IMPLEMENTATION OF SEISMIC DESIGN AND RETROFIT PROCEDURES FOR HIGHWAY BRIDGES

This is a summary of recent advances in earthquake bridge design which takes into account the performance of substructures under high lateral loads. Efforts by the Federal Highway Administration (FHWA) to provide training in the latest design and retrofit procedures are also described. It is noted that for earthquake design, the critical bridge elements are the substructure and foundations, and their connections to the superstructure. The past performance of bridges is reviewed, substructure and superstructure damage that can be caused by earthquakes is noted, and current seismic design philosophy is briefly discussed. Work to evaluate the seismic design and retrofit of highway structures include the following: development of a state-of-the-art, nationally accepted seismic design specification; development of comprehensive, practical guidelines for seismic retrofitting of bridges; and development of a user-firendly microcomputer program for seismic analysis of bridges.