碰撞对山区高墩桥弹塑性动力响应的影响  

Effect of Pounding on Elastic-Plastic Dynamic Response of High Pier Bridge in Mountainous Area

作　　者：李晰[1,2] 贾宏宇[1,2] 李倩[1] 康锐[1,2] 陈志伟[1] 

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]西南交通大学高速铁路线路工程教育部重点实验室,四川成都610031

出　　处：《西南交通大学学报》2018年第1期109-118,共10页Journal of Southwest Jiaotong University

基　　金：国家自然科学基金资助项目(1508473,51308465)

摘　　要：为了研究碰撞对山区高墩桥动力响应的影响,以某一大跨度高墩桥体系为原型,充分考虑了碰撞过程中的刚度变化、能量耗散以及桥墩的非线性行为,基于Open Sess平台建立了两种典型桥跨结构的弹塑性动力分析模型.在此基础上,利用所选的天然地震波和人工地震波对比分析了碰撞效应对山区高墩桥弹塑性动力响应的影响.研究结果表明:碰撞会对高墩桥结构的动力响应产生较为明显的影响,特别是场地条件较差时,其最大改变率为15.86%,桥墩与主梁的连接方式会进一步改变碰撞对桥墩变形的影响程度;相邻结构动力特性差异越大,高墩桥体系发生碰撞的概率就越大,但碰撞次数的增加可能会对桥墩变形起到限制作用,降低桥墩的响应,在确定山区高墩桥体系相邻结构周期比时,既要考虑相邻结构动力特性差异对碰撞概率的影响,还应考虑其对碰撞效应的影响;高墩桥的梁-桥台碰撞主要受地震动作用大小的影响,地震动的强度和相邻结构动力特性的差异均会对梁-梁碰撞产生影响,在对高墩桥进行减撞防撞设计时,应针对不同的碰撞位置采取不同的措施.To s tudy the effect of pounding on the seismic re sponse of high-pier br idge in mountainous areas,the elast ic-plast ic dynamic analysis models of two typical br idge structures were establ ished by using the OpenSees framework, b a sed on th e prototype of a re a l h ig h -p ie r b r id g e . The va ria tion in stiffness,energy dis s ipa t ion dur ing the pounding process, and the non- l inear behavior of the piers were fully considered in the models. Additionally,th e effect of p o u n d in g on dyn amic re sp o n se s of a high- pier bridge was analyzed by using the selected natural and artificial ground motions. The results show that pounding can significantly affect the structural responses, e sp e c ia l ly for poo r si te c o n d i t io n s, an d the maximum change rate is 15. 86% . Moreover, the method of connecting the pier and beam further influences the effect of pounding on the pier displacement; A larger difference in dynamic characteristics of adjacent structures corresponds to a larger probability of collision; however, the increasing frequency of pounding may reduce the responses of piers,owing to th e res tr ic t io n effect onthe pier deformation. Thus, when selecting the period ratio of adjacent structures, it is necessary to consider its effect on not only the probability of pounding, but also on the degree of effect of pounding. In comparison, beam-abutment pounding is mainly affected by the intensity of ground motions, whereas the beam-beam pounding is influenced by both the intensity of ground motions and the difference in dynamic characteristics of adjacent structures. Therefore, in seismic design, to reduce the pounding of high-pier bridges, it is suggested that different measures should be adopted for different pounding positions.

关 键 词：桥梁工程 高墩桥 弹塑性分析 碰撞 场地条件 

分 类 号：U442.55[建筑科学—桥梁与隧道工程]