of railway tracks. Dismantling of bridge within time schedule in densely populated area requires controlled and pre-planned blasting methodology for safe pulling down of the structure and quick removal of blasted debris for fast restoration of tracks and smooth plying of trains. The three arched railway bridge (Bridge No. 61) located between Sahibganj and Karamtola cases one such example where the bridge was dismantled and the track was restored within 4 h of blasting, though the stipulated block period for demolition and restoration of tracks was 6 h. The 25.48 m long three-arched bridge was drilled and blasted with 225 number of blastholes (32 mm diameter) and 100 kg explosive (25 mm diameter). Length of blastholes varied between 0.5 and 1.8 m with blast geometry of 0.3-0.35 m burden and 0.33 m spacing. This paper deals with the conceptual and theoretical model developed for identification of the key locations for drilling and implementation of the same. It also discusses about the precautionary measures and the drilling pattern adopted for quick demolition and speedy restoration of tracks.

Evaluation of bridge decks using non-destructive evaluation (NDE) at near highway speeds for effective asset management - pilot project.

DOT National Transportation Integrated Search

2016-09-29

This project piloted the findings from an initial research and development project pertaining to the detection, : quantification, and visualization of bridge deck distresses through the use of remote sensing techniques, specifically : combining optic...

Remote monitoring of fatigue-sensitive details on bridges : [part I and II].

DOT National Transportation Integrated Search

2015-03-01

Fatigue is one of the most critical problems for steel bridges as well as for any steel structures that needs : to be considered during design and operation. The objectives of this study are to explore monitoring : technologies, and to develop effect...

Development of smart bridge bearings system : a feasibility study : final report.

DOT National Transportation Integrated Search

2005-12-01

The goal of this project has been achieved through three tasks. The main goal of Task I has been : to identify appropriate sensors that have potential for bridge bearings applications. This has been : achieved through the following subtasks and has b...

Pilot installation of a bridge scour monitoring site at FM 1157 Mustang Creek

DOT National Transportation Integrated Search

1999-12-01

A pilot installation was implemented at the Mustang Creek bridge crossing on FM 1157 in the Yoakum District, Jackson County, Texas. This pilot installation was developed in two phases. Phase 1 used a rather limited datalogger that lacked the ability ...

Anchorage zone design for pretensioned precast bulb-T bridge girders in Virginia.

DOT National Transportation Integrated Search

2009-01-01

Precast/prestressed concrete girders are commonly used in bridge construction in the United States. The application and diffusion of the prestress force in a pretensioned girder cause a vertical tension force to develop near the end of the beam. Fiel...

Developing a methodology to inspect and assess conditions of short span structures on county roads in Wyoming.

DOT National Transportation Integrated Search

2015-12-01

Ever since the introduction of the National Bridge Inspection Standards (NBIS) in 1971, there has been a : tremendous amount of effort put into bridge rehabilitation programs and safety inspections. The : Wyoming Department of Transportation (WYDOT) ...

On the spot damage detection methodology for highway bridges during natural crises : tech transfer summary.

DOT National Transportation Integrated Search

2010-07-01

The objective of this work was to develop a : low-cost portable damage detection tool to : assess and predict damage areas in highway : bridges. : The proposed tool was based on standard : vibration-based damage identification (VBDI) : techniques but...

Development of recommended resistance factors for drilled shafts in weak rocks based on o-cell tests.

DOT National Transportation Integrated Search

2010-03-01

From October 1, 2007, the new bridges on federal-aid funded projects are mandated to be designed to meet : American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design : (LRFD) Bridge Design Specificat...

Development of guidelines for incorporation of vertical ground motion effects in seismic design of highway bridges.

DOT National Transportation Integrated Search

2008-05-01

This study was undertaken with the objective of assessing the current provisions in SDC-2006 for incorporating : vertical effects of ground motions in seismic evaluation and design of ordinary highway bridges. A : comprehensive series of simulations ...

Implementation project: strengthening of a bridge near Hondo, Texas using post-installed shear connectors.

DOT National Transportation Integrated Search

2009-03-01

This project was an implementation of research conducted under TxDOT Research Project 0-4124 on the use : of post-installed shear connectors to develop composite action in existing non-composite steel bridge girder : systems. In this implementation s...

High speed ground penetrating radar for road pavement and bridge structural inspection and maintenance : final report.

DOT National Transportation Integrated Search

2016-06-30

The overarching objective of this research is the development of a systematic methodology of employing GPR, including instruments, subsequent data processing and interpretation that can be used regularly as part of a roadway pavement and bridge evalu...

Load rating and FRP retrofitting of bridge abutment timber piles.

DOT National Transportation Integrated Search

2016-05-01

This report details Phase II of the study titled Strengthening of Bridge Wood Piling Retrofits for Moment Resistance. Phase I of the research (project : R27-082) was focused on developing a load rating method for timber piles under eccentric load and...

Real-time stress monitoring of highway bridges with a secured wireless sensor network.

DOT National Transportation Integrated Search

2011-12-01

"This collaborative research aims to develop a real-time stress monitoring system for highway bridges with a secured wireless sensor network. The near term goal is to collect wireless sensor data under different traffic patterns from local highway br...

Integration of bridge damage detection concepts and components : tech transfer summary.

DOT National Transportation Integrated Search

2013-10-01

Although bridge testing has been an important tool for evaluating structures for several decades, it has only been within the last decade that specific effort has been given to develop systems that are capable of operating in an autonomous fashion. T...

Load capacity of hollowed timber piles.

DOT National Transportation Integrated Search

1998-12-01

The goal of this study was to develop a reliable load-rating methodology for timber piles based on the level of documented damage. Louisiana currently has over 4,000 timber bridges in its inventory of over 13,800 bridges. A quarter of these 4,000 tim...

Community Garden: A Bridging Program between Formal and Informal Learning

ERIC Educational Resources Information Center

Datta, Ranjan

2016-01-01

Community garden activities can play a significant role in bridging formal and informal learning, particularly in urban children's science and environmental education. It promotes relational methods of learning, discussing, and practicing that will integrate food security, social interactions, community development, environmental activism, and…

Development of a TL-3 deep beam tubular backup bridge rail : executive summary report.

DOT National Transportation Integrated Search

2010-12-01

Ohio Department of Transportation (ODOT)s Office of Structural Engineering has a need to evaluate and, if necessary, improve an existing bridge rail design with a simple retrofitting procedure to meet current or proposed crash testing standards. T...

Development of methods for improving levels 1 and 2 met/ocean parameter predictions

DOT National Transportation Integrated Search

2011-02-01

The prediction of storm surge and wave forces and moments on bridges requires knowledge of design (100-year) water levels and wave heights and periods (met/ocean conditions) as well as bridge dimensions, elevation, orientation, etc. The American Asso...

An expert system as applied to bridges : software development phase.

DOT National Transportation Integrated Search

1989-01-01

This report describes the results of the third of a four-part study dealing with the use of a computerized expert system to assist bridge engineers in their structures management program. In this phase of the study, software (called DOBES) was writte...

Effects of realistic heat straightening repair on the properties and serviceability of damaged steel beam bridges.

DOT National Transportation Integrated Search

2012-02-01

The permanent deformations in steel beam bridges caused by collision with high profile vehicles can be repaired by heat straightening, : which is a structurally efficient and costeffective repair process developed by many engineers over the years....

Preventing Pollution to Local Waters, Bay; Preserving Historic Natural Bridge in Virginia

EPA Pesticide Factsheets

In helping to preserve one of the oldest tourist destinations in the country – a spectacular natural land bridge in Virginia – EPA funding is protecting the surrounding land from development that would have impacted local waters and the Chesapeake Bay.

Field demonstration of new bridge approach slab designs and performance : [tech summary].

DOT National Transportation Integrated Search

2014-06-01

The Louisiana Department of Transportation and Development (DOTD) has launched a major e ort to solve : the bridge bump problem by changing the design of approach slabs where di erential settlement is expected. : The objective is to nd a fe...

Campaign monitoring of railroad bridges in high-speed rail shared corridors using wireless smart sensors.

DOT National Transportation Integrated Search

2015-06-01

This research project used wireless smart sensors to develop a cost-effective and practical portable structural health monitoring : system for railroad bridges in North America. The system is designed for periodic deployment rather than as a permanen...

A BRIDGE partnership model for health management education in the Slovak Republic.

PubMed

West, D J; Krcmery, V; Rusnakova, V; Murgas, M

1998-01-01

An innovative Health Management Education Partnership (HMEP) was initiated to develop management education initiatives through the exchange of information and ideas. Health education efforts, projects and activities exist between the University of Scranton and three strategic partners in the Slovak Republic: Trnava University, the Health Management School and the University of Matej Bel. The BRIDGE model (Building Relationships in Developing and Growing Economies) utilizes several innovative educational initiatives and strategic projects including a professional journal, faculty development, professional development, curriculum development, certification and accreditation, faculty-students exchange and development of educational materials and modules. The BRIDGE organizational structure is reviewed as well as specific workplan objectives to operationalize the HMEP encouraging mutual cooperation, collaboration and sustainability of efforts. The model stresses implementation, monitoring, and evaluation of all initiatives through a strong community effort, focus on research, deployment of educational resources, curriculum modification, development of interpartnership activities, conferences, workshops, fieldwork experiences and study tours. Applied management practices enhance market-oriented solutions to health care delivery problems emphasizing a focus on privatization and entrepreneurship through education.

Integrating Gender and Group Differences into Bridging Strategy

NASA Astrophysics Data System (ADS)

Yılmaz, Serkan; Eryılmaz, Ali

2010-08-01

The main goal of this study was to integrate gender and group effect into bridging strategy in order to assess the effect of bridging analogy-based instruction on sophomore students' misconceptions in Newton's Third Law. Specifically, the authors developed and benefited from anchoring analogy diagnostic test to merge the effect of group and gender into the strategy. Newton's third law misconception test, attitude scale toward Newton's third law, and classroom observation checklists were the other measuring tools utilized throughout this quasi-experimental study. The researchers also developed or used several teaching/learning materials such as gender and group splitted concept diagrams, lesson plans, gender splitted frequency tables, make sense scales, PowerPoint slides, flash cards, and demonstrations. The convenience sample of the study chosen from the accessible population involved 308 students from two public universities. The results of multivariate analysis of covariance indicated that the bridging strategy had a significant effect on students' misconceptions in Newton's third law whereas it had no significant effect on students' attitudes toward Newton's third law.

