Nonlinear Hydrodynamic Pressure on Dams

The dynamic interaction between nonlinear hydrodynamic pressures and the vibration of a concrete gravity dam is analyzed by coupling Euler's equations with a finite element model of the dam. The earthquake force components in the horizontal and vertical directions are cast as the forcing functions in the finite difference equations for fluid motion. The results are compared with those associated with a rigid dam motion. The pressure distributions are very sensitive to dam vibration and surface wave. For El Centra ground motion recorded on October 15, 1979, the calculated rise of the water surface on Pine Flat Dam was 8 ft (2.7 m), indicating a strong nonlinear effect on hydrodynamic pressures and the potential hazards of surface waves in the reservoir.