A seismic resilient design method for structures equipped with two-level yielding dampers, accounting for extremely rare earthquakes

Abstract

Current design methods for achieving seismic resilience of structures are limited to hazard levels of service level earthquake, design-based earthquake and maximum considered earthquake, but they do not account for the risk of extremely rare earthquake (ERE) that poses a significant challenge to structural and human safety. To address this issue, this paper proposes a new seismic resilient design method that considers ERE by incorporating two-level yielding dampers as the primary structural fuse while satisfying the performance objectives of all four seismic hazard levels. The paper presents a detailed derivation of the proposed design method and outlines a step-by-step design procedure. The proposed design method is applied to a seismic resilient system called the two-level yielding beam linked steel frame system (TYBLSFS), and two TYBLSFSs with three and six stories are designed and numerically modeled. Nonlinear dynamic analyses are then conducted to validate the effectiveness of the proposed design method. The results show that the two TYBLSFSs achieve the designed targets of roof drift ratio (RDR) and inter-story drift ratio (ISDR) and that the RDR-base shear curves obtained from the dynamic analyses match the design curves. The predetermined yielding mechanism and anticipated performance goals for all four seismic levels have been achieved. And the presented TYBLSFS can be effectively utilized as a seismic resilient system against very strong earthquakes.