Multi-objective design optimization of steel moment frames considering seismic collapse safety

This study focuses on multi-objective performance-based seismic optimization of steel moment frames by an efficient algorithm. In the present study, an efficient framework is developed to find a Pareto front for multi-objective optimization problem of steel moment frames involving global damage index and initial cost as two conflicting objective functions. To this end, a new multi-objective algorithm is introduced and its efficiency is demonstrated trough a set of benchmark multi-objective truss design examples. Subsequently, a 6- and a 12-story steel moment frame are designed by the proposed algorithm. To evaluate the seismic performance and collapse capacity of the optimal designs, damage indices and incremental dynamic analysis are used and their seismic damage costs and adjusted collapse margin ratios are evaluated.