考虑LRB环境温度效应及铅芯发热的隔震斜交桥近断层地震反应分析  

Analysis on the seismic responses of isolated skew bridges considering the ambient temperature effect and lead core heating of LRB under near-fault ground motions

作　　者：张展宏 石岩[2] 秦洪果 ZHANG Zhanhong;SHI Yan;QIN Hongguo(Institute for Disaster Management and Reconstruction,Sichuan University,Chengdu 610207,China;School of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]四川大学灾后重建与管理学院,成都610207 [2]兰州理工大学土木工程学院,兰州730050

出　　处：《振动与冲击》2022年第14期172-180,共9页Journal of Vibration and Shock

基　　金：国家自然科学基金(51908265)。

摘　　要：低温环境和铅芯发热会引起铅芯橡胶支座(lead rubber bearing,LRB)力学特性的变化。为探讨其对支座力学性能的影响,从铅和橡胶材料特性层面对支座力学性能进行修正,以考虑低温对支座力学特性的影响;采用强度退化力学模型考虑LRB往复运动时内部铅芯发热对其力学特性的影响。基于OpenSees地震分析平台建立动力分析模型,研究在近断层地震动作用下隔震斜交桥地震反应与环境温度、铅芯发热及斜度的关系。研究表明:低温环境会使梁体旋转度和支座的位移响应明显减小,桥墩的地震反应显著增大,铅芯发热对桥墩和支座地震反应影响较小;当环境温度和铅芯发热共同作用时,桥墩纵、横向墩底剪力和扭矩都被显著放大,低温环境对其地震反应起主导作用;在同一低温下,桥墩纵向墩底剪力和扭矩的放大程度随着斜度的增大而逐渐增大,在-30℃低温下,斜度为60°斜交桥桥墩的纵向剪力和扭矩分别被放大20%和39%。Low temperature environment and lead core heating can cause the change of mechanical properties of lead rubber bearings(LRBs).The performance of the bearing was modified from the aspect of lead and rubber material characteristics and then,the influence of low temperature on the mechanical properties of the bearing was considered.A strength degradation model was used to consider the influence of lead core heating on the mechanical properties of the bearing.Based on the OpenSees seismic analysis platform,a dynamic analysis model was established to study the relationships between the seismic response and the ambient temperature,lead core heating and skew under near fault ground motions.The results show that the rotation of the beam body and the displacement of the bearing are significantly reduced under low temperature environment,while the seismic responses of piers are significantly increased.The lead core heating has little influence on the seismic responses of piers and bearings.Under the combined action of ambient temperature and lead core heating,the shear force and torque of the piers are significantly amplified,and the low temperature environment plays a leading role in its seismic responses.At the same low temperature,the amplification degrees of longitudinal shear force and torque at the bottom of piers increases with the increase of a skew.At-30℃,the longitudinal shear force and torque of the piers of a skew bridge with the skewness of sixty are amplified by 20%and 39%respectively.

关 键 词：斜交桥 铅芯橡胶支座(LRB) 环境温度 铅芯发热 地震反应 斜度 

分 类 号：U442.55[建筑科学—桥梁与隧道工程]