Development of NASA-DeBakey Ventricular Assist Device Using Numerical Aerospace Simulation Technology

NASA Technical Reports Server (NTRS)

Kwak, Dochan

2000-01-01

Over three million Americans and 20 million people worldwide suffer from some form of heart failure. Mechanical heart assist devices are being used as a temporary support to sick ventricle and valves as a bridge-to-transplant or bridge-to-recovery. This viewgraph presentation gives an overview of the development of NASA-DeBakey Ventricular Assist Device (VAD) using numerical aerospace simulation technology.

Initial bridges between two ribosomal subunits are formed within 9.4 milliseconds, as studied by time-resolved cryo-EM.

PubMed

Shaikh, Tanvir R; Yassin, Aymen S; Lu, Zonghuan; Barnard, David; Meng, Xing; Lu, Toh-Ming; Wagenknecht, Terence; Agrawal, Rajendra K

2014-07-08

Association of the two ribosomal subunits during the process of translation initiation is a crucial step of protein synthesis. The two subunits (30S and 50S) of the bacterial 70S ribosome are held together by 12 dynamic bridges involving RNA-RNA, RNA-protein, and protein-protein interactions. The process of bridge formation, such as whether all these bridges are formed simultaneously or in a sequential order, is poorly understood. To understand such processes, we have developed and implemented a class of microfluidic devices that mix two components to completion within 0.4 ms and spray the mixture in the form of microdroplets onto an electron microscopy grid, yielding a minimum reaction time of 9.4 ms before cryofixation. Using these devices, we have obtained cryo-EM data corresponding to reaction times of 9.4 and 43 ms and have determined 3D structures of ribosomal subunit association intermediates. Molecular analyses of the cryo-EM maps reveal that eight intersubunit bridges (bridges B1a, B1b, B2a, B2b, B3, B7a, B7b, and B8) form within 9.4 ms, whereas the remaining four bridges (bridges B2c, B4, B5, and B6) take longer than 43 ms to form, suggesting that bridges are formed in a stepwise fashion. Our approach can be used to characterize sequences of various dynamic functional events on complex macromolecular assemblies such as ribosomes.

Verification of image orthorectification techniques for low-cost geometric inspection of masonry arch bridges

NASA Astrophysics Data System (ADS)

González-Jorge, Higinio; Riveiro, Belén; Varela, María; Arias, Pedro

2012-07-01

A low-cost image orthorectification tool based on the utilization of compact cameras and scale bars is developed to obtain the main geometric parameters of masonry bridges for inventory and routine inspection purposes. The technique is validated in three different bridges by comparison with laser scanning data. The surveying process is very delicate and must make a balance between working distance and angle. Three different cameras are used in the study to establish the relationship between the error and the camera model. Results depict nondependence in error between the length of the bridge element, the type of bridge, and the type of element. Error values for all the cameras are below 4 percent (95 percent of the data). A compact Canon camera, the model with the best technical specifications, shows an error level ranging from 0.5 to 1.5 percent.

Solutions of burnt-bridge models for molecular motor transport.

PubMed

Morozov, Alexander Yu; Pronina, Ekaterina; Kolomeisky, Anatoly B; Artyomov, Maxim N

2007-03-01

Transport of molecular motors, stimulated by interactions with specific links between consecutive binding sites (called "bridges"), is investigated theoretically by analyzing discrete-state stochastic "burnt-bridge" models. When an unbiased diffusing particle crosses the bridge, the link can be destroyed ("burned") with a probability p , creating a biased directed motion for the particle. It is shown that for probability of burning p=1 the system can be mapped into a one-dimensional single-particle hopping model along the periodic infinite lattice that allows one to calculate exactly all dynamic properties. For the general case of p<1 a theoretical method is developed and dynamic properties are computed explicitly. Discrete-time and continuous-time dynamics for periodic distribution of bridges and different burning dynamics are analyzed and compared. Analytical predictions are supported by extensive Monte Carlo computer simulations. Theoretical results are applied for analysis of the experiments on collagenase motor proteins.

RECENT PROGRESS OF CRACK BRIDGING MODELING OF DUCTILE-PHASE-TOUGHENED W-CU COMPOSITES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Setyawan, Wahyu; Henager, Charles H.; Wagner, Karla B.

2015-04-16

A crack bridging model using calculated Cu stress-strain curves has been developed to study the toughening of W-Cu composites. A strengthening factor and necking parameters have been added to the model for the ductile-phase bridges to incorporate constraint effects at small bridge sizes. Parametric studies are performed to investigate the effect of these parameters. The calculated maximum applied stress intensity, aKmax, to induce a 1-mm stable crack is compared to the experimental stress intensity at peak load, Kpeak. Without bridge necking, increasing the strengthening factor improves the agreement between aKmax and Kpeak when plotted vs. logarithm of the displacement rate.more » Improvement can also be achieved by allowing necking with a larger failure strain. While the slope is better matched with this latter approach, the calculated value of aKmax is significantly larger than Kpeak.« less

Thermal Bridge Effect of Aerated Concrete Block Wall in Cold Regions

NASA Astrophysics Data System (ADS)

Li, Baochang; Guo, Lirong; Li, Yubao; Zhang, Tiantian; Tan, Yufei

2018-01-01

As a self-insulating building material which can meet the 65 percent energy-efficiency requirements in cold region of China, aerated concrete blocks often go moldy, frost heaving, or cause plaster layer hollowing at thermal bridge parts in the extremely cold regions due to the restrictions of environmental climate and construction technique. L-shaped part and T-shaped part of aerated concrete walls are the most easily influenced parts by thermal bridge effect. In this paper, a field test is performed to investigate the scope of the thermal bridge effect. Moreover, a heat transfer calculation model for L-shaped wall and T-shaped wall is developed. According to the simulation results, the temperature fields of the thermal bridge affected regions are simulated and analyzed. The research outputs can provide theoretical basis for the application of aerated concrete wall in extremely cold regions.

Partial Insulation of Aerated Concrete Wall in its Thermal Bridge Regions

NASA Astrophysics Data System (ADS)

Li, Baochang; Guo, Lirong; Li, Yubao; Zhang, Tiantian; Tan, Yufei

2018-01-01

As a self-insulating building material which can meet the 65 percent energy-efficiency requirements in cold region of China, aerated concrete blocks often go moldy, frost heaving, or cause plaster layer hollowing at thermal bridge parts in the extremely cold regions due to the restrictions of environmental climate and construction technique. In this paper, partial insulation measures of the thermal-bridge position of these parts of aerated concrete walls are designed to weaken or even eliminate thermal bridge effect and improve the temperature of thermal-bridge position. A heat transfer calculation model for L-shaped wall and T-shaped wall is developed. Based on the simulation result, the influence of the thickness on the temperature field is analyzed. Consequently, the condensation inside self-thermal-insulating wall and frost heaving caused by condensation and low temperature will be reduced, avoiding damage to the wall body from condensation..

Exact Solutions of Burnt-Bridge Models for Molecular Motor Transport

NASA Astrophysics Data System (ADS)

Morozov, Alexander; Pronina, Ekaterina; Kolomeisky, Anatoly; Artyomov, Maxim

2007-03-01

Transport of molecular motors, stimulated by interactions with specific links between consecutive binding sites (called ``bridges''), is investigated theoretically by analyzing discrete-state stochastic ``burnt-bridge'' models. When an unbiased diffusing particle crosses the bridge, the link can be destroyed (``burned'') with a probability p, creating a biased directed motion for the particle. It is shown that for probability of burning p=1 the system can be mapped into one-dimensional single-particle hopping model along the periodic infinite lattice that allows one to calculate exactly all dynamic properties. For general case of p<1 a new theoretical method is developed, and dynamic properties are computed explicitly. Discrete-time and continuous-time dynamics, periodic and random distribution of bridges and different burning dynamics are analyzed and compared. Theoretical predictions are supported by extensive Monte Carlo computer simulations. Theoretical results are applied for analysis of the experiments on collagenase motor proteins.

Bridge Scour Measurements Using the Rfid Technology

NASA Astrophysics Data System (ADS)

Moustakidis, I.; Tsakiris, A. G.; Papanicolaou, T.

2010-12-01

The main purpose of this project is to develop a system for continuous monitoring scour around bridge piers and abutments (i.e. bridge scour) using the Radio Frequency IDentification (RFID) technology and examine its applicability for estimating scour around a pier or an existing bridge. Excessive bridge scour can compromise the bridge foundations and lead to dramatic bridge collapses with significant impacts on economy and traveling public safety. An RFID system consists of three main components: the low frequency reader (~134.2 kHz frequency), the transponder (derived from transmitter/responder) and the antenna (of rectangular shape with one or more loops). RFID is a technology that permits the wireless two-way transfer of information from a reader to a transponder via RF waves transmitted with an antenna. What makes RFIDs suitable for monitoring bridge scour is that no line of sight is necessary between the reader and the transponder, which can be detected even when it is buried in the bed substrate. The proposed system for monitoring bridge scour relies on the principle that transponders oriented perpendicular to antenna plane can be detected at longer distances, than transponders oriented parallel to it. We intend to attach transponders at predetermined locations (depths) along a chain with known length. The chain will subsequently be driven into the bed substrate at the location where bridge scour hole is expected within the detection range of the antenna, which will be installed directly above the chain. The chain will retain the transponders perpendicular to the antenna plane, so that they can be continuously detected. Once scour takes place, the transponders will be oriented parallel to the antenna plane and thus they will not be detected. The latter will indicate that bridge scour reached the known depth, at which the transponder was initially buried. Once a prototype RFID system is functional, future research will aim at combining it with satellite technology for real time acquisition of bridge scour information to a base station.

Element level bridge inspection : benefits and use of data for bridge management.

DOT National Transportation Integrated Search

2016-02-01

In 2012, Congress passed the Moving Ahead for Progress in the 21st Century Act (MAP-21) and committed to the development of a datadriven, : risk based approach to asset management in the United States. This law requires the collection and submission ...

Design and evaluation of steel bridges with double composite action

DOT National Transportation Integrated Search

2010-02-01

This report presents findings from a cooperative USF/URS/FDOT research study undertaken to develop design rules for : double composite steel bridges. In the study, a 48 ft long, 16 ft wide, 4 ft. 10 in. deep trapezoidal HPS 70W box section : desig...

