Optimal design of structures under earthquake loads using basic modal displacements method enhanced by fuzzy c-means clustering

Abstract

The achievement of optimal design of structures against earthquake loading is investigated by evaluating the dynamic response. First, the paper presents an efficient preliminary technique called basic modal displacements (BMD) method to evaluate the dynamic history response. Second, a fuzzy version of BMD is developed as the premier method for prediction of peak response value of structures to be used within genetic algorithm (GA) optimization. In BMD the seismic response of a new design of structure is approximated by revising exact modal responses of the primary design of structure referred to as base model. In the other proposed method called clustered basic modal displacements (CBMD) the accuracy of BMD method to evaluate the maximum response is significantly improved by selection of different base models for created structures in the optimization process. In CBMD the base models are selected using fuzzy c-means clustering algorithm. Three structures are designed for optimal weight using GA. Results show that the proposed approach, (CBMD), is successful comparing to those found in the literature.