横梁屈服对斜拉桥横向地震反应的影响  

Influence of Crossbeam Yielding on Transverse Seismic Response of Cable-Supported Bridge

作　　者：夏修身[1,2] 李建中[1] 徐艳[1] 嵇冬冰[1] 

机构地区：[1]同济大学土木工程学院,上海200092 [2]兰州交通大学土木工程学院,甘肃兰州730070

出　　处：《华南理工大学学报（自然科学版）》2014年第5期84-89,共6页Journal of South China University of Technology(Natural Science Edition)

基　　金：国家"973"计划项目(2013CB036302);国家自然科学基金资助项目(51278371;51368033)

摘　　要：未来地震的强度具有不确定性,在超设防地震下,斜拉桥的桥塔横桥向有可能进入非线性状态.基于某大跨度斜拉桥,文中建立了空间有限元模型,分析了强震下横桥向的地震反应,引入能力与需求之比来判断横梁是否进入屈服状态.同时,采用纤维梁单元模型模拟横梁的非弹性行为,重点研究了横梁屈服对斜拉桥横桥向整体抗震性能的影响.结果表明:斜拉桥横梁的能力与需求之比较小,将其按延性抗震设计比较合理;横梁的地震轴力变化较大,对横梁的屈服弯矩有较大的影响;横梁屈服后对斜拉桥的横向地震反应有较大的影响,可能会增大塔底弯矩,设计中需要考虑.The intensity of future earthquake is unpredictable. The tower in transverse direction of cable-stayed bridge may act in a nonlinear way in ultra-fortified earthquakes. In this paper, by taking a long-span cable-stayed bridge as the research object, a finite element model is established to analyze the transverse seismic response of cable-stayed bridge under the action of strong earthquake. Then, the seismic capacity-to-demand ratio is introduced to judge whether the crossbeam is yielding. Moreover, a fiber section beam element is employed to simulate the ine- lastic behavior of crossbeam, and the influence of crossbeam yielding on the transverse seismic response of cable- stayed bridge is finally investigated in detail. The results show that （1） as the seismic capacity-to-demand ratio of cable-stayed bridge crossbeam is relatively small, a ductility design for crossbeam may be more reasonable; （2） the seismic axial force of crossbeam changes significantly, which may greatly affect the yielding moment ; and （3） as the yielded crossbeam greatly affects the transverse seismic response of cable-stayed bridge, the increasing bending moment of tower base should be considered in the design process.

关 键 词：斜拉桥 横梁 地震反应 纤维截面梁单元 

分 类 号：U442.55[建筑科学—桥梁与隧道工程]