Seismic Response of Integral Abutment Bridges

The use of integral abutment bridges (IABs) is widespread throughout the U.S.; the Midwestern state of Illinois is no exception, with this bridge type commonly utilized in the state. The proximity of southern Illinois to the New Madrid Seismic Zone creates concerns about the earthquake-resistance of IABs in this region. Recent research concerning the seismic response of seat-type abutment bridges has determined that the failure of abutment bearings and backwalls are important fusing mechanisms under moderate to strong seismic loads. However, only limited research has been conducted on the seismic response of IABs (especially in Illinois), which do not have the abutment bearings that allow seat-type abutment bridges to behave in a quasi-isolated fashion. Through the use of site-specific ground motions developed for various locations in southern Illinois, along with a set of IAB models created in OpenSees, this paper presents preliminary data concerning the seismic structural behavior of an IAB designed per current IDOT procedures