Federal, State, and local transportation agencies are responsible for the stewardship and management of the more than 590,000 bridges in the United States. This involves many planning, operational, maintenance, and economic challenges.
To help overcome these challenges and foster the next generation of bridge and bridge management systems, the Federal Highway Administration's (FHWA's) Office of Infrastructure Research and Development launched the Long-Term Bridge Performance (LTBP) program in April 2008, a major strategic initiative designated as a flagship research project. The LTBP program is intended to be a minimum 20-year research effort, with the global objective of collecting scientific-quality data from the Nation's highway bridges, as critical node-points of the highway transportation network. The data and information collected in this program will provide a more detailed and timely picture of bridge health, improve knowledge of bridge performance, and ultimately promote the safety, mobility, longevity, and reliability of the Nation's highway transportation assets.
The program was created in legislation for surface transportation enacted by the U.S. Congress in 2005: the Safe, Accountable, Flexible, and Efficient Transportation Equity Act: A Legacy for Users (SAFETEA-LU). Funding will continue for the LTBP program in the current legislation, Moving Ahead for Progress in the 21st Century Act (MAP-21).
Federal Highway Administration's (FHWA's) National Bridge Inspection Standards (NBIS) facilitated the creation of the National Bridge Inventory (NBI), one of the most comprehensive sources of bridge information in the world. The NBI contains information on the conditions of more than 600,000 bridges, tunnels, and culverts located on public roads. In 2012, according to the NBI, there were approximately 151,497 structurally deficient or functionally obsolete bridges. This number is likely to increase in coming years due in large part to increased traffic demand, continued bridge aging and deterioration, and limited funds for rehabilitation and maintenance.
A number of States have adopted and implemented the American Association of State Highway and Transportation Officials' (AASHTO) AASHTOWare® Bridge Management software (formerly Pontis) or a similar system with advanced asset management decisionmaking capabilities. Some States augment the NBI data used in advanced bridge management systems by also collecting element level bridge data. Even with these bridge management tools and data, however, there remain many unknowns about the performance and degradation of structures and materials over time, and the effectiveness of maintenance, repair, and rehabilitation strategies for a given component or a complete bridge system. In addition, with the recent move to higher performance materials and advanced structural systems, high-level, long-term performance and durability are assumed, but not demonstrated at this time.
For the Nation's bridge network to meet these increasing demands without similar increases in funding, future bridge management systems will require improved life-cycle cost and deterioration models, and information on the effectiveness of maintenance and repair strategies. Such improvements will require high-quality quantitative data on which to base the development of new models and decisionmaking algorithms.
The objective of the LTBP program is to compile a comprehensive database of quantitative information from a representative sample of bridges nationwide, looking at every element of a bridge. By taking a holistic approach and analyzing all of the physical and functional variables that affect bridge performance, the study will provide a more detailed and timely picture of bridge health and better bridge management tools.
Long-Term Bridge Performance researchers conduct detailed periodic inspections, monitoring, and evaluation of the population of bridges representing the national bridge inventory by taking advantage of nondestructive evaluation (NDE) techniques and visual inspections. Nondestructive evaluation techniques are used to detect flaws and corrosion inside the structures and cracks due to fatigue and corrosion, overloads, environmental conditions, etc. For selected bridges in the study, researchers conduct recurrent, periodic evaluations throughout the life of the program and may perform forensic autopsies of decommissioned bridges to learn more about their capacities, reliabilities, and failure modes.
The wealth of data collected through the LTBP program, and the subsequent data analysis, will:
Ultimately, improved understanding of bridge performance will promote safety, mobility, longevity, and reliability of the Nation's highway transportation assets and allow bridge owners to make better data-driven decisions regarding their bridge inventory.
The research team will conduct the work in two phases to achieve the objectives of the FHWA LTBP program. These phases are:
The Developmental phase has been completed. In the pilot portion of the program (which is part of the Developmental phase), researchers validated protocols for data collection and management to ensure that all of the components needed to achieve the long-term objectives of the LTBP program are specified before initiating work on the large population of bridges nationwide.
Both phases require active engagement between the research team, FHWA, bridge owners (State DOTs), industry, and other government agencies. It is also essential to coordinate with other long-term strategic research programs undertaken by FHWA, AASHTO, Transportation Research Board (TRB), American Society of Civil Engineers, National Cooperative Highway Research Program, Second Strategic Highway Research Program (SHRP2), National Institute of Standards and Technology, National Science Foundation, and the U.S. Army Corps of Engineers.
The Bridge Portal is more than just a database. It not only contains bridge performance-related data mined from existing sources (National Bridge Inventory, State Highway Agency bridge element level data, national weather data, traffic data, weigh-in-motion data, bridge maintenance data, and other data sources), but it also serves as a central repository for all field data collected through the LTBP program. In addition, the Bridge Portal will also function as a research and decision-making tool by implementing bridge life cycle and deterioration modeling using both mined data sources as well as LTBP acquired field data to allow users to investigate bridge performance on many different levels.
The Federal Highway Administration, in partnership with Rutgers University’s Center for Advanced Infrastructure and Transportation (CAIT), developed a multifunctional nondestructive evaluation (NDE) platform to enhance condition assessment of concrete bridge decks. The RABIT™ Bridge Deck Assessment Tool was developed to deploy a suite of NDE technologies simultaneously.
A TRB LTBP Advisory Committee, and the three LTBP Expert Task Groups (ETGs) that advise the TRB Committee, were established to provide advice to FHWA and the research team on matters relating to LTBP program activities. The members of these groups were appointed by TRB, based on their technical expertise in bridge design, inspection, maintenance and preservation, management, NDE/nondestructive techniques, and structural health monitoring of bridges. [Coordination and Outreach]
The LTBP program is designed as a coordinated, collaborative, multi-institutional, and multidisciplinary effort with researchers in government, academia, and industry. The primary contractor for the LTBP Program Developmental Phase was Rutgers University's Center for Advanced Infrastructure and Transportation, in partnership with Parsons Brinckerhoff; the Utah Transportation Center; the Virginia Center for Transportation Innovation and Research; Arora and Associates, P.C.; the University of Delaware; and the technology provider, Advitam. These organizations were awarded a five-year contract for work conducted through 2012. Additionally, a contract has been awarded in support of the LTBP program, primarily to assist with the Long-Term Data Collection phase. The current Program Contractors can be found by clicking here.
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Hamid Ghasemi, Ph.D|
LTBP Program Manager
Turner-Fairbank Highway Research Center
6300 Georgetown Pike
McLean, VA 22101
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