Efficient load rating and quantification of life-cycle damage of Indiana bridges due to overweight loads.

DOT National Transportation Integrated Search

2016-02-01

In this study, a computational approach for conducting durability analysis of bridges using detailed finite element models is developed. The underlying approach adopted is based on the hypothesis that the two main factors affecting the life of a brid...

Next-generation wireless bridge weigh-in-motion (WIM) system integrated with nondestructive evaluation (NDE) capability for transportation infrastructure safety.

DOT National Transportation Integrated Search

2014-05-01

This project seeks to develop a rapidly deployable, low-cost, and wireless system for bridge : weigh-in-motion (BWIM) and nondestructive evaluation (NDE). The system is proposed to : assist in monitoring transportation infrastructure safety, for the ...

The Bridges Program.

ERIC Educational Resources Information Center

Bohnen, Elizabeth; Klie, Judy

This report describes BRIDGES, an employment equity special measures training program developed by the City of Toronto (Ontario, Canada). It was designed to help women employees move from their traditional jobs into trades, technical or operation (TTO) jobs within their own organization. The program is a combination of classroom sessions, shop…

The Simulation of Vibrations of Railway Beam Bridges in the Object-oriented Environment Delphi

NASA Astrophysics Data System (ADS)

Raspopov, Alexander; Artyomov, Vitaly; Rusu, Sergey

2010-01-01

The peculiarities of combination of finite-element method and equations of solid dynamics, the basic stages of development of the program complex Belinda for calculation of statics and dynamics of the rods constructions as applied to railway bridges are described.

Development and evaluation of an adhesively bonded panel-to-panel joint for a fiber-reinforced polymer bridge deck system.

DOT National Transportation Integrated Search

2007-01-01

A fiber-reinforced polymer (FRP) composite cellular deck system was used to rehabilitate a historical cast iron thru-truss structure (Hawthorne Street Bridge in Covington, Virginia). The most important characteristic of this application is reduction ...

Pilot project - demonstration of capabilities and benefits of bridge load rating through physical testing : tech transfer summary.

DOT National Transportation Integrated Search

2013-08-01

This project demonstrated the capabilities for load testing bridges in Iowa, developed and presented a webinar to local and state engineers, and produced a spreadsheet and benefit evaluation matrix that others can use to preliminarily assess where br...

Pier scour equations used in the People's Republic of China : review and summary

DOT National Transportation Integrated Search

1993-09-01

Equations for estimating scour depth at bridge structures was developed from model and field data presented at the Symposium on Scour at Bridges in China, 1964. These equations have been used in highway and railway engineering in China for more than ...

Journaling: A Bridge between School and Home

ERIC Educational Resources Information Center

McGough, Julie

2013-01-01

This article describes how first-grade students create meaningful communication with families and help build the student-teacher-parent relationship through journaling. Journals are a useful tool to bridge school and home. A journal can communicate learning goals, develop scientific vocabulary, and create dialogue through oral and written…

The introduction of modern timber bridges in Virginia : a final report on the Virginia timber bridge initiative.

DOT National Transportation Integrated Search

2002-01-01

In 1990, the Virginia General Assembly established a commission to propose and enhance the economic development of the Southside region of the Commonwealth, the tier of largely rural counties across the southern border. The commission's 1991 report, ...

Development of recommended resistance factors for drilled shafts in weak rocks based on o-cell tests : [technical summary].

DOT National Transportation Integrated Search

2010-03-01

Since October 1st 2007, federal-funded projects including new bridges have been mandated to be designed to meet American Association of State Highway and Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) Bridge Design Specifi...

Safety factor increase to fatigue limit states through shear spiking for timber railroad bridge rehabilitation - phase I.

DOT National Transportation Integrated Search

2014-11-01

The overall project is to demonstrate the effectiveness of shear spiking (technique alrea : dy developed : through a previous project). Many timber railroad bridges are deficient but i : t is too costly to replace them; : hence : , : inexpensive repa...

SMART PEBBLES : passive embeddable wireless sensors for chloride ingress monitoring in bridge decks.

DOT National Transportation Integrated Search

2003-06-01

SRI International has developed a wireless sensor for monitoring the level of chloride : ingress into concrete bridge decks. We call this device a Smart Pebble since it has : roughly the size and weight of a typical piece of the rock aggregate tha...

A new solution of measuring thermal response of prestressed concrete bridge girders for structural health monitoring

NASA Astrophysics Data System (ADS)

Jiao, Pengcheng; Borchani, Wassim; Hasni, Hassene; Lajnef, Nizar

2017-08-01

This study develops a novel buckling-based mechanism to measure the thermal response of prestressed concrete bridge girders under continuous temperature changes for structural health monitoring. The measuring device consists of a bilaterally constrained beam and a piezoelectric polyvinylidene fluoride transducer that is attached to the beam. Under thermally induced displacement, the slender beam is buckled. The post-buckling events are deployed to convert the low-rate and low-frequency excitations into localized high-rate motions and, therefore, the attached piezoelectric transducer is triggered to generate electrical signals. Attaching the measuring device to concrete bridge girders, the electrical signals are used to detect the thermal response of concrete bridges. Finite element simulations are conducted to obtain the displacement of prestressed concrete girders under thermal loads. Using the thermal-induced displacement as input, experiments are carried out on a 3D printed measuring device to investigate the buckling response and corresponding electrical signals. A theoretical model is developed based on the nonlinear Euler-Bernoulli beam theory and large deformation assumptions to predict the buckling mode transitions of the beam. Based on the presented theoretical model, the geometry properties of the measuring device can be designed such that its buckling response is effectively controlled. Consequently, the thermally induced displacement can be designed as limit states to detect excessive thermal loads on concrete bridge girders. The proposed solution sufficiently measures the thermal response of concrete bridges.

Bridging history and social psychology: what, how and why.

PubMed

Glăveanu, Vlad; Yamamoto, Koji

2012-12-01

This special issue aims to bridge history and social psychology by bringing together historians and social psychologists in an exercise of reading and learning from each other's work. This interdisciplinary exercise is not only timely but of great importance for both disciplines. Social psychologists can benefit from engaging with historical sources by being able to contextualise their findings and enrich their theoretical models. It is not only that all social and psychological phenomena have a history but this history is very much part of present-day and future developments. On the other hand historians can enhance their analysis of historical sources by drawing upon the conceptual tools developed in social psychology. They can "test" these tools and contribute to their validation and enrichment from completely different perspectives. Most important, as contributions to this special issue amply demonstrate, psychology's "historical turn" has the potential to shed a new light on striking, yet underexplored, similarities between contemporary public spheres and their pre-modern counterparts. This issue thereby calls into question the dichotomy between traditional and de-traditionalized societies-a distinction that lies at the heart of many social psychology accounts of the world we live in. The present editorial will introduce and consider this act of bridging history and social psychology by focusing on three main questions: What is the bridge made of? How can the two disciplines be bridged? and Why we cross this interdisciplinary bridge? In the end a reflection on the future of this collaboration will be offered.

Determination of the Bridging Ligand in the Active Site of Tyrosinase.

PubMed

Zou, Congming; Huang, Wei; Zhao, Gaokun; Wan, Xiao; Hu, Xiaodong; Jin, Yan; Li, Junying; Liu, Junjun

2017-10-28

Tyrosinase is a type-3 copper enzyme that is widely distributed in plants, fungi, insects, and mammals. Developing high potent inhibitors against tyrosinase is of great interest in diverse fields including tobacco curing, food processing, bio-insecticides development, cosmetic development, and human healthcare-related research. In the crystal structure of Agaricus bisporus mushroom tyrosinase, there is an oxygen atom bridging the two copper ions in the active site. It is unclear whether the identity of this bridging oxygen is a water molecule or a hydroxide anion. In the present study, we theoretically determine the identity of this critical bridging oxygen by performing first-principles hybrid quantum mechanics/molecular mechanics/Poisson-Boltzmann-surface area (QM/MM-PBSA) calculations along with a thermodynamic cycle that aim to improve the accuracy. Our results show that the binding with water molecule is energy favored and the QM/MM-optimized structure is very close to the crystal structure, whereas the binding with hydroxide anions causes the increase of energy and significant structural changes of the active site, indicating that the identity of the bridging oxygen must be a water molecule rather than a hydroxide anion. The different binding behavior between water and hydroxide anions may explain why molecules with a carboxyl group or too many negative charges have lower inhibitory activity. In light of this, the design of high potent active inhibitors against tyrosinase should satisfy both the affinity to the copper ions and the charge neutrality of the entire molecule.

Error Sources in Proccessing LIDAR Based Bridge Inspection

NASA Astrophysics Data System (ADS)

Bian, H.; Chen, S. E.; Liu, W.

2017-09-01

Bridge inspection is a critical task in infrastructure management and is facing unprecedented challenges after a series of bridge failures. The prevailing visual inspection was insufficient in providing reliable and quantitative bridge information although a systematic quality management framework was built to ensure visual bridge inspection data quality to minimize errors during the inspection process. The LiDAR based remote sensing is recommended as an effective tool in overcoming some of the disadvantages of visual inspection. In order to evaluate the potential of applying this technology in bridge inspection, some of the error sources in LiDAR based bridge inspection are analysed. The scanning angle variance in field data collection and the different algorithm design in scanning data processing are the found factors that will introduce errors into inspection results. Besides studying the errors sources, advanced considerations should be placed on improving the inspection data quality, and statistical analysis might be employed to evaluate inspection operation process that contains a series of uncertain factors in the future. Overall, the development of a reliable bridge inspection system requires not only the improvement of data processing algorithms, but also systematic considerations to mitigate possible errors in the entire inspection workflow. If LiDAR or some other technology can be accepted as a supplement for visual inspection, the current quality management framework will be modified or redesigned, and this would be as urgent as the refine of inspection techniques.

Cranial dural arteriovenous shunts. Part 1. Anatomy and embryology of the bridging and emissary veins.

