新型铁路桥墩的抗震性能研究  

Study of Seismic Performance of a New Type of Railway Bridge Pier

作　　者：夏修身[1] 陈兴冲[1] 艾宗良[2] 

机构地区：[1]兰州交通大学土木工程学院,甘肃兰州730070 [2]中铁二院工程集团有限责任公司,四川成都610031

出　　处：《桥梁建设》2017年第5期12-17,共6页Bridge Construction

基　　金：国家自然科学基金项目(51368033;51668035);中国铁路总公司科技研究开发计划课题(2015G002-B)~~

摘　　要：针对铁路桥梁摇摆隔震桥墩整体侧向刚度较低的问题,提出在桥墩与承台分离处设置无粘结预应力筋,形成新型桥墩。以某单线铁路桥为例,针对其18号墩提出新型桥墩设计方案,考虑预应力钢筋及其初始预加力损失,基于OpenSees平台建立有限元模型进行地震反应分析,研究其抗震性能。结果表明:罕遇地震作用下,墩顶水平位移、竖向提离位移、墩底弯矩、摇摆反应及预加力损失明显大于设计地震作用下的相应值,但墩底弯矩的增幅小于墩顶水平位移的增幅;输入地震动强度及频谱特性对墩顶位移与墩底提离位移的影响较大,对墩底弯矩的影响相对较小;新型桥墩容易实现罕遇地震作用下不坏的抗震设防要求,具有较好的抗震性能。In view of the problem of the low global lateral stiffness of the rocking piers of railway bridges,a new type of the bridge pier that was to be formed by arranging the unbonded prestressing tendon at the separation of the pier and pile cap was proposed.By way of example of a single-track railway bridge,the design scheme of the new pier for the existing pier No.18 of the bridge was developed and in consideration of the prestressing tendon itself and its initial pre-applied force loss,the finite element model for the new pier was established on the OpenSees platform,the seismic responses of the pier were analyzed and the seismic performance was studied.The results of the analysis and study demonstrate that under the action of the rare earthquake,the values of the pier top horizontal displacement,vertical uplift displacement,pier footing bending moment,rocking responses and the pre-applied force loss are all significantly greater than the corresponding values under the action of the designed earthquake,however,the increase of the pier footing bending moment is less than that of the pier top horizontal displacement.The influences of the intensity and frequency spectrum characteristics of the input ground motion on the pier top horizontal displacement and the vertical uplift displacement are great while on the pier footing bending moment are relatively little.The new pier can easily fulfill the seismic fortification requirement that the pier will not be damaged under the action of the rare earthquake and the pier therefore has rather good seismic performance.

关 键 词：铁路桥 桥墩 抗震性能 桥墩承台分离 无粘结预应力钢筋 预加力 有限元法 

分 类 号：U448.13[建筑科学—桥梁与隧道工程] U443.22[交通运输工程—道路与铁道工程]