Fragility analysis and collapse margin capacity assessment of mega-sub controlled structure system under the excitation of mainshock-aftershock sequence

The mega-sub controlled structure system (MSCSS) is a revolutionary type of energy dissipation structure. Its damping performance can be improved further with the addition of dampers, lead rubber bearings (LRB), and other components, but its seismic performance in the mainshockaftershock sequence has yet to be investigated. The incremental dynamic analysis approach is employed in this study to determine the vulnerability of MSCSS during the mainshock-aftershock sequence, as well as its fragility curve. Following that, the effect of aftershock intensity on the structural fragility curve is explored, as well as the possibility of exceeding each limit state for the four structures under the excitation of the mainshock-aftershock sequence from the aspect of failure probability. In addition, the collapse margin ratio (CMR) of four structures is solved, the structural residual collapse margin capacity is investigated, and the structure's seismic reserve capacity is assessed. The findings also demonstrate that putting LRB on the additional column improves the seismic resistance of MSCSS.

Automated summary

This study investigates the vulnerability and fragility curve of the mega-sub controlled structure system (MSCSS) during the mainshock-aftershock sequence using the incremental dynamic analysis approach. The study also explores the effect of aftershock intensity on the structural fragility curve and the possibility of exceeding each limit state. Findings show that adding lead rubber bearings (LRB) to the additional column improves the seismic resistance of MSCSS.