PubMed

Baltsavias, Gerasimos; Parthasarathi, Venkatraman; Aydin, Emre; Al Schameri, Rahman A; Roth, Peter; Valavanis, Anton

2015-04-01

We reviewed the anatomy and embryology of the bridging and emissary veins aiming to elucidate aspects related to the cranial dural arteriovenous fistulae. Data from relevant articles on the anatomy and embryology of the bridging and emissary veins were identified using one electronic database, supplemented by data from selected reference texts. Persisting fetal pial-arachnoidal veins correspond to the adult bridging veins. Relevant embryologic descriptions are based on the classic scheme of five divisions of the brain (telencephalon, diencephalon, mesencephalon, metencephalon, myelencephalon). Variation in their exact position and the number of bridging veins is the rule and certain locations, particularly that of the anterior cranial fossa and lower posterior cranial fossa are often neglected in prior descriptions. The distal segment of a bridging vein is part of the dural system and can be primarily involved in cranial dural arteriovenous lesions by constituting the actual site of the shunt. The veins in the lamina cribriformis exhibit a bridging-emissary vein pattern similar to the spinal configuration. The emissary veins connect the dural venous system with the extracranial venous system and are often involved in dural arteriovenous lesions. Cranial dural shunts may develop in three distinct areas of the cranial venous system: the dural sinuses and their interfaces with bridging veins and emissary veins. The exact site of the lesion may dictate the arterial feeders and original venous drainage pattern.

Bridge-Scour Data Management System user's manual

USGS Publications Warehouse

Landers, Mark N.; Mueller, David S.; Martin, Gary R.

1996-01-01

The Bridge-Scour Data Management System (BSDMS) supports preparation, compilation, and analysis of bridge-scour data. The BSDMS provides interactive storage, retrieval, selection, editing, and display of bridge-scour data sets. Bridge-scour data sets include more than 200 site and measurement attributes of the channel geometry, flow hydraulics, hydrology, sediment, geomorphic-setting, location, and bridge specifications. This user's manual provides a general overview of the structure and organization of BSDMS data sets and detailed instructions to operate the program. Attributes stored by the BSDMS are described along with an illustration of the input screen where the attribute can be entered or edited. Measured scour depths can be compared with scour depths predicted by selected published equations using the BSDMS. The selected published equations available in the computational portion of the BSDMS are described. This manual is written for BSDMS, version 2.0. The data base will facilitate: (1) developing improved estimators of scour for specific regions or conditions; (2) describing scour processes; and (3) reducing risk from scour at bridges. BSDMS is available in DOS and UNIX versions. The program was written to be portable and, therefore, can be used on multiple computer platforms. Installation procedures depend on the computer platform, and specific installation instructions are distributed with the software. Sample data files and data sets of 384 pier-scour measurements from 56 bridges in 14 States are also distributed with the software.

Long-Term Structural Health Monitoring System for a High-Speed Railway Bridge Structure

PubMed Central

Wu, Lai-Yi

2015-01-01

Nanjing Dashengguan Bridge, which serves as the shared corridor crossing Yangtze River for both Beijing-Shanghai high-speed railway and Shanghai-Wuhan-Chengdu railway, is the first 6-track high-speed railway bridge with the longest span throughout the world. In order to ensure safety and detect the performance deterioration during the long-time service of the bridge, a Structural Health Monitoring (SHM) system has been implemented on this bridge by the application of modern techniques in sensing, testing, computing, and network communication. The SHM system includes various sensors as well as corresponding data acquisition and transmission equipment for automatic data collection. Furthermore, an evaluation system of structural safety has been developed for the real-time condition assessment of this bridge. The mathematical correlation models describing the overall structural behavior of the bridge can be obtained with the support of the health monitoring system, which includes cross-correlation models for accelerations, correlation models between temperature and static strains of steel truss arch, and correlation models between temperature and longitudinal displacements of piers. Some evaluation results using the mean value control chart based on mathematical correlation models are presented in this paper to show the effectiveness of this SHM system in detecting the bridge's abnormal behaviors under the varying environmental conditions such as high-speed trains and environmental temperature. PMID:26451387

Nondestructive Evaluation of Concrete Bridge Decks with Automated Acoustic Scanning System and Ground Penetrating Radar.

PubMed

Sun, Hongbin; Pashoutani, Sepehr; Zhu, Jinying

2018-06-16

Delamanintions and reinforcement corrosion are two common problems in concrete bridge decks. No single nondestructive testing method (NDT) is able to provide comprehensive characterization of these defects. In this work, two NDT methods, acoustic scanning and Ground Penetrating Radar (GPR), were used to image a straight concrete bridge deck and a curved intersection ramp bridge. An acoustic scanning system has been developed for rapid delamination mapping. The system consists of metal-ball excitation sources, air-coupled sensors, and a GPS positioning system. The acoustic scanning results are presented as a two-dimensional image that is based on the energy map in the frequency range of 0.5⁻5 kHz. The GPR scanning results are expressed as the GPR signal attenuation map to characterize concrete deterioration and reinforcement corrosion. Signal processing algorithms for both methods are discussed. Delamination maps from the acoustic scanning are compared with deterioration maps from the GPR scanning on both bridges. The results demonstrate that combining the acoustic and GPR scanning results will provide a complementary and comprehensive evaluation of concrete bridge decks.

Laboratory and field performance of FOS sensors in static and dynamic strain monitoring in concrete bridge decks

NASA Astrophysics Data System (ADS)

Benmokrane, B.; Debaiky, A.; El-Ragaby, A.; Roy, R.; El-Gamal, S.; El-Salakawy, E.

2006-03-01

There is a growing need for designing and constructing innovative concrete bridges using FRP reinforcing bars as internal reinforcement to avoid the corrosion problems and high costs of maintenance and repair. For efficient use and to increase the lifetime of these bridges, it is important to develop efficient monitoring systems for such innovative structures. Fabry-Perot and Bragg fibre optic sensors (FOS) that can measure the strains and temperature are promising candidates for life-long health monitoring of these structures. This article reports laboratory and field performance of Fabry-Perot and Bragg FOS sensors as well as electrical strain gauges in static and dynamic strain monitoring in concrete bridge decks. The laboratory tests include tensile testing of glass FRP bars and testing of full-scale concrete bridge deck slabs reinforced with glass and carbon FRP bars under static and cyclic concentrated loads. The field tests include static and dynamic testing of two bridges reinforced with steel and glass FRP bars. The obtained strain results showed satisfactory agreement between the different gauges.

Fatigue assessment of an existing steel bridge by finite element modelling and field measurements

NASA Astrophysics Data System (ADS)

Kwad, J.; Alencar, G.; Correia, J.; Jesus, A.; Calçada, R.; Kripakaran, P.

2017-05-01

The evaluation of fatigue life of structural details in metallic bridges is a major challenge for bridge engineers. A reliable and cost-effective approach is essential to ensure appropriate maintenance and management of these structures. Typically, local stresses predicted by a finite element model of the bridge are employed to assess the fatigue life of fatigue-prone details. This paper illustrates an approach for fatigue assessment based on measured data for a connection in an old bascule steel bridge located in Exeter (UK). A finite element model is first developed from the design information. The finite element model of the bridge is calibrated using measured responses from an ambient vibration test. The stress time histories are calculated through dynamic analysis of the updated finite element model. Stress cycles are computed through the rainflow counting algorithm, and the fatigue prone details are evaluated using the standard SN curves approach and the Miner’s rule. Results show that the proposed approach can estimate the fatigue damage of a fatigue prone detail in a structure using measured strain data.

Seismic fragility curves of bridge piers accounting for ground motions in Korea

NASA Astrophysics Data System (ADS)

Nguyen, Duy-Duan; Lee, Tae-Hyung

2018-04-01

Korea is located in a slight-to-moderate seismic zone. Nevertheless, several studies pointed that the peak earthquake magnitude in the region can be reached to approximately 6.5. Accordingly, a seismic vulnerability evaluation of the existing structures accounting for ground motions in Korea is momentous. The purpose of this paper is to develop seismic fragility curves for bridge piers of a steel box girder bridge equipped with and without base isolators based on a set of ground motions recorded in Korea. A finite element simulation platform, OpenSees, is utilized to perform nonlinear time history analyses of the bridges. A series of damage states is defined based on a damage index which is expressed in terms of the column displacement ductility ratio. The fragility curves based on Korean motions were thereafter compared with the fragility curves generated using worldwide earthquakes to assess the effect of the two ground motion groups on the seismic fragility curves of the bridge piers. The results reveal that both non- and base-isolated bridge piers are less vulnerable during the Korean ground motions than that under worldwide earthquakes.

Pegasus power system facility upgrades

NASA Astrophysics Data System (ADS)

Lewicki, B. T.; Kujak-Ford, B. A.; Winz, G. R.

2008-11-01

Two key Pegasus systems have been recently upgraded: the Ohmic-transformer IGCT bridge control system, and the plasma-gun injector power system. The Ohmic control system contains two new microprocessor controlled components to provide an interface between the PWM controller and the IGCT bridges. An interface board conditions the command signals from the PWM controller. A splitter/combiner board routes the conditioned PWM commands to an array of IGCT bridges and interprets IGCT bridge status. This system allows for any PWM controller to safely control IGCT bridges. Future developments will include a transition to a polyphasic bridge control. This will allow for 3 to 4 times the present pulse length and provide a much higher switching frequency. The plasma gun injector system now includes active current feedback control on gun bias current via PWM buck type power supplies. Near term goals include a doubling or tripling of the applied bias voltage. Future arc bias system power supplies may include a simpler boost type system which will allow access to even higher voltages using existing low voltage energy storage systems.

Hydraulic survey and scour assessment of Bridge 524, Tanana River at Big Delta, Alaska

USGS Publications Warehouse

Heinrichs, Thomas A.; Langley, Dustin E.; Burrows, Robert L.; Conaway, Jeffrey S.

2007-01-01

Bathymetric and hydraulic data were collected August 26–28, 1996, on the Tanana River at Big Delta, Alaska, at the Richardson Highway bridge and Trans-Alaska Pipeline crossing. Erosion along the right (north) bank of the river between the bridge and the pipeline crossing prompted the data collection. A water-surface profile hydraulic model for the 100- and 500-year recurrence-interval floods was developed using surveyed information. The Delta River enters the Tanana immediately downstream of the highway bridge, causing backwater that extends upstream of the bridge. Four scenarios were considered to simulate the influence of the backwater on flow through the bridge. Contraction and pier scour were computed from model results. Computed values of pier scour were large, but the scour during a flood may actually be less because of mitigating factors. No bank erosion was observed at the time of the survey, a low-flow period. Erosion is likely to occur during intermediate or high flows, but the actual erosion processes are unknown at this time.

