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Recent damaging earthquakes in the United States and abroad have demonstrated o*)Sg6Yk
the earthquake vulnerability of highway bridges that were designed to existing seismic -8^qtB
codes. To address this inadequate performance, extensive research programs have been ketp9}u
carried out. These programs have advanced the state of the art to the point where a new ASHU0v
specification for seismic design is necessary to take advantage of new insight into dJgLS^1E
ground motion and geotechnical effects, improved performance criteria, and more f(pq`v^-n
advanced analytical and design methodologies. _;03R{e*
The objective of this research was to enhance safety and economy through the J-
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development of new load and resistance factor design (LRFD) specifications and commentary 1<G+KC[F
for the seismic design of bridges. The research considered design philosophy YTa
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and performance criteria, seismic loads and site effects, analysis and modeling, and RKP,w%
design requirements. The specifications are nationally applicable with provisions for J[<Zy^"Y;
all seismic zones and are intended to be integrated into the AASHTO LRFD Bridge ]P3m=/w
Design Specifications. 5Rl\& G\
The research was performed by a joint venture of the Applied Technology Council $ztsb V}
and the Multidisciplinary Center for Earthquake Engineering Research. The report Jx5`0?
fully documents the methodology used to develop the recommended specifications. 'O(=Pz
The recommended specifications provided the technical basis for a stand-alone set of Ef#LRcG-Z
provisions prepared by the ATC/MCEER Joint Venture titled “Recommended LRFD Nhs!_-_I
Guidelines for the Seismic Design of Highway Bridges.” AASHTO will consider these ;+wB!/k,
provisions for adoption as a Guide Specification in 2002.