Dynamic behavior of high arch dams under recorded seismic accelerograms. Study on the influence of reservoir water level

Abstract

In this paper the seismic response of a large arch dam (290 m high), located in a high seismicity region, is analysed. The goal is to study the influence of the reservoir water level in the dam’s dynamic response under recorded seismic accelerograms. The numerical calculations are carried out using a 3D finite element program (DamDySSA3.0), developed in MATLAB, for linear dynamic analysis of arch dams. The 3DFEM model is based on a formulation in pressures and displacements, considering a state space approach to solve the coupled eigenproblem with damping, while the seismic response is computed by means of direct integration in time domain using the Newmark method. The dam-reservoir-foundation system is discretized using cubic 3D finite elements with 20 nodal points. The seismic analysis of the dam is performed for the Jiashi earthquake (April5, 1997), using the recorded seismic accelerogram as input, and considering two different reservoir water levels, a massless foundation and a global damping of about 5%. The main numerical results are presented, including displacement and acceleration time histories, as well as the hoop and cantilever stresses envelopes.