Alabama Bridges: A Comprehensive Model for a Program of Care and Supervision of Older Children and Young Adolescents in Out-of-School Time. Program Manual.

ERIC Educational Resources Information Center

Bowles, Laura; Piggott, Gail B.

The Employers' Child Care Alliance, a group of major employers in Lee County, Alabama, developed the "Bridges" program, an innovative program for children ages 10-14 during out-of-school time. The program focuses on the growth of the whole child, specifically in areas not traditionally focused on in school, such as creative development, cultural…

Bridging the Gap: Linking Simulation and Testing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Krajewski, Paul E.; Carsley, John; Stoudt, Mark R.

2012-09-01

The Materials Genome Initiative (MGI) which is a key enabler for the Advanced Manufacturing Partnership, announced in 2011 by U.S. President Barack Obama, was established to accelerate the development and deployment of advanced materials. The MGI is driven by the need to "bridge the gap" between (I) experimental results and computational analysis to enable the rapid development and validation of new mateirals, and (II) the processes required to convert these materials into useable goods.

NDE of polymeric composite material bridge components

NASA Astrophysics Data System (ADS)

Duke, John C., Jr.; Horne, Michael R.

1998-03-01

Rapid advancements with respect to utilization of polymeric composite materials for bridge components is occurring. This situation is driven primarily by the potential improvements offered by these materials with respect to long term durability. However, because of the developmental nature of these materials much of the materials characterization has involved short term testing without the synergistic effects of environmental exposure. Efforts to develop nondestructive evaluation procedures, essential for any wide spread use in critical structural applications, have been consequently limited. This paper discuses the effort to develop NDE methods for field inspection of hybrid glass and carbon fiber reinforced vinyl ester pultruded 'double box' I beams that are installed in a small bridge over Tom's Creek, in Blacksburg, Virginia. Integrated structural element sensors, dormant infrared devices, as well as acousto-ultrasonic methods are under development for detecting and monitoring the occurrence and progression of life limiting deterioration mechanisms.

Bridging Cultures and Traditions for Educational and International Development: Comparative Research, Dialogue and Difference

NASA Astrophysics Data System (ADS)

Crossley, Michael

2008-07-01

Addressing the central theme of the XIII World Congress, the paper explores a number of contemporary theoretical, methodological and organisational developments in the field of comparative education. In doing so it draws upon the author's recent work and a selection of studies carried out in the South Pacific, the Caribbean and Africa. It is argued that disciplined comparative and international research can contribute much to the development of theory and methodology - as well as to the improvement of policy and practice in education world-wide. For this to be realised it is maintained that ongoing efforts to challenge and `reconceptualise' the field deserve sustained support - and increased attention to a more effective `bridging of cultures and traditions'. This `bridging' thesis is examined in greater depth, pointing to possible ways forward for those engaged in advancing the future of comparative research in education and in the social sciences more generally.

Development of a digital solar simulator based on full-bridge converter

NASA Astrophysics Data System (ADS)

Liu, Chen; Feng, Jian; Liu, Zhilong; Tong, Weichao; Ji, Yibo

2014-02-01

With the development of solar photovoltaic, distribution schemes utilized in power grid had been commonly application, and photovoltaic (PV) inverter is an essential equipment in grid. In this paper, a digital solar simulator based on full-bridge structure is presented. The output characteristic curve of system is electrically similar to silicon solar cells, which can greatly simplify research methods of PV inverter, improve the efficiency of research and development. The proposed simulator consists on a main control board based on TM320F28335, phase-shifted zero-voltage-switching (ZVS) DC-DC full-bridge converter and voltage and current sampling circuit, that allows emulating the voltage-current curve with the open-circuit voltage (Voc) of 900V and the short-circuit current (Isc) of 18A .When the system connected to a PV inverter, the inverter can quickly track from the open-circuit to the maximum power point and keep stability.

Investigation of Thermocapillary Convection of High Prandtl Number Fluid Under Microgravity

NASA Technical Reports Server (NTRS)

Liang, Ruquan; Duan, Guangdong

2012-01-01

Thermocapillary convection in a liquid bridge, which is suspended between two coaxial disks under zero gravity, has been investigated numerically. The Navier-Stokes equations coupled with the energy conservation equation are solved on a staggered grid, and the level set approach is used to capture the free surface deformation of the liquid bridge. The velocity and temperature distributions inside the liquid bridge are analyzed. It is shown from this work that as the development of the thermocapillary convection, the center of the vortex inside the liquid bridge moves down and reaches an equilibrium position gradually. The temperature gradients in the regions near the upper center axis and the bottom cold corner are higher than those in the other regions.

Development of Vibration-Based Piezoelectric Raindrop Energy Harvesting System

NASA Astrophysics Data System (ADS)

Wong, Chin Hong; Dahari, Zuraini

2017-03-01

The trend of finding new means to harvest energy has triggered numerous researches to explore the potential of raindrop energy harvesting. This paper presents an investigation on raindrop energy harvesting which compares the performance of polyvinylidene fluoride (PVDF) cantilever and bridge structure transducers and the development of a raindrop energy harvesting system. The parameters which contribute to the output voltage such as droplet size, droplets released at specific heights and dimensions of PVDF transducers are analyzed. Based on the experimental results, the outcomes have shown that the bridge structure transducer generated a higher voltage than the cantilever. Several dimensions have been tested and it was found that the 30 mm × 4 mm × 25 μm bridge structure transducer generated a relatively high AC open-circuit voltage, which is 4.22 V. The power generated by the bridge transducer is 18 μW across a load of 330 kΩ. The transducer is able to drive up a standard alternative current (AC) to direct current (DC) converter (full-wave bridge rectifier). It generated a DC voltage, V DC of 8.7 mV and 229 pW across a 330 kΩ resistor per drop. It is also capable to generate 9.3 nJ in 20 s from an actual rain event.

Dynamic characterization and damage detection in the I-40 bridge over the Rio Grande

DOE Office of Scientific and Technical Information (OSTI.GOV)

Farrar, C.R.; Baker, W.E.; Bell, T.M.

In the 1960`s and 1970`s over 2500 bridges were built in the U.S. with a design similar to those on Interstate 40 over the Rio Grande in Albuquerque, New Mexico. These bridges were built without structural redundancy and typically have only two plate girders carrying the entire dead and live loads. Failure of either girder is assumed to produce catastrophic failure of the bridge, hence these bridges are referred to as fracture-critical bridges. The Federal Highway Administration (FHWA) and the National Science Foundation (NSF) have provided funds to New Mexico State University (NMSU) through the New Mexico State Highway andmore » Transportation Department (NMSH&TD) and The Alliance For Transportation Research (ATR) for evaluation and testing of the existing fracture critical bridges over the Rio Grande. Because the 1-40 bridges over the Rio Grande were to be razed during the summer of 1993, the investigators were able to introduce simulated fatigue cracks, similar to those observed in the field, into the structure in order to test various damage identification methods and to observe the changes in load paths through the structure caused by the cracking. To support this research effort, NMSU contracted Los Alamos National Laboratory (LANL) to perform experimental modal analyses, and to develop experimentally verified numerical models of the bridge. Scientists from the LANL`s Condensed Matter and Thermal Physics Group (P-10) applied state-of-the-art sensors and data acquisition software to the modal tests. Engineers from the LANL`s Advanced Engineering Technology Group (MEE-13) conducted ambient and forced vibration tests to verify detailed and simplified finite element models of the bridge. Forced vibration testing was done in conjunction with engineers from Sandia National Laboratory (SNL) who provided and operated a hydraulic shaker.« less

Bridge maintenance to enhance corrosion resistance and performance of steel girder bridges

NASA Astrophysics Data System (ADS)

Moran Yanez, Luis M.

The integrity and efficiency of any national highway system relies on the condition of the various components. Bridges are fundamental elements of a highway system, representing an important investment and a strategic link that facilitates the transport of persons and goods. The cost to rehabilitate or replace a highway bridge represents an important expenditure to the owner, who needs to evaluate the correct time to assume that cost. Among the several factors that affect the condition of steel highway bridges, corrosion is identified as the main problem. In the USA corrosion is the primary cause of structurally deficient steel bridges. The benefit of regular high-pressure superstructure washing and spot painting were evaluated as effective maintenance activities to reduce the corrosion process. The effectiveness of steel girder washing was assessed by developing models of corrosion deterioration of composite steel girders and analyzing steel coupons at the laboratory under atmospheric corrosion for two alternatives: when high-pressure washing was performed and when washing was not considered. The effectiveness of spot painting was assessed by analyzing the corrosion on steel coupons, with small damages, unprotected and protected by spot painting. A parametric analysis of corroded steel girder bridges was considered. The emphasis was focused on the parametric analyses of corroded steel girder bridges under two alternatives: (a) when steel bridge girder washing is performed according to a particular frequency, and (b) when no bridge washing is performed to the girders. The reduction of structural capacity was observed for both alternatives along the structure service life, estimated at 100 years. An economic analysis, using the Life-Cycle Cost Analysis method, demonstrated that it is more cost-effective to perform steel girder washing as a scheduled maintenance activity in contrast to the no washing alternative.

Direct numerical simulation of gas-solid-liquid flows with capillary effects: An application to liquid bridge forces between spherical particles.

PubMed

Sun, Xiaosong; Sakai, Mikio

2016-12-01

In this study, a numerical method is developed to perform the direct numerical simulation (DNS) of gas-solid-liquid flows involving capillary effects. The volume-of-fluid method employed to track the free surface and the immersed boundary method is adopted for the fluid-particle coupling in three-phase flows. This numerical method is able to fully resolve the hydrodynamic force and capillary force as well as the particle motions arising from complicated gas-solid-liquid interactions. We present its application to liquid bridges among spherical particles in this paper. By using the DNS method, we obtain the static bridge force as a function of the liquid volume, contact angle, and separation distance. The results from the DNS are compared with theoretical equations and other solutions to examine its validity and suitability for modeling capillary bridges. Particularly, the nontrivial liquid bridges formed in triangular and tetrahedral particle clusters are calculated and some preliminary results are reported. We also perform dynamic simulations of liquid bridge ruptures subject to axial stretching and particle motions driven by liquid bridge action, for which accurate predictions are obtained with respect to the critical rupture distance and the equilibrium particle position, respectively. As shown through the simulations, the strength of the present method is the ability to predict the liquid bridge problem under general conditions, from which models of liquid bridge actions may be constructed without limitations. Therefore, it is believed that this DNS method can be a useful tool to improve the understanding and modeling of liquid bridges formed in complex gas-solid-liquid flows.

