主余震作用下RC框架-剪力墙结构的多元概率地震需求分析

After a strong earthquake, when the structures damaged by the main earthquake have not been repaired, aftershocks often pose greater threats to the safety of buildings and people. However, the current research in the earthquake engineering community mostly focuses on the effects of main-shocks, and lacks of understanding of the effects of aftershocks. In this paper, the reinforced concrete frame-shear wall structure was taken as the research object, and the finite element modeling was carried out by OpenSees. The finite element model used the SFI-MVLLEM elements and the beam elements with plastic hinges. Multi-variate seismic demand analysis under mainshock-aftershock sequences was carried out by a stepwise multiple strip analysis (SMSA) method. A multiple regression analysis was used to establish the model of the probabilistic seismic demand of the structure under the action of the mainshock-aftershock sequences. Based on this, the concept of the mainshock-aftershock influence coefficient was proposed, and the adverse effects of the mainshock-aftershock sequences on seismic response of the structure were quantitatively investigated. The analysis shows that the effect of mainshock-aftershock sequences on the structure is mainly reflected when the difference between the main shock and the aftershock is small, whereas this effect increases first and then decreases as the earthquake intensity increases. The seismic demand of the structure under the action of the mainshock-aftershock sequences may be increased by about 30%.