Optimum Design of Structures Against Earthquake by a Modified Genetic Algorithm Using Wavelet Networks

Optimum design of structures against earthquake is achieved by a modified genetic algorithm. Some features of the simulated annealing are used to control various parameters of the genetic algorithm. To reduce the computational work, a fast wavelet transform is used by which the number of points in the earthquake record is decreased. The record is decomposed into two parts. One part contains the low frequency of the record, and the other contains the high frequency of the record. The low frequency part of the record is used for dynamic analysis. Then using a wavelet networks the dynamic responses of the structures are approximated. By such approximation, the dynamic analysis of the structure is not necessary during the optimization process. The wavelet neural networks have been employed as a general approximation tool for the time history dynamic analysis. A number of structures are designed for optimal weight and the results are compared with exact dynamic analysis.