Performance-Based Seismic Design Optimization of Steel MRFs Under System and Component Constraints Using the IWSA Algorithm

Performance-based seismic design optimization (PBSDO), as a topic of growing interest, is applied to steel moment-resisting frames (MRFs) using the improved water strider algorithm (IWSA). Herein, PBSDO is carried out according to ASCE 41-17 provisions considering life safety and collapse prevention (CP) performance levels. IWSA is an enhanced version of the recently developed metaheuristic called the water strider algorithm (WSA), inspired from the life cycle of these insects. Two other metaheuristics, enhanced colliding bodies optimization (ECBO) and particle swarm optimization, are selected for the comparative study. In the current article, for the first time, all the essential constraints to fully simulate the practical PBSDO problem in accordance with the ASCE 41-17 for steel MRFs are considered for these newly developed algorithms, i.e., WSA and IWSA, to challenge them for a complex problem. Two MRFs with 9 and 24 discrete variables are studied here for this purpose. The constraints include non-seismic ones, i.e., geometry and strength (component level), as well as the seismic ones which consist of the inter-story drift ratio (system level), force-controlled and deformation-controlled members' acceptance criteria (component level). Furthermore, the strong column-weak beam (SCWB) criterion and plastic hinge distribution are investigated for the optimal designs. An efficient method is proposed to solve these complicated problems by which ECBO and IWSA could successfully solve both problems. The results demonstrate the predominance of the CP acceptance criteria constraints in the optimization and showcase the superiority or competitiveness of IWSA over the other three metaheuristics revealing its efficiency for complex structural optimization problems.