This paper aims to define the non-linear response for concrete arch gravity dams, considering seismic actions as main external destabilizing actions.

The plastic degradation theory has been used to define the reduction of the elasto-plastic modulus during the hysteretic cycles. The parameters to apply the model are obtained from the literature and numerical analysis. In this sense, working with a reduction of the elasto-plastic modulus is useful to define the displacement of the structure. The seismic input has been obtained from probabilistic and deterministic seismic hazard analyses. For that, a series of several earthquakes have been chosen to perform the time–history analysis. The response of the structure blocks under four earthquakes has been made using a step-by-step direct integration. An application to Rules Dam has been made to test the method.

Results of the seismic analysis provide several specific accelerations for concrete arch gravity dams. Results of the structural show that in 2D analysis the maximum non-linear dam displacements reach value up to 27 cm, whereas for 3D analysis they reach up to 7 cm. Moreover, these cyclic displacements produce several accumulations of plastic deformations and cracks.