大跨连续刚构桥桥墩计算长度系数的取值研究  

Value of Effective Length Coefficient of Pier of Long-Span Continuous Rigid Frame Bridge

作　　者：唐利科 宋随弟[1] 张扬 TANG Like;SONG Suidi;ZHANG Yang(China Railway Eryuan Engineering Group Co.,Ltd.,Chengdu,Sichuan 610031,China)

机构地区：[1]中铁二院工程集团有限责任公司,四川成都610031

出　　处：《中外公路》2024年第4期190-196,共7页Journal of China & Foreign Highway

摘　　要：桥墩计算长度系数是影响桥梁结构安全与经济性指标的一个控制性因素,国内外规范关于受压杆件计算长度系数的取值相近,且都仅是针对理想边界条件的情况,在实际应用中有必要根据具体的结构形式作适当调整。为得到更接近结构实际情况的数值,该文从结构整体稳定分析入手,分析不同因素对连续刚构桥成桥及最大双悬臂阶段计算长度系数的影响规律,主要包括不同桥墩类型、墩身高度、桩基柔度、邻跨边界、单墩失稳或者整体失稳等。结果表明:不同桥墩类型顺、横向的计算长度系数不能简单地采用某一固定值,随墩高的变化也不是简单的线性关系;考虑桩基柔度影响后的结果会增大20%左右,且横桥向比顺桥向的影响更加显著;考虑交接墩影响后计算长度系数的取值更大;需要考虑各墩同时受轴向荷载作用下的整体屈曲反应;连续刚构施工阶段最大双悬臂工况下顺桥向计算长度系数分布范围为1.20~1.35。The effective length coefficient of a pier is a controlling factor affecting the safety and economic index of bridge structures.The values of the effective length coefficient of compression members in Chinese and foreign codes are basically similar,and they are only applicable to ideal boundary conditions.In practical application,it is necessary to make appropriate adjustments according to the specific structural form.In order to get the value closer to the actual situation of the structure,this paper analyzed the overall stability of the structure and investigated the influence laws of different factors on the effective length coefficient of the continuous rigid frame bridge in the completion stage and the maximum double cantilever stage,mainly including different pier types,pier height,pile foundation flexibility,adjacent span boundary,single pier instability,or overall instability.The results show that the effective length coefficient of different pier types along and across the bridge is not a fixed value,and the variation of the effective length coefficient with the pier height is not a simple linear relationship.Due to the influence of pile foundation flexibility,the result will increase by about 20%,and the influence across the bridge direction is more significant than that along the bridge.After considering the influence of connecting piers,the value of the effective length coefficient is larger.It is necessary to consider the overall buckling response of each pier under axial load at the same time.The distribution range of the effective length coefficient along the bridge under the maximum double cantilever condition in the construction stage of a continuous rigid frame is 1.20‒1.35.

关 键 词：连续刚构桥 计算长度系数 临界荷载 压杆 约束 欧拉公式 

分 类 号：U443.22[建筑科学—桥梁与隧道工程]