Abstract：Lead-rubber bearings (LRBs) are extensively used seismic isolators in bridges.The cyclic deformation of LRBs under earthquake can cause heating accumulation and temperature rising.As a result, variations of mechanical properties of LRBs including dropping of hysteretic energy dissipation, characteristic strength and stiffness threaten seismic safety of bridges.Here, according to the code of the lead rubber bearing isolator for highway bridge (JT/T 822—2011), 22 types circular LRBs were taken as objects to establish 40 single bearing isolation structure models with different periods.40 bilateral near-fault ground motion records suitable to transportation field structure aseismic design were input into models to perform nonlinear dynamic time history analyses.Effects of lead core heating on LRBs’ displacement, temperature, characteristic strength and hysteretic energy dissipation were studied.In addition, relations among increment of lead core temperature, characteristic strength reduction rate and near-fault ground motion were discussed to establish fitted relation expressions among bearing displacement ductility coefficient, shear strain and Qd/W.Results showed that for the isolated systems with medium-long periods (1.5~3 s) under near fault ground motion, lead core temperature rising and characteristic strength dropping are obvious, the increase in lead core temperature is 50 ℃-80 ℃, characteristic strength drops 20%-40%; displacement responses of LRBs can be under-estimated by 15% not considering lead core heating.
石岩，王浩浩，秦洪果，韩建平，熊利军. 近断层地震动下公路桥梁铅芯橡胶支座变形发热及性能退化效应研究[J]. 振动与冲击, 2020, 39(23): 96-106.
SHI Yan, WANG Haohao, QIN Hongguo, HAN Jianping, XIONG Lijun. Deformation, heating and performance degradation of lead rubber bearings for highway bridges under near fault ground motions. JOURNAL OF VIBRATION AND SHOCK, 2020, 39(23): 96-106.
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