Shape optimal design of materially nonlinear arch dams including dam-water-foundation rock interaction using an improved PSO algorithm

An efficient optimization procedure is proposed to find the optimal shape of arch dams including dam-water-foundation rock interaction subject to earthquake. The arch dam is treated as a three-dimensional structure involving the material nonlinearity effects. For this purpose, the nonlinear behavior of the dam concrete is idealized as an elasto-plastic material using the Drucker-Prager model. In order to reduce the computational cost of optimization process, a wavelet back propagation (WBP) neural network is designed to approximate the dam response instead of directly evaluating it by a time-consuming finite element analysis (FEA). An improved particle swarm optimization (IPSO) is also presented. In test example, the computational merits of the proposed methodology for optimizing an existing arch dam are demonstrated.