Long-Term Bridge Performance Program
With the passage of the Safe, Accountable, Flexible, Efficient Transportation Equity Act (SAFETEA-LU), the Federal Highway Administration (FHWA) Office of Infrastructure, Research and Development (R&D), is initiating the Long-Term Bridge Performance (LTBP) program.
The LTBP program is an ambitious 20-year research effort that is strategic in nature with specific short- and long-term goals. The program will include detailed inspection, periodic evaluation and testing, continuous monitoring, and forensic investigation of representative samples of bridges throughout the United States to capture and document their performance. This LTBP program will result in a high-quality, quantitative database, which will have an impact on the value, success, and efficiency of bridge management systems in the future.
Special Announcement
The FHWA has selected a lead technical team to execute the Long-Term Bridge Performance (LTBP) program. The anticipated result of the LTBP program is that it will significantly enhance our knowledge of bridge performance and will lead to the development of improved life-cycle cost and performance predictive models, better understanding of bridge deterioration, improved effectiveness of maintenance and repair strategies, provide support for improved design methods and bridge preservation practices, and facilitate development of the next generation of bridges and bridge management systems. For more information on the RFP, go to
https://www.fbo.gov/index?s=opportunity&mode=form&id=cdcc79ee84b9b37e8b9f5645f6dc2454&tab=core&_cview=1.
Need
FHWA’s National Bridge Inspection Standards (NBIS) facilitated the creation of one of the most comprehensive sources of bridge information in the world, the National Bridge Inventory (NBI). The NBI contains information on the condition of more than 590,000 bridges, tunnels, and culverts located on public roads. In 2005, according to the NBI, there were approximately 156,000 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® Pontis® bridge management system 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 performance models, and information on the effectiveness of maintenance and repair strategies. However, such improvements will require high-quality quantitative data on which to base the development of new models and decisionmaking algorithms.
Objective of the LTBP Program
The objective of the LTBP program is to collect, document, and make available high-quality quantitative performance data on a representative sample of bridges nationwide. Data will be collected through detailed inspections and evaluations, supplemented by a limited number of continuously monitored structures and forensic autopsies on decommissioned bridges. In the latter years of the program, the collected data will be analyzed to develop improved knowledge about bridge performance and degradation, better design methods and performance predictive models, and advanced management decisionmaking tools.
Specifically, the anticipation is that the LTBP program will provide a better understanding of bridge deterioration due to corrosion, fatigue, weather and exposure, and loads. The program also will provide information about the effectiveness of current maintenance and improvement strategies, and should lead to improving the operational performance of bridges with the potential to reduce congestion, delay, and crashes.
LTBP Program Components
At this time, a draft framework—which will define program activities and goals in both the short- and long-terms—for the LTBP program is being developed. FHWA will present the framework to key members and representatives of the highway bridge community for comment and recommendations in a series of workshops held in 2006 and early 2007. The framework will address the following specific issues:
- Program management and administration
- Specific data to be collected
- Types and number of bridges to be inspected and monitored
- Data quality and collection strategies
- Data management and archiving
- Data mining and analysis
- Data and information dissemination
- Opportunities for participation and collaboration
As noted, LTBP program will have three components of bridge monitoring and evaluation:
Periodically Inspected Bridges: Detailed inspection of these bridges will include visual inspection and the use of advanced nondestructive evaluation techniques to detect and document deterioration. The inspections will be conducted periodically with additional inspections performed when appropriate.
Instrumented Bridges: Continuous monitoring of these bridges will be conducted using sensing technology to measure and record their performance characteristics under routine traffic conditions, and during and after rare or extreme events.
Decommissioned Bridges: Forensic autopsies of these bridges will be conducted to learn more about their capacities, reliabilities, and failure modes.
Conclusions
The LTBP program will require considerable synergy and cooperation among and between FHWA, bridge owners, the bridge industry, and academia. If successful, the program will drive efforts that result in bridges that last longer, require less maintenance, and can be modified to accommodate changes in traffic or function much more quickly and far less intrusively than current technology allows.
For more information on the FHWA LTBP program, please contact Hamid Ghasemi, LTBP program manager, at (202) 493-3042, or via email at hamid.ghasemi@fhwa.dot.gov.
