Seismic Excitation of a Concrete Dam: Analysis of the Influence of Modelling Approaches and Concrete Material Non–linearity

Abstract

The theme of this numerical benchmark workshop is related to the seismic analysis of Pine Flat Dam. The dam consists of 47 concrete monoliths and can thus be numerically modelled as a 2D structure. The analysis in this paper is conducted using the commercial finite element solver ANSYS. A comparison between results achieved with the typically used massless foundation and the viscous spring model is given as well as a comparison between results achieved with linear and non-linear concrete material models. In the latter case, the damaged plasticity model for concrete according to Menetrey and Willam is used. It is shown that as long as the loading is weak to moderate, the linear material model can provide a first guess of the response. However, once the loading is moderate to strong, the effects of concrete damage and cracking are significant and the models neglecting material nonlinearity are too conservative regarding expected stresses and cannot predict the real system behavior. Regarding the influence of the analysis approach, a clear tendency for the massless foundation model to reach higher peak responses that the viscous spring model is documented. The latter seems more accurate but is also more complex to set up.