摘要
受复杂的地形地貌影响,具有不同墩高的非规则桥梁的抗震性能受支座参数的影响较大。以下部结构为双柱式排架墩的中等跨径连续梁桥为研究对象,通过设置不同墩高组合构造了4类具有不同外形特征的规则和非规则桥梁,保持支座屈服前刚度和屈服后刚度之比不变,改变支座屈服强度和屈服前刚度建立了160个不同隔震参数的连续梁桥,基于OpenSees地震分析平台建立隔震桥梁动力分析模型,通过大量的非线性动力时程分析探讨了规则和非规则桥梁在不同隔震参数下支座剪应变、桥墩位移延性系数、弯矩及剪力需求。结果表明:墩高不一致的非规则桥梁各墩剪力和弯矩需求差异显著大于规则桥梁,一定墩高变化范围下的非规则桥梁桥墩弯矩最大值与最小值的比值约为规则桥梁的2倍,剪力比值约为1.1倍;墩高差异越大,非规则桥梁支座与桥墩的地震响应对隔震参数越敏感;合理设置铅芯橡胶支座(Lead Rubber Bearing, LRB)屈服强度和屈服前刚度是改善非规则桥梁抗震性能的有效途径,当非规则桥梁支座与桥墩屈服强度的比值、屈服前刚度的比值与桥梁等效周期1.5 s时对应的最大刚度的比值之比均为40%~50%时可以在充分发挥支座抗震性能、保护桥墩安全的同时优化其结构受力;研究成果可为LRB隔震桥梁的设计和性能评估提供参考。
Due to the complex terrain and landform,the seismic performance of irregular bridges with different pier heights is strongly influenced by bearing parameters.This study focused on a mediumspan continuous girder bridge with double-column bent piers as substructures.Four types of regular and irregular bridges with different geometric characteristics were constructed by setting different pier height combinations.A total of 160 continuous girder bridges with different isolation parameters were established by changing the yield strength and pre-yield stiffness of the lead rubber bearings(LRBs),while keeping the ratios of pre-yield stiffness and post-yield stiffness unchanged.Then,nonlinear dynamic analysis models of the bridges were established using the OpenSees earthquake analysis platform.Through extensive nonlinear dynamic time history analysis,the shear strain of the bearings,displacement ductility coefficient of the bridge piers,and the bending moment and shear demand of both regular and irregular bridges under different seismic isolation parameters were investigated.The results showed that the differences in shear and bending moment demands among piers in irregular bridges with inconsistent pier heights were significantly greater than those in regular bridges.Within a certain range of pier height variation,the ratio of maximum to minimum bending moments in irregular bridges was approximately twice that in regular bridges,and the shear ratio was about 1.1 times that in regular bridges.The greater the difference in pier heights,the more sensitive the seismic response of the bearings and piers in irregular bridges became to isolation parameters.Proper selection of the yield strength and pre-yield stiffness of LRBs was an effective way to improve the seismic performance of irregular bridges.When the ratio of bearing-to-pier yield strength,as well as the ratio of bearing-to-pier pre-yield stiffness to the maximum stiffness corresponding to the bridge's equivalent period of 1.5s were in the range of 40%~50%,the structural force could be optimized while fully utilizing the seismic performance of the bearings and ensuring pier safety.The findings can provide references for both the design and performance evaluation of bridges with LRB seismic isolation.
作者
秦洪果
王学鑫
石岩
刘云帅
熊利军
QIN Hongguo;WANG Xuexin;SHI Yan;LIU Yunshuai;XIONG Lijun(School of Environment and Urban Construction,Lanzhou City University,Lanzhou 730070,China;School of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,China)
出处
《防灾减灾工程学报》
北大核心
2025年第4期807-818,共12页
Journal of Disaster Prevention and Mitigation Engineering
基金
国家自然科学基金项目(52468071,52268075)
甘肃省教育厅青年博士项目(2023QB-031)
兰州城市学院博士科研基金项目(LZCU-BS2023-26)资助。
关键词
桥梁工程
非规则桥梁
铅芯橡胶支座
非线性时程分析
隔震参数
bridge engineering
irregular bridges
lead rubber bearing
nonlinear time history analysis
seismic isolation parameters
