A New Optimization Approach to Enhance Seismic Performance of Lead Rubber Bearing-Isolated Steel Moment-Resisting Frames Under Extreme Events

This study presents an optimal design approach of lead rubber bearings (LRBs) for frame structures. The proposed approach involves a bi-objective optimization problem by maximizing the isolation efficiency along with minimization of peak bearing displacement. Further, a varying weight factor approach is proposed to target multiple performance objectives under different hazard levels of ground excitation. The optimal yield strength of LRBs for the considered frames is selected such that the total deviation of both objectives with respect to their specified limits is within 5%. Finally, it has been demonstrated that the proposed approach is generic in nature and valid for different superstructure flexibility and damping when subjected to ground motions of varying hazard levels.