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Recent damaging earthquakes in the United States and abroad have demonstrated 4S_ -9&z
the earthquake vulnerability of highway bridges that were designed to existing seismic s I ,!+
codes. To address this inadequate performance, extensive research programs have been *S$v SDJCW
carried out. These programs have advanced the state of the art to the point where a new ~9X^3 .nI
specification for seismic design is necessary to take advantage of new insight into U& ?hG>
ground motion and geotechnical effects, improved performance criteria, and more @AyteHK
advanced analytical and design methodologies. SI (f&T(
The objective of this research was to enhance safety and economy through the ZsmOn#`=^}
development of new load and resistance factor design (LRFD) specifications and commentary }^"6 :;,
for the seismic design of bridges. The research considered design philosophy 2RiJ m"
and performance criteria, seismic loads and site effects, analysis and modeling, and .;#T<S "
design requirements. The specifications are nationally applicable with provisions for r p N b.
all seismic zones and are intended to be integrated into the AASHTO LRFD Bridge q=1 N&#R G
Design Specifications. .`or^`X3
The research was performed by a joint venture of the Applied Technology Council h`[$
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and the Multidisciplinary Center for Earthquake Engineering Research. The report [ks_wvY:'
fully documents the methodology used to develop the recommended specifications. ,75)
The recommended specifications provided the technical basis for a stand-alone set of m]p{]6h
provisions prepared by the ATC/MCEER Joint Venture titled “Recommended LRFD *~rj!N?;
Guidelines for the Seismic Design of Highway Bridges.” AASHTO will consider these Q*ITs!~Z
provisions for adoption as a Guide Specification in 2002.
