Shape optimal design of arch dams including dam-water-foundation rock interaction using a grading strategy and approximation concepts

Optimal design of arch dams including dam-water-foundation rock interaction is achieved using the soft computing techniques. For this, linear dynamic behavior of arch dam-water-foundation rock system subjected to earthquake ground motion is simulated using the finite element method at first and then, to reduce the computational cost of optimization process, a wavelet back propagation neural network (WBPNN) is designed to predict the arch dam response instead of directly evaluating it by a time-consuming finite-element analysis (FEA). In order to enhance the performance generality of the neural network, a dam grading technique (DGT) is also introduced. To assess the computational efficiency of the proposed methodology for arch dam optimization, an actual arch dam is considered. The optimization is implemented via the simultaneous perturbation stochastic approximation (SPSA) algorithm for the various conditions of the interaction problem. Numerical results show the merits of the suggested techniques for arch dam optimization. It is also found that considering the dam-water-foundation rock interaction has an important role for safely designing an arch dam. (C) 2009 Elsevier Inc. All rights reserved.