The Federal Highway Administration (FHWA) Long-Term Bridge Performance (LTBP) Program conducted a study on changes in bridge practices for reinforcing bars, in conjuncton with the National Concrete Bridge Council. This program, an effort by the .S. Congress under the Safe, Accountable, Flexible, Efficient Transportation Equity Act: A Legacy for Users, collects bridge data to help the bridge community better understand performance.
Field data for the LBTP Program has been collected since 1960 and highlight the changes/technological advances that have occurred in bridge building over time:
For example, if a bridge built in 1965 is outperforming a bridge built in 1978 (or vice versa), it would be helpful to understand what innovations and changes in practice occurred between these two dates that could affect bridge performance.