Exploring the Science--Society Interface with a Bridging Research Course

ERIC Educational Resources Information Center

Boltax, Ariana L.; Kosinski-Collins, Melissa S.; Pontrello, Jason K.

2016-01-01

This article describes the development of a model for an optional, research-based course that bridges two existing, traditionally separate, introductory science courses. This research course provided freedom for students to design and implement new experiments on the basis of technical foundations built from enrollment in separate introductory…

Development of a cost-effective concrete bridge deck preservation program : volume 2--final results and recommendations.

DOT National Transportation Integrated Search

2016-07-01

The deterioration of bridge decks has been identified as a major problem in Indiana. The primary cause of this deterioration is salt water : ingress from the application of deicing salts during the winter. Deicing chemicals placed on the road mix wit...

Capacitance discharge system for ignition of Single Bridge Apollo Standard Initiators (SBASI)

NASA Technical Reports Server (NTRS)

Ward, R. D.

1974-01-01

The design support data developed during the single bridge Apollo standard initiator (SBASI) program are presented. A circuit was designed and bread-board tested to verify operational capabilities of the circuit. Test data, design criteria, weight, and reliability trade-off considerations, and final design recommendations are reported.

A Model to predict the impact of specification changes on the chloride-induced service life of Virginia bridge decks.

DOT National Transportation Integrated Search

2002-01-01

A model to determine the time to first repair and subsequent rehabilitation of concrete bridge decks exposed to chloride deicer salts that recognizes and incorporates the statistical nature of factors affecting the corrosion process is developed. The...

Tsunami design criteria for coastal infrastructure : a case study for Spencer Creek Bridge, Oregon.

DOT National Transportation Integrated Search

2006-11-01

The load effects on a coastal bridge due to the impact of a tsunami wave were developed. Three Cascadia Fault : rupture scenarios were considered using the Cornell model and the FVWAVE model to generate the waves for : each scenario. The FVWAVE model...

Investigation of pile setup (freeze) in Alabama : development of a setup prediction method and implementation into LRFD driven pile design.

DOT National Transportation Integrated Search

2015-06-01

The Alabama Department of Transportation (ALDOT) often uses deep foundations : consisting of driven piles, particularly in the southern half of the state, to support bridges or other : highway structures. In the fiscal year 2012, a total of 22 bridge...

Laser welded steel sandwich panel bridge deck development : finite element analysis and stake weld strength tests.

DOT National Transportation Integrated Search

2009-09-01

This report summarizes the analysis of laser welded steel sandwich panels for use in bridge structures and : static testing of laser stake welded lap shear coupons. Steel sandwich panels consist of two face sheets : connected by a relatively low-dens...

Development of an improved capability for predicting the response of highway bridges : final report.

DOT National Transportation Integrated Search

1986-01-01

This study compared experimental and analytical stress and deflection response of a simply-supported highway bridge as measured from a field test and as predicted from a finite-element analysis. The field test was conducted on one span of a six-span ...

Field monitoring of the I-295 bridge over the James River : instrumentation installation and construction period studies : interim report.

DOT National Transportation Integrated Search

1988-01-01

This report reviews the various techniques considered for instrumenting the Rte. 1-295 cable-stayed bridge over the James River near Richmond, Virginia. From this review an instrumentation plan is developed to meet the following objectives: 1. to det...

Neighborhood Bridges: 2012-2013 Evaluation Report

ERIC Educational Resources Information Center

Ingram, Debra

2013-01-01

Neighborhood Bridges is a nationally recognized literacy program using storytelling and creative drama to help children develop their critical literacy skills and to transform them into storytellers of their own lives. In 2012-2013, a total of 640 students in grades three through six from twenty-three classrooms in eleven schools across the…

Bridge 47--Building Global Citizenship

ERIC Educational Resources Information Center

Lappalainen, Rilli

2018-01-01

Preparing young people to solve the world's greatest challenges is necessary to achieve the Sustainable Development Goals, as recognized in Target 4.7 for global citizenship. The Bridge 47 Network brings together different perspectives and approaches in values-based education to provide a forum to examine the skills and competencies needed to be…

Focus on Student Success: Components for Effective Summer Bridge Programs

ERIC Educational Resources Information Center

Gonzalez Quiroz, Alicia; Garza, Nora R.

2018-01-01

Using research focused on best practices, focus group information, and data analytics, the Title V: Focus on Student Success (FOSS) Grant created a model for the development, implementation, and evaluation of a summer bridge program. Results included increased academic performance indicators in first-year Hispanic college students. Validation for…

Hydraulic risk assessment of bridges using UAV photogrammetry

NASA Astrophysics Data System (ADS)

Hackl, Jürgen; Adey, Bryan T.; Woźniak, Michał; Schümperlin, Oliver

2017-04-01

Road networks are essential for economic growth and development. Of the objects within a road network, bridges are of special interest, because their failure often results in relatively large interruptions to how the network is used, their replacement costs are generally large, and it usually takes a considerable amount of time to restore them once they have failed. Of the different types of bridges, bridges in mountainous regions are of special interest because their failure could cause severe societal consequences, for example, if it renders an area inaccessible. One of the main causes of the failure of bridges in mountainous regions is the occurrence of a hydraulic event, for example, flood waters above a certain level, scour below a certain depth or debris build up beyond a certain level. An assessment of risk related to a bridge in a mountainous region is challenging. The probability of occurrence of these events, and the resulting consequences, depend greatly on the characteristics (e.g. slope, soil, vegetation, precipitation, …) of the specific regions where the bridges are located. An indication of the effect of these characteristics can be seen in the sediment deposition during floods in mountain catchments. Additionally, there is often no, or no recent, topological information that can be used to develop terrain models to be used for realistic water flow simulations in mountain regions, and most hydrology and hydraulic models have been developed for lower gradient rivers and can often not be directly used to model water flow in mountain rivers. In an effort to improve the assessment of risk related to bridges in mountainous regions, using the setting for risk assessments established by Hackl et al. (2015) and Adey et al. (2016), an investigation was undertaken to determine whether unmanned aerial vehicles (UAVs) and photogrammetry could be used to generate the topological information required to run realistic water flow simulations. The process investigated includes: the use of geo-referenced images, taken by an UAV, the exportation of these images into a photogrammetric software, the creation of a 3D mesh of the terrain from these images, the conversion of the 3D mesh to a computational mesh, the use of the computational mesh to build a hydrodynamic model, and the use of the hydrodynamic model to run flow simulations. The process was used to estimate the complex water flow near a single span concrete bridge in the Canton of Grisons, Switzerland. The hydraulic events (abutment scour and overflow) predicted by the developed model were compared with with historical observations from a recent flood event in the region. The hydraulic events predicted by the developed model correspond with historical observations, indicating that the topological information collected in this way is sufficiently accurate to be used to simulate complex flow situations, which can be used in bridge risk assessments. Hackl, J., Adey, B.T., Heitzler, M., and Iosifescu Enescu, I. (2015). "An Overarching Risk Assessment Process to Evaluate the Risks Associated with Infrastructure Networks due to Natural Hazards." International Journal of Performability Engineering, 11(2), 153-168. Adey, B.T., Hackl, J., Lam, J.C., van Gelder, P., Prak, P., van Erp, N., Heitzler, M., Iosifescu Enescu, I., and Hurni, L. (2016). "Ensuring acceptable levels of infrastructure related risks due to natural hazards with emphasis on conducting stress tests." 1st International Symposium on Infrastructure Asset Management (SIAM2016), K. Kobayashi, ed., Kyoto, Japan, 19-29 (Jan).

A knowledge transfer scheme to bridge the gap between science and practice: an integration of existing research frameworks into a tool for practice.

PubMed

Verhagen, Evert; Voogt, Nelly; Bruinsma, Anja; Finch, Caroline F

2014-04-01

Evidence of effectiveness does not equal successful implementation. To progress the field, practical tools are needed to bridge the gap between research and practice and to truly unite effectiveness and implementation evidence. This paper describes the Knowledge Transfer Scheme integrating existing implementation research frameworks into a tool which has been developed specifically to bridge the gap between knowledge derived from research on the one side and evidence-based usable information and tools for practice on the other.

Nonlinear Cross-Bridge Elasticity and Post-Power-Stroke Events in Fast Skeletal Muscle Actomyosin

PubMed Central

Persson, Malin; Bengtsson, Elina; ten Siethoff, Lasse; Månsson, Alf

2013-01-01

Generation of force and movement by actomyosin cross-bridges is the molecular basis of muscle contraction, but generally accepted ideas about cross-bridge properties have recently been questioned. Of the utmost significance, evidence for nonlinear cross-bridge elasticity has been presented. We here investigate how this and other newly discovered or postulated phenomena would modify cross-bridge operation, with focus on post-power-stroke events. First, as an experimental basis, we present evidence for a hyperbolic [MgATP]-velocity relationship of heavy-meromyosin-propelled actin filaments in the in vitro motility assay using fast rabbit skeletal muscle myosin (28–29°C). As the hyperbolic [MgATP]-velocity relationship was not consistent with interhead cooperativity, we developed a cross-bridge model with independent myosin heads and strain-dependent interstate transition rates. The model, implemented with inclusion of MgATP-independent detachment from the rigor state, as suggested by previous single-molecule mechanics experiments, accounts well for the [MgATP]-velocity relationship if nonlinear cross-bridge elasticity is assumed, but not if linear cross-bridge elasticity is assumed. In addition, a better fit is obtained with load-independent than with load-dependent MgATP-induced detachment rate. We discuss our results in relation to previous data showing a nonhyperbolic [MgATP]-velocity relationship when actin filaments are propelled by myosin subfragment 1 or full-length myosin. We also consider the implications of our results for characterization of the cross-bridge elasticity in the filament lattice of muscle. PMID:24138863

Patterns of premature physeal arrest: MR imaging of 111 children.

