NCHRP Report 472, Comprehensive Specifications for the Seismic Design of Bridges, contains the findings of a study to develop recommended specifications for the seismic design of highway bridges. The report describes the research effort leading to the recommended specifications and discuses critical conceptual and technical issues. The material in this report will be of immediate interest to bridge-design specification writers and to bridge engineers concerned with the seismic design of highway bridges.

Recent damaging earthquakes in the United States and abroad have demonstrated the earthquake vulnerability of highway bridges that were designed to existing seismic codes. To address this inadequate performance, extensive research programs have been carried out. These programs have advanced the state of the art to the point where a new specification for seismic design is necessary to take advantage of new insight into ground motion and geotechnical effects, improved performance criteria, and more advanced analytical and design methodologies.

The objective of this research was to enhance safety and economy through the development of new load and resistance factor design (LRFD) specifications and commentary for the seismic design of bridges. The research considered design philosophy and performance criteria, seismic loads and site effects, analysis and modeling, and design requirements. The specifications are nationally applicable with provisions for all seismic zones. The recommended specifications are formatted for direct integration into the AASHTO LRFD Bridge Design Specifications and can be viewed by clicking on this icon.
LRFD Specifications

The research was performed by a joint venture of the Applied Technology Council and the Multidisciplinary Center for Earthquake Engineering Research. The recommended specifications provided the technical basis for a stand-alone set of provisions prepared by the ATC/MCEER Joint Venture titled "Recommended LRFD Guidelines for the Seismic Design of Highway Bridges." For information about that document contact Dr. Philip Yen, FHWA (wen-huei.yen@fhwa.dot.gov, 202/493-3056).