Impact of Spatial Variation of Ground Motions on the Seismic Performance of a Bridge Structure

Abstract

In earthquakes propagating seismic waves will arrive at adjacent supports at different time instants. Consequently, the ground motion will not excite all bridge components at the same time, but with a time delay. Since the soil development along the bridge is never uniform, the propagating waves will be altered by the different soil properties along the wave path. The bridge will therefore experience spatially non-uniform ground excitation with a coherency loss. The research focuses on the consequence of this non-uniform ground excitation for the response of a bridge structure. The abutment, bridge pier and adjacent abutment were excited by three separate large shake tables, respectively. The influence of the spatial variation of ground motions and the girder-abutment pounding on the seismic response is presented.