PubMed

Ecklund, Kirsten; Jaramillo, Diego

2002-04-01

The purpose of this study was to use MR imaging, especially fat-suppressed three-dimensional (3D) spoiled gradient-recalled echo sequences, to identify patterns of growth arrest after physeal insult in children. We evaluated 111 children with physeal bone bridges (median age, 11.4 years) using MR imaging to analyze bridge size, location in physis, signal intensity, growth recovery lines, avascular necrosis, and metaphyseal cartilage tongues. Fifty-eight patients underwent fat-suppressed 3D spoiled gradient-recalled echo imaging with physeal mapping. The cause, bone involved, radiographic appearance, and surgical interventions (60/111) were also correlated. Data were analyzed with the two-tailed Fisher's exact test. Posttraumatic bridges, accounting for 70% (78/111) of patients, were most often distal, especially of the tibia (n = 43) and femur (n = 14), whereas those due to the other miscellaneous causes were more frequently proximal (p < 0.0001). The position of the bridge in the physis was related to the bone involved (p < 0.0001). Sixty-five percent of distal tibial bridges involved the anteromedial physis, whereas 60% of the distal femoral arrests were central. Larger bridges had higher T1 signal intensity (p < 0.008). Oblique growth recovery lines were seen exclusively with bridges involving the peripheral physis (p = 0.002) and smaller, more potentially resectable bridges. Metaphyseal cartilaginous tongues were seen with all causes, but avascular necrosis was exclusively posttraumatic (p = 0.03). Signal characteristics and bridge size did not vary with the cause. Premature physeal bony bridging in children is most often posttraumatic and disproportionately involves the distal tibia and femur where bridges tend to develop at the sites of earliest physiologic closure, namely anteromedially and centrally, respectively. MR imaging, especially with the use of fat-suppressed 3D spoiled gradient-recalled echo imaging, exquisitely shows the growth disturbance and associated abnormalities that may follow physeal injury and guides surgical management.

IceBridge: Bringing a Field Campaign Home

NASA Astrophysics Data System (ADS)

Woods, J.; Beck, J.; Bartholow, S.

2015-12-01

IceBridge, a six-year NASA mission, is the largest airborne survey of Earth's polar ice ever flown. It will yield an unprecedented three-dimensional view of Arctic and Antarctic ice sheets, ice shelves and sea ice. These flights will provide a yearly, multi-instrument look at the behavior of the rapidly changing features of the Greenland and Antarctic ice. Data collected during IceBridge will help scientists bridge the gap in polar observations between NASA's Ice, Cloud and Land Elevation Satellite (ICESat) -- in orbit since 2003 -- and ICESat-2, planned for 2017. ICESat stopped collecting science data in 2009, making IceBridge critical for ensuring a continuous series of observations. IceBridge will use airborne instruments to map Arctic and Antarctic areas once a year at a minimum, with new campaigns being developed during the Arctic melt season. IceBridge flights are conducted in the spring and summer for the Arctic and in the fall over Antarctica. Other smaller airborne surveys around the world are also part of the IceBridge campaign. IceBridge actively engages the public and educators through a variety of outlets ranging from communications strategies through social media outlets, to larger organized efforts such as PolarTREC. In field activities include blog posts, photo updates, in flight chat sessions, and more intensive live events to include google hangouts, where field team members can interact with the public during a scheduled broadcast. The IceBridge team provides scientists and other team members with the training and support to become communicators in their own right. There is an exciting new initiative where IceBridge will be collaborating with Undergraduate and Graduate students to integrate the next generation of scientists and communicators into the Science Teams. This will be explored through partnerships with institutions that are interested in mentoring through project based initiatives.

Investigation, Modeling and Validation of Digital Bridge for a New Generation Hot-Wire Anemometer

NASA Astrophysics Data System (ADS)

Joshi, Karthik Kamalakar

The Digital Bridge Thermal Anemometer (DBTA) is a new generation anemometer that uses advanced electronics and a modified half-Wheatstone bridge configuration, specifically a sensor and a shunt resistor in series. This allows the miniaturization of the anemometer and the communication between host computer and anemometer is carried out using serial or ethernet which eliminates the noise due to the use of long cables in conventional anemometer and the digital data sent to host computer is immune to electrical noise. In the new configuration the potential drop across a shunt resistor is used to control the bridge. This thesis is confined to the anemometer used in constant temperature (CT) mode. The heat transfer relations are studied and new expressions are developed based on the new configuration of the bridge using perturbation analysis. The theoretical plant model of a commercially available sensor and a custom built sensor are derived and quantified. The plant model is used to design a controller to control the plant in closed-loop using feedback. To test the performance of the modified sensor used with a "generation-I" bridge and DAQ, an experiment was conducted. The controller was implemented in a user interface in LabVIEW. The test is to compare the results between a conventional TSI sensor with an IFA 300 anemometer and the setup describe above, in the wake behind a circular cylinder. Performance of the DBTA is satisfactory at low frequencies. A user interface capable of communicating with the anemometer to control the operation and collect data generated by anemometer is developed in LabVIEW.

Cognitive Development Assignment: Building Bridges between Chinese-Americans and Elementary School Classrooms.

ERIC Educational Resources Information Center

Schirmer, John

Elementary schools are ideal places to build the bridges between Chinese-Americans and the larger society. Studying the history of Chinese-Americans, examining their many contributions to the United States, and studying the contemporary Chinese-American population are good places to start. There are many books available to help students understand…

Development of LRFD procedures for bridge pile foundations in Iowa - volume III : recommended resistance factors with consideration of construction control and setup.

DOT National Transportation Integrated Search

2012-02-01

The Federal Highway Administration (FHWA) mandated utilizing the Load and Resistance Factor Design (LRFD) approach for all new bridges initiated in the United States after October 1, 2007. As a result, there has been a progressive move among state De...

Testing of New Bridge Rail and Transition Designs Vol. XIII Appendix L 32-in (813-mm) Thrie-Beam Transition

DOT National Transportation Integrated Search

1997-06-01

This report presents the results of a State Planning and Research (SP&R) pooled-fund study to develop safer bridge rail and transition designsThis pooled-fund study was sponsored by the Federal Highway Administration, 23 States, and the District of C...

A Summer Bridge Program for Underprepared First-Year Students: Confidence, Community, and Re-Enrollment

ERIC Educational Resources Information Center

Suzuki, Anne; Amrein-Beardsley, Audrey; Perry, Nancy J.

2012-01-01

This quasi-experimental, action-research study explored a five-week pre-enrollment initiative called the Pathways Summer Bridge (PSB) Program in the New College of Interdisciplinary Arts and Sciences at Arizona State University (ASU). Theoretically framed and developed using the six components of Tinto's (1993) longitudinal model of institutional…

Building Bridges between Neuroscience, Cognition and Education with Predictive Modeling

ERIC Educational Resources Information Center

Stringer, Steve; Tommerdahl, Jodi

2015-01-01

As the field of Mind, Brain, and Education seeks new ways to credibly bridge the gap between neuroscience, the cognitive sciences, and education, various connections are being developed and tested. This article presents a framework and offers examples of one approach, predictive modeling within a virtual educational system that can include…

Double hetero-Michael addition of N-substituted hydroxylamines to quinone monoketals: synthesis of bridged isoxazolidines.

PubMed

Yin, Zhiwei; Zhang, Jinzhu; Wu, Jing; Liu, Che; Sioson, Kate; Devany, Matthew; Hu, Chunhua; Zheng, Shengping

2013-07-19

A general synthesis of bridged isoxazolidines from a double hetero-Michael addition of N-substituted hydroxylamines to quinone monoketals has been developed. The different addition order of N-benzylhydroxylamine and N-Boc hydroxylamine is also discussed. Moreover, the various functionalities in the isoxazolidine products allow facile derivatization.

Understanding Customer Product Choices: A Case Study Using the Analytical Hierarchy Process

Treesearch

Robert L. Smith; Robert J. Bush; Daniel L. Schmoldt

1996-01-01

The Analytical Hierarchy Process (AHP) was used to characterize the bridge material selection decisions of highway officials across the United States. Understanding product choices by utilizing the AHP allowed us to develop strategies for increasing the use of timber in bridge construction. State Department of Transportation engineers, private consulting engineers, and...

A Narrative of Teacher Education in Canada: Multiculturalism, Technology, Bridging Theory and Practice

ERIC Educational Resources Information Center

Howe, Edward R.

2014-01-01

This narrative paper investigates a number of enduring and emerging themes reflecting teacher education in Canada over the past 40 years, including changes in information and communication technology, bridging gaps in theory and practice, English as a second language, French immersion and multicultural teacher development. Canadian teacher…

Crossing the Bridge: GED Credentials and Postsecondary Educational Outcomes. Year One Report

ERIC Educational Resources Information Center

Patterson, Margaret Becker; Zhang, Jizhi; Song, Wei; Guison-Dowdy, Anne

2010-01-01

For most high school non-completers, the GED[R] credential provides a bridge to postsecondary education, but little is known about how successfully GED (General Educational Development) Test candidates make that transition and whether enrollment rates change with time. The American Council on Education (ACE) has begun a three-year longitudinal…

75 FR 4612 - Agency Information Collection Activities: Notice of Request for Extension of Currently Approved...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-28

... construction time and traffic congestion; C. The development of engineering design criteria for innovative products, materials, and structural systems for use in highway bridges and structures; D. The reduction of... construction, repair, and rehabilitation of bridges and other highway structures. This program was funded by...

Build a Winning Hand

ERIC Educational Resources Information Center

Glover, Sandy

2005-01-01

What do poker and bridge have in common? Both are card games that originated in Europe (although poker's modern form developed in the frontier towns of the American West, while bridge still reflects its British heritage). Both use a regular 52-card playing deck, both involve bidding, and both have experienced renewed popularity in recent years.…

Innovative Contextualized Curriculum for a CNA to LPN Bridge Course. Promising Practice

ERIC Educational Resources Information Center

Office of Community College Research and Leadership, 2010

2010-01-01

As a pilot site selected to participate in Illinois' Shifting Gears (SG) initiative in 2007, Oakton Community College (OCC) partnered with Presbyterian Homes to develop a bridge course to prepare a cadre of their employed Certified Nursing Assistants (CNAs) to enter college-credit prerequisite courses to a Practical Nursing program. Oakton…

Reading?...Pah! (I Got It!): Innovative Reading Techniques for Successful Deaf Readers.

