3D effects on the seismic response of dam-reservoir systems

Conventional seismic analysis of gravity dams assumes that the behavior of the dam-water-soil system can be represented using a 2D model. The assumption is based on the fact that gravity dams are usually built with transversal joints that effectively allow the concrete blocks to behave independently from each other. However, reservoirs usually have a different width than the dam. In this paper, a simplified analytical model and a BEM model are used to investigate the influence of the reservoir geometry on the dam response. The results show that the reservoir shape strongly influences the seismic response of the dam, making it necessary to account for 3D effects in order to obtain accurate results. In particular, the 3D pressure and displacement responses can be quite higher than for the 2D model.