Analysis of Seismic Responses During Near-Source Ground Motions

Seismic responses can strongly determine damages of bridge structures, e.g. due to pounding and unseating of girders as observed in many major earthquakes in the past. In the investigations often uniform ground excitation and pounding at only one location are considered. Studies on the influence of non-uniform ground excitation on bridge responses are still very limited, and they are restricted to flat ground-surface condition. Influence of multi-sided pounding is also not much investigated. If the impediment effect of abutments is considered at all. The study reveals that commonly assumed girder stiffness for the end restraint overestimates the actual effective end-restraint stiffness. Non-linear elastomeric bearings can significantly reduce the adjacent girder relative displacements. A consideration of non-uniform excitation is essential for a realistic estimation of bridge response and damage potential.