Efficient Robust Optimization of Structures Subjected to Earthquake Load and Characterized by Uncertain Bounded System Parameters

Abstract

An efficient robust design optimization (RDO) procedure is proposed in the framework of an adaptive response surface method (RSM) for structures subjected to earthquake load and characterized by uncertain but bounded system parameters. The basic idea of the proposed RDO approach is to improve the robustness of a design by using a new dispersion index which utilizes the relative importance of the gradients of the performance function. The same concept is also applied to the constraints. The repeated computations of stochastic responses and their sensitivities for evaluating the stochastic constraint of the associated optimization problem are efficiently obtained in the framework of an adaptive RSM. The proposed RDO approach is elucidated through the optimization of a three-storied concrete frame structure. The numerical study depicts that the proposed RDO results are in conformity with the conventional RDO results. However, definite improvements are achieved in terms of robustness and computational time requirements indicating its efficiency over the conventional RDO approach.