A new optimization approach to enhance seismic performance of lead rubber bearing-isolated steel moment-resisting frames under extreme events

Abstract

This study presents an optimal design approach of lead rubber bearings (LRBs) for frame structures.The proposed approach involves a bi-objective optimizationproblem by maximizing the isolation efficiencyalong with minimization of peak bearing displacement.Further, a varying weight factor approach isproposed to target multiple performance objectivesunder different hazard levels of ground excitation.The optimal yield strength of LRBs for the consideredframes is selected such that the total deviation of bothobjectives with respect to their specified limits is within5%. Finally, it has been demonstrated that the proposedapproach is generic in nature and valid fordifferent superstructure flexibility and damping whensubjected to ground motions of varying hazard levels