ERIC Educational Resources Information Center

Schimmel, Connie (Ruth) S.; Edwards, Sandra G.; Prickett, Hugh T.

1999-01-01

A reading program utilizing five components (a shortcut to phonemic awareness, Adapted Dolch words, Bridge lists and the Bridging process, reading comprehension, and American Sign Language development/language experience stories) resulted in dramatic gains in the reading levels of 48 elementary students at a residential school for the deaf.…

Wood in transportation program-- an overview

Treesearch

Sheila Rimal Duwadi; Michael A. Ritter; Edward Cesa

2000-01-01

Research and demonstration bridge projects to further develop wood for transportation structures increased substantially in the United States in 1988 under a legislative action by the U.S. Congress known as the Timber Bridge Initiative. This program, renamed the Wood in Transportation Program, continues today and is administered by the Forest Service. FHWA became...

Integrated remote sensing and visualization (IRSV) system for transportation infrastructure operations and management, phase two, volume 3 : advanced consideration in LiDAR technology for bridge evaluation.

DOT National Transportation Integrated Search

2012-03-01

This report describes Phase Two enhancement of terrestrial LiDAR scanning for bridge damage : evaluation that was initially developed in Phase One. Considering the spatial and reflectivity : information contained in LiDAR scans, two detection algorit...

Implementing statistical analysis in multi-channel acoustic impact-echo testing of concrete bridge decks: Determining thresholds for delamination detection

NASA Astrophysics Data System (ADS)

Hendricks, Lorin; Spencer Guthrie, W.; Mazzeo, Brian

2018-04-01

An automated acoustic impact-echo testing device with seven channels has been developed for faster surveying of bridge decks. Due to potential variations in bridge deck overlay thickness, varying conditions between testing passes, and occasional imprecise equipment calibrations, a method that can account for variations in deck properties and testing conditions was necessary to correctly interpret the acoustic data. A new methodology involving statistical analyses was therefore developed. After acoustic impact-echo data are collected and analyzed, the results are normalized by the median for each channel, a Gaussian distribution is fit to the histogram of the data, and the Kullback-Leibler divergence test or Otsu's method is then used to determine the optimum threshold for differentiating between intact and delaminated concrete. The new methodology was successfully applied to individual channels of previously unusable acoustic impact-echo data obtained from a three-lane interstate bridge deck surfaced with a polymer overlay, and the resulting delamination map compared very favorably with the results of a manual deck sounding survey.

Clear-Water Contraction Scour at Selected Bridge Sites in the Black Prairie Belt of the Coastal Plain in Alabama, 2006

USGS Publications Warehouse

Lee, K.G.; Hedgecock, T.S.

2008-01-01

The U.S. Geological Survey, in cooperation with the Alabama Department of Transportation, made observations of clear-water contraction scour at 25 bridge sites in the Black Prairie Belt of the Coastal Plain of Alabama. These bridge sites consisted of 54 hydraulic structures, of which 37 have measurable scour holes. Observed scour depths ranged from 1.4 to 10.4 feet. Theoretical clear-water contraction-scour depths were computed for each bridge and compared with observed scour. This comparison showed that theoretical scour depths, in general, exceeded the observed scour depths by about 475 percent. Variables determined to be important in developing scour in laboratory studies along with several other hydraulic variables were investigated to understand their influence within the Alabama field data. The strongest explanatory variables for clear-water contraction scour were channel-contraction ratio and velocity index. Envelope curves were developed relating both of these explanatory variables to observed scour. These envelope curves provide useful tools for assessing reasonable ranges of scour depth in the Black Prairie Belt of Alabama.

Demonstration of a roving-host wireless sensor network for rapid assessment monitoring of structural health

NASA Astrophysics Data System (ADS)

Mascarenas, David D. L.; Flynn, Eric; Lin, Kaisen; Farinholt, Kevin; Park, Gyuhae; Gupta, Rajesh; Todd, Michael; Farrar, Charles

2008-03-01

A major challenge impeding the deployment of wireless sensor networks for structural health monitoring (SHM) is developing means to supply power to the sensor nodes in a cost-effective manner. In this work an initial test of a roving-host wireless sensor network was performed on a bridge near Truth or Consequences, NM in August of 2007. The roving-host wireless sensor network features a radio controlled helicopter responsible for wirelessly delivering energy to sensor nodes on an "as-needed" basis. In addition, the helicopter also serves as a central data repository and processing center for the information collected by the sensor network. The sensor nodes used on the bridge were developed for measuring the peak displacement of the bridge, as well as measuring the preload of some of the bolted joints in the bridge. These sensors and sensor nodes were specifically designed to be able to operate from energy supplied wirelessly from the helicopter. The ultimate goal of this research is to ease the requirement for battery power supplies in wireless sensor networks.

Minimum depth of soil cover above long-span soil-steel railway bridges

NASA Astrophysics Data System (ADS)

Esmaeili, Morteza; Zakeri, Jabbar Ali; Abdulrazagh, Parisa Haji

2013-12-01

Recently, soil-steel bridges have become more commonly used as railway-highway crossings because of their economical advantages and short construction period compared with traditional bridges. The currently developed formula for determining the minimum depth of covers by existing codes is typically based on vehicle loads and non-stiffened panels and takes into consideration the geometrical shape of the metal structure to avoid the failure of soil cover above a soil-steel bridge. The effects of spans larger than 8 m or more stiffened panels due to railway loads that maintain a safe railway track have not been accounted for in the minimum cover formulas and are the subject of this paper. For this study, two-dimensional finite element (FE) analyses of four low-profile arches and four box culverts with spans larger than 8 m were performed to develop new patterns for the minimum depth of soil cover by considering the serviceability criterion of the railway track. Using the least-squares method, new formulas were then developed for low-profile arches and box culverts and were compared with Canadian Highway Bridge Design Code formulas. Finally, a series of three-dimensional (3D) finite element FE analyses were carried out to control the out-of-plane buckling in the steel plates due to the 3D pattern of train loads. The results show that the out-of-plane bending does not control the buckling behavior of the steel plates, so the proposed equations for minimum depth of cover can be appropriately used for practical purposes.

Tooth brush abrasion of paint-on resins for shade modification of crown and bridge resins.

PubMed

Fujii, Koichi; Ban, Seiji; McCabe, John F

2003-09-01

The purpose of this study was to evaluate the surface roughness and resistance to toothbrush abrasion of three experimental paint-on composite resins developed for the shade modification of crown and bridge resins. The paint-on resins had less filler volume fraction than restorative composites or the crown and bridge resins and consequently were of low viscosity. The maximum surface roughness (Rmax) and the maximum depth loss by abrasion for the paint-on resins following 40,000 cycles of brushing ranged from 2.45 to 4.07 microm and 8.63 to 13.67 microm, respectively. Rmax values were 37.7-67.5% lower than that for the crown and bridge resin subjected to the same test. Wear depth was 19.9-49.4% lower than for the crown and bridge resin. These results suggest that the paint-on resins are expected to have adequate resistance to toothbrush abrasion and may therefore be suitable for clinical use.

Stream Stability and Scour Assessments at Bridges in Massachusetts

USGS Publications Warehouse

Parker, Gene W.; Bratton, Lisa; Armstrong, David S.

1997-01-01

In 1989, the Federal Highway Administration mandated that every state establish a program to evaluate the vulnerability to floods of all bridges over water. The Massachusetts Highway Department entered into a cooperative effort with the U.S. Geological Survey to comply with this mandate. Geomorphic and hydraulic characteristics were collected and were used to assess the processes that affect stream stability and current scour problems and potential near 2,361 bridge sites in Massachusetts. As a result of these assessments, the Massachusetts Highway Department will prioritize the bridge inventory for action regarding scour safety. A data base was prepared that includes the geomorphic and hydraulic data collected during field assessments. In addition to the data base, this report includes the historical development of the bridge scour program, the methods used for data collection during assessments, the methods used for quality assurance and quality control, and how the data base was digitally formatted to be presented on a CD-ROM. A user's guide provides assistance in the use of this electronic data base and report.

Efficient field testing for load rating railroad bridges

NASA Astrophysics Data System (ADS)

Schulz, Jeffrey L.; Brett C., Commander

1995-06-01

As the condition of our infrastructure continues to deteriorate, and the loads carried by our bridges continue to increase, an ever growing number of railroad and highway bridges require load limits. With safety and transportation costs at both ends of the spectrum. the need for accurate load rating is paramount. This paper describes a method that has been developed for efficient load testing and evaluation of short- and medium-span bridges. Through the use of a specially-designed structural testing system and efficient load test procedures, a typical bridge can be instrumented and tested at 64 points in less than one working day and with minimum impact on rail traffic. Various techniques are available to evaluate structural properties and obtain a realistic model. With field data, a simple finite element model is 'calibrated' and its accuracy is verified. Appropriate design and rating loads are applied to the resulting model and stress predictions are made. This technique has been performed on numerous structures to address specific problems and to provide accurate load ratings. The merits and limitations of this approach are discussed in the context of actual examples of both rail and highway bridges that were tested and evaluated.

Ecological bridges and barriers in pelagic ecosystems

NASA Astrophysics Data System (ADS)

Briscoe, Dana K.; Hobday, Alistair J.; Carlisle, Aaron; Scales, Kylie; Eveson, J. Paige; Arrizabalaga, Haritz; Druon, Jean Noel; Fromentin, Jean-Marc

2017-06-01

Many highly mobile species are known to use persistent pathways or corridors to move between habitat patches in which conditions are favorable for particular activities, such as breeding or foraging. In the marine realm, environmental variability can lead to the development of temporary periods of anomalous oceanographic conditions that can connect individuals to areas of habitat outside a population's usual range, or alternatively, restrict individuals from areas usually within their range, thus acting as ecological bridges or ecological barriers. These temporary features can result in novel or irregular trophic interactions and changes in population spatial dynamics, and, therefore, may have significant implications for management of marine ecosystems. Here, we provide evidence of ecological bridges and barriers in different ocean regions, drawing upon five case studies in which particular oceanographic conditions have facilitated or restricted the movements of individuals from highly migratory species. We discuss the potential population-level significance of ecological bridges and barriers, with respect to the life history characteristics of different species, and inter- and intra-population variability in habitat use. Finally, we summarize the persistence of bridge dynamics with time, our ability to monitor bridges and barriers in a changing climate, and implications for forecasting future climate-mediated ecosystem change.