InTrans / Aug 14, 2018

Performance of steel, concrete, prestressed concrete and timber bridges

The National Bridge Inventory (NBl) in the United States is a comprehensive document that maintains inventory records on all bridges 20 ft (>6 m) or greater in length. Although its records are primarily used by individual states and the Federal government for assessing bridge condition and assigning funding to future projects, the NBI has much useful data that can be used for other purposes, such as developing historical
trends in bridge construction, adequacy, and longevity. Recently, the USDA Forest Service, Forest Products laboratory (FPL), in cooperation with the USDA Forest Service
Timber Bridge lnformetion Resource Center, completed an analysis of the 1992 NBI to determine historical characteristics of concrete, steel, prestressed concrete, and timber bridges. Comparisons of bridge performance based on historical data were investigsted and are presented in is paper. Analysis on material usage, structural and functional adequacy, and longevity are included. The construction and performance trends revealed by the data will be useful to bridge designers and managers.