Optimum design of seismic isolation systems using metaheuristic search methods

This study addresses the optimum design of seismic isolated structures via metaheuristic search methods. Three recently developed bio-inspired search methods, namely crow search (CSA), whale optimization (WOA) and grey wolf optimizer (GWO), were employed to develop efficient design optimization algorithms for parameter optimization of seismic isolated structures. The developed design optimization algorithms have been applied to optimize a shear frame model with a base isolation system, where the main objective was to obtain isolation system parameters resulting in minimum roof acceleration without exceeding the isolation system displacement limits. The linear isolator system parameters, namely the damping ratio and isolator period, were optimized based on the time history analyses. The optimization procedure was performed for various isolation displacement limits and damping ratio ranges. The results obtained for this isolated structure by the three design optimization algorithms were compared with previously published results in the literature in order to achieve a verification of the developed algorithms. One of the main outcomes of this study is that the high damping ratio does not always guarantee optimum isolation parameters, while an optimum damping ratio is crucial for achieving the minimum roof acceleration.