HUANG Xiao,HU Zhixiang,LIU Yunlin.Seismic Response Behavior of LRB Base⁃isolated Structure under Extreme Rare Earthquakes[J].Journal of Disaster Prevention and Mitigation Engineering,2022,42(03):436-444.
The LRB (lead-core rubber isolation support) base-isolated structures with three, five, seven and nine-story superstructure were taken as research object. The influence of yield strength ratio, stiffness and hardening coefficient of the superstructure was considered. Through a large number of elastoplastic time history analysis, the nonlinear response characteristics of LRB base-isolated structures without collision or impacting with the moat wall under extremely rare earthquakes were obtained. The results show that increasing the yield strength ratio can effectively reduce the inter-storey displacement and ductility demand of the superstructure. When the yield strength ratio is smaller and the stiffness of the superstructure is larger, the effect of the hardening coefficient on the structural response is greater. When there is no collision, for the LRB base-isolated structures whose self-vibration period of the superstructure changes within a certain range, the ductility demand and the damage state remain unchanged under the determined yield strength ratio. . However, when the LRB layer impacts with the moat wall, the superstructure damage will be very different. Especially, if the superstructure stiffness is large, the ductility demand increases very obviously. In such a case, the superstructure damage has been very serious or even leads to collapse.
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