车道荷载作用下的变截面连续箱梁桥约束扭转分析  

Analysis on restrained torsion of continuous box girder bridge with variable section under lane load

作　　者：尉浩浩 张和[1] 何昊 王磊 刘志 WEI Haohao;ZHANG He;HE Hao;WANG Lei;LIU Zhi(Powerchina Northwest Engineering Co.,Ltd.,Xi’an 710065,China;Logistics Infrastructure Department,Lanzhou Vocational Technical College,Lanzhou 730070,China)

机构地区：[1]中国电建集团西北勘测设计研究院有限公司,西安710065 [2]兰州职业技术学院后勤基建处,兰州730070

出　　处：《计算力学学报》2025年第1期139-145,共7页Chinese Journal of Computational Mechanics

基　　金：国家自然科学基金(52468044)资助项目。

摘　　要：为了分析约束扭转效应对箱梁截面应力的影响,基于箱梁约束扭转微分方程初参数解,推导出自由扭矩和二次扭矩的初参数解析式;引入以扭转角和广义翘曲位移为节点位移的箱梁单元,根据乌氏第二理论和箱梁单元推导出单元刚度矩阵、自由扭矩、二次扭矩的计算矩阵和等效节点荷载列阵;利用Fortran语言编写有限元程序,用于分析变截面连续箱梁桥的约束扭转效应,并用程序计算某变截面三跨连续箱梁桥在双力矩最不利布载下的截面内力和位移。结果表明,约束扭转效应引起的二次剪应力与扭转剪应力的比值在腹板上达到峰值,其比值在支点截面和集中荷载作用截面上分别可达到35.66%和68.23%,而在其余截面上未超过2.23%;沿纵桥向,正应力放大系数和剪应力放大系数的峰值出现在支点截面;对于本文实例桥,正应力放大系数的取值范围为1.077~1.304,剪应力放大系数的取值范围为1.822~2.667。In order to analyze the effect of the constrained torsion on the section stress of a box beam,based on the initial parametric solution of the restrained torsion differential equation of the box girder,the initial parametric analysis formula of free and secondary torques is derived.According to Umansky′s Second Theory and the box girder element,the element stiffness matrix,calculation matrix of free torque and secondary torque and the equivalent node load column vector are derived by introducing the box girder element with torsion angle and generalized warping displacement as node displacements.The finite element program coded in Fortran Language is applied to analyze the constrained torsion effect of continuous box girder bridges with variable sections.The program is also used to calculate the internal force and displacement of a three-span continuous box girder bridge with variable sections under the most unfavorable bimoment loading mode.The results show that the ratio of the secondary shear stress to the torsional shear stress caused by the constrained torsion effect reaches its peak on the webs.It reaches 35.66%and 68.23%respectively on the fulcrum section and the concentrated load section while it is not more than 2.23%on the rest of sections.Along the longitudinal bridge,the peak values of the normal stress and shear stress amplification factor appear at the fulcrum section.For the bridge in this paper,the normal stress amplification factor ranges from 1.077 to 1.304 and the shear stress amplification factor from 1.822 to 2.667.

关 键 词：箱梁 约束扭转 单元刚度矩阵 二次剪应力 扭转剪应力 应力放大系数 

分 类 号：U448.213[建筑科学—桥梁与隧道工程] O302[交通运输工程—道路与铁道工程]