Metodologias para o cálculo sísmico não-linear de barragens de betão

Abstract

In this monograph the basic methodologies for the non-linear seismic analysis of concrete dams are presented.

The Finite Element Method is used to discretize the dam-foundation-reservoir ensemble, whereas the dynamic equations will be solved in the time domain according to implicit integration schemes, namely the Newmark method and the Hilber-Hughes-Taylor alpha method. For the non-linear problem a predictor multicorrector algorithm is adopted.

In view of the large scale computations inherent to dam analysis, a constitutive damage model for massive concrete is briefly presented.

Attention is devoted to the numerical noire which arises from direct time integration, and to its control through the algorithmic dissipation provied by the alpha method, or by a s stiffness proportional damping matrix which is updated to account for material degradation.

Special care is devoted to the simulation of the reservoir. Numerical modelling of the hydrodynamic effect is discussed in detail, either by means of pressure or displacement formulations, or even through the technique of the added masses form Westergaard.