A simplified model for seismic resilience improvement of regional RC frame structures using seismic isolation

Seismic resilience of structures has become a critical issue in earthquake engineering worldwide, recently. RC frame structure, as a typical structure, is selected as the research object here. Considering the computational efficiency and accuracy, a simplified model for it was suggested and investigated with emphasis put on the critical requirements of seismic resilience of RC frames with seismic isolation, including the capacities of predicting critical design indices, seismic responses and resilient performance. Employing a basic case, the prediction accuracy of the widely-used hybrid simplified model based on shear beam (referred to as "HSS model" hereafter) was evaluated firstly. The results indicate that such model cannot predict the critical design index (i.e. base shear ratio) well. Furthermore, it is not capable of predicting the maximum absolute floor acceleration, which is the critical seismic response affecting seismic resilience. In view of these, a hybrid simplified model based on Timoshenko beam (referred to as "HST model" hereafter) was recommended and validated to be capable of predicting the abovementioned critical design index and seismic response. Based on this model, the seismic resilience improvement using seismic isolation was analyzed for an existing RC frame structure. Subsequently, the corresponding results were used to guide the detailed design of seismic isolation scheme. The results indicate that HST model can well predict the critical design index and seismic response. Furthermore, the relative errors of resilient performances predicted by the refined model and HST model are less than 4.5%. In contrast, relative errors are as large as 177% and 31.5% for the repair cost and repair time predicted by HSS model, respectively. The research outcome proves that the recommended model (i.e. HST model) can be used for analyzing the seismic resilience improvement based on seismic isolation. © 2019, Engineering Mechanics Press. All right reserved.