Investigation of the effects of surface gravity waves on the distribution of hydrodynamic pressures by the finite element method : case of a vertical rigid dam

Abstract

This study examines the influence of surface gravity waves on the hydrodynamic pressures exerted on a rigid vertical dam during horizontal ground motions. Using the Finite Element Method for both incompressible and compressible fluid models, hydrodynamic responses are quantified. By accounting for surface-wave effects through a linearized free-surface condition, the analysis ensures their consistent influence. The El Fodda gravity dam serves as a case study, with outcomes assessed in both the time and frequency domains to highlight critical impacts, comparing situations with and without surface wave effects. These findings provide a foundation for interpreting how different wave effects manifest under various conditions. Building on these results, the analysis shows that surface waves have the most influence at low frequencies. At these levels, there is a substantial reduction in base pressures. As excitation frequency increases, their effect weakens, and compressibility governs the response, especially during seismic events. This behavior matches trends reported in the specialized literature. It highlights the need to distinguish surface-waves and compressional effects when assessing dam safety.