Seismic design of steel bridges

AASHTO provides two publications for the seismic design of steel bridges: the LRFD Bridge Design Specifications (AASHTO, 2012) and the Guide Specifications for LRFD Seismic Bridge Design (AASHTO, 2011). The seismic provisions in the LRFD Bridge Design Specifications, hereafter referred to as the LRFD Specifications, are based on the recommended guidelines in the ATC-6 report published in 1981 (ATC, 1981). The ATC study was initiated by the aftermath of the 1971 San Fernando earthquake that caused significant damages to reinforced concrete bridges. Since bridge substructures are typically made of reinforced concrete in high seismic regions in North America, the LRFD Specifications have been mainly focused on reinforced concrete bridges and the coverage of steel bridges is limited.