Hydrodynamic Pressures on Gravity Dams from Random Excitation

Hydrodynamic pressures occurring on the upstream face of the dams under random earthquake forces are calculated considering dam-reservoir interaction in this paper.

The equations of motion of the coupled system are obtained by using the Lagrangian approach and the surface sloshing motion is taken into account in the
formulations. A concrete gravity dam is selected for the application. Displacement-based eight-noded solid and nine-noded fluid isoparametric quadrilateral finite elements are used in the finite element model of the dam reservoir interaction system.

The Pacoima Dam record S16E component recorded during the San Fernando
earthquake in 1971 is used as a ground motion. Random hydrodynamic pressures on the upstream face of the dam obtained from the horizontal and vertical ground motions are calculated respectively, and compared with the deterministic hydrodynamic pressures. Besides, the compressibility effect of the fluid on the random hydrodynamic
pressures is also investigated