铁路高低塔混合梁斜拉桥约束体系设计  

Design of Restraint System for a Hybrid Girder Railway Bridge with Two Pylons of Different Heights

作　　者：李方柯 LI Fangke(China Railway Fifth Survey and Design Institute Group Co.,Ltd.,Beijing 102600,China)

机构地区：[1]中铁第五勘察设计院集团有限公司,北京102600

出　　处：《世界桥梁》2024年第1期25-31,共7页World Bridges

基　　金：蜀道投资集团有限责任公司科技计划项目(SRIG2020GG0001);中铁第五勘察设计院集团有限公司科技研发课题(T5Y2020-B03)。

摘　　要：汉巴南铁路嘉陵江大桥主桥采用(45+55+58+335+58+49)m高低塔混合梁斜拉桥,以降低结构内力和位移响应、优化行车条件及轨道结构使用性能为目标,对大桥的约束体系进行设计。选取3种纵向约束、5种横向约束体系方案,建立有限元模型分析各方案静力及地震作用下的结构响应,得到纵向采用阻尼约束或支座位移约束的半飘浮体系时结构静力响应差异较小,采用阻尼约束时的地震响应较小,横向采用阻尼约束或挡块限位约束均能实现较好的耗能限位效果,采用阻尼约束时的减震效率不高。根据各方案地震响应结果,结合行车条件及轨道结构的性能需求,该桥纵向采用组合式约束体系,运营及设计地震作用下为带支座纵向位移约束的半飘浮体系,罕遇地震作用下为带纵向阻尼约束的半飘浮体系;横向采用固定支座+限位挡块的方案;根据约束方案确定了约束布置和相关技术参数,实现了铁路桥梁的性能目标。Featuring two pylons of different heights,the main bridge of a Jialingjiang River Bridge carrying a section of the Hanzhong-Bazhong-Nanchong High-speed Railway is a hybrid girder cable-stayed structure that are arranged in six spans of 45,55,58,335,58,and 49 m.A bespoke restraint system is developed to reduce the internal forces and displacement responses of the structure,as well to optimize the train travelling and rail track service conditions.Three longitudinal restraint systems and five transverse restraint systems were selected,and numerical analysis was carried out to compare the structural responses of the bridge with these restraint systems under static and seismic actions.As per the analysis,for a semi-floating system with a longitudinal damping restraint or with bearing displacement restraint,the static responses of the structure show minor difference and the seismic performance of the structure with damping restraint is better,while adopting the transverse damping restraint or stoppers to prevent girder falloff leads to better energy dissipation and limiting effect,but the damping restraint is not an effective seismic mitigation solution.In accordance with the seismic responses of these solutions as well as the demands on train travelling and rail track service conditions,a combined longitudinal restraint system is presented,with which the bridge remains a semi-floating system with bearing longitudinal displacement restraint at service stage and under the action of design seismic loads,and transform to be a semi-floating system with longitudinal damping restraint under rare earthquakes.The transverse restraint consists of permanent bearings and stoppers.The configuration and technical parameters were calculated to achieve the optimal performance target of the railway bridge.

关 键 词：高速铁路桥 斜拉桥 高低塔 混合梁 约束体系 桥梁设计 

分 类 号：U448.27[建筑科学—桥梁与隧道工程] U442.5[交通运输工程—道路与铁道工程]