An approach for optimum performance-based seismic design of 3D steel moment frames

Abstract

An optimal performance-based design (PBD) of a three-dimensional (3D) structure requires repeated evaluation; thus, proposed approaches should attempt to significantly reduce the number of evaluations required during optimization. The current study proposes a multi-step approach for optimal PBD of a 3D steel moment frame in which the structure is examined at each step for one performance level in a specific direction. To advance to the next step, the acceptance criteria for linear static analysis of the steel moment frame from ASCE 41-17 should have been satisfied in the previous step. An objective function has been formulated using the proposed stepped penalty function to achieve a feasible space, the value of which can be determined based on the number of unexamined steps. Finally, the optimal PBDs for 3D three-story and nine-story steel moment frames were evaluated using EVPS and WSA metaheuristic algorithms to evaluate the proposed process. The final optimal designs were assessed using the acceptance criteria of nonlinear static analysis. The number of performance level evaluations in each direction during optimization showed approximately 60 % and 70 % reductions during analysis by the proposed method for the WSA and EVPS algorithms, respectively.