考虑畸变与扭转耦合变形的箱梁偏载效应分析  

Analysis of the Eccentric Load Effect of