Seismic analysis of Cabril dam. Measured response and comparison with numerical results from Code_Aster and DamDySSA

Abstract

This paper presents a study on the seismic response of the 132 m high Cabril arch dam, for an earthquake measured in-situ with the installed Seismic and Structural Health Monitoring system (in operation since 2008). The measured acceleration time histories are compared with results from finite element analysis in various positions in the dam body, using the seismic accelerations recorded at the dam-rock interface as inputs. The numerical simulations are conducted using two programs: i) DamDySSA4.0, a 3D finite element program develop in LNEC for dynamic analysis of arch dams – the dam-reservoir-foundation system is simulated based on a coupled model, using a formulation in displacements and pressures, considering the substructure method to simulate the foundation; and ii) Code_Aster, a finite element program developed in EDF – dam-water interaction is considered based on the potential fluid approach and the mass of the foundation is taken into account with absorption of the waves radiating from the dam by viscous-spring boundaries around the foundation. The investigation is focused on the required damping ratios, in the dam and foundation, to fit the computed results to the measured response, which is a key aspect to consider in arch dam seismic analysis.