Nonlinear hydrodynamic effects on concrete dam

Abstract

Detailed nonlinear hydrodynamic analyses of a concrete gravity dam have been made. The effects of free surface flow and the nonlinearity of convective acceleration are included in the analyses. Not only nonlinear hydrodynamic pressures and the rise of the water surface but also the structural dynamic responses of the dam have been calculated. The records of four actual earthquakes were adopted as the exciting ground motions. The characteristics of the relationships between the hydrodynamic force coefficient, the rise of the water surface and the time history of the ground motion are studied. The hydrodynamic force coefficient on a rigid dam face can easily be predicted by the formula C F = 0.525 a h + a v . The rise of the water surface at the dam face is primarily due to ground displacement. The structural dynamic responses evaluated by the analyses with and without water surface effects were then compared. The surface wave effects of the fluid can be neglected in the dynamic structural analysis of a concrete gravity dam. However, the rise of the water surface (up to 2.7 m) could cause damage to boats and human safety in recreational areas, and hazards associated with the possible overtopping.