Spatial variation input effects on seismic response of arch dams

In the present paper, the seismic response of an arch dam subjected to spatial variation of ground motions along the interface with its foundations is investigated. Recorded ground accelerations at the dam foundation interface of an arch dam were used for the purpose of this investigation. Topographic amplification between various points of the interface was studied by obtaining ratios of the response spectral displacement and spectral pseudo acceleration. Time shift and amplification between stations show the nonuniform nature of ground motions for large structures like dams. Recorded ground accelerations were interpolated for different nodes of the finite element model. The seismic responses of the Karun III dam subjected to multiple support excitations are determined. The results show that nonuniform ground acceleration can have extensive effects on dam behavior and can increase the responses. Pseudo static displacement is the dominant part of total displacement for points near the dam foundation interface; however, dynamic displacement is more significant for the middle part of the dam.