Non-linear seismic behaviour of concrete gravity dams using coupled finite element-boundary element technique

In this paper, the seismic response of concrete gravity dams is presented using the concept of Continuum Damage Mechanics (CDM) and adopting the hybrid Finite ElementÐBoundary Element technique (FEÐBE). The Þnite element method is used for discretization of the near Þeld and the boundary element method is employed to model the semi-inÞnite far Þeld. Because of the non-linear nature of the discretizied equations of motion modiÞed NewtonÐRaphson approach has been used at each time step to linearize them. Damage evolution based on tensile principal strain using mesh-dependent hardening modulus technique is adopted to ensure the mesh objectivity and to calculate the accumulated damage. The methodology employed is shown to be computationally e¦cient and consistent in its treatment of both damage growth and damage propagation in gravity dams. Other important features considered in the analysis are: (1) realistic damage modelling for concrete that allows isotropic as well as anisotropic damage state and exhibits sti¤ness recovery upon load reversals. (2) softening initiation and strain softening criteria for concrete, and (3) proper modelling of semi-inÞnite foundation using FEÐBE method that allows to consider damÐfoundation interaction analysis. As an application of the proposed formulation a gravity dam has been analysed and the results are compared with di¤erent foundation sti¤nesses. The results of the analysis indicate the importance of including rock foundation in the seismic analysis of dams. Copyright