超高桥塔结构偏心距增大系数计算方法  

Methods to Compute Eccenticity Modifying Factor of High-Rise Bridge Tower

作　　者：苑仁安[1] 傅战工[1] 郑清刚[1] 许磊平[1] 马润平[1] YUAN Ren-an;FU Zhan-gong;ZHENG Qing-gang;XU Lei-ping;MA Run-ping(China Railway Major Bridge Reconnaissance&Design Institute Co.,Ltd.,Wuhan 430056,China)

机构地区：[1]中铁大桥勘测设计院集团有限公司,湖北武汉430056

出　　处：《桥梁建设》2021年第5期37-43,共7页Bridge Construction

基　　金：中国中铁股份有限公司科技研究开发计划项目(2019-重点-07,2020-重点-10)。

摘　　要：针对采用既有规范经验公式计算超高桥塔偏心距增大系数过于保守的问题,对超高桥塔偏心距增大系数的合理计算方法进行研究。基于稳定屈曲理论,推导基于铰接杆、悬臂杆偏心距增大系数的解析表达式;结合桥塔力学行为和偏心距影响系数α,提出更适用于超高桥塔结构的公式算法。依据桥塔的弹性屈曲模态和施工控制精度,构建了桥塔各节点初始缺陷坐标函数,提出了考虑初始缺陷的偏心距增大系数有限元计算方法。以常泰长江大桥为例,对比有限元算法、所提出的公式算法和规范算法下的偏心距增大系数,结果表明:几何非线性效应是偏心距增大系数的主要影响因素;规范算法数值偏大,过于保守;所提出的公式算法与有限元算法吻合度较高,可用于超高桥塔的设计。The eccentricity modifying factor computed using the empirical equations given in the existing codes is considered over conservative.The rational methods to compute the eccentricity modifying factor of high-rise bridge tower are studied.Based on the stable buckling theory,the analytical expression equations are derived premised on the eccentricity modifying factors of articulated rod and cantilever rod.Considering the mechanical property and eccentricity influencial coefficientαof the tower,equations more suitable for the high-rise tower are proposed.In accordance with the elastic buckling mode of the tower and the construction control accuracy,the coordinates functions of initial defects of each node of the tower is worked out,and a finite element method to compute the eccentricity modifying factor is presented,taking into consideration the initial defects.As an example of the Changtai Changjiang River Bridge,the eccentricity modifying factors gained by the finite element method,the proposed equations and empirical equations in the codes were compared.The results show that geometric nonlinear effect is directly related to the eccentricity modifying factor.The empirical eqations in the codes give rise to bigger computing results,which is over conservative.While the results computed by the proposed equations agree well with the results computed by the finite element method,which can be used in the design of the high-rise tower.

关 键 词：超大跨度桥梁 超高桥塔结构 偏心距增大系数 稳定屈曲 初始缺陷 公式算法 有限元法 

分 类 号：U443.38[建筑科学—桥梁与隧道工程] U441[交通运输工程—道路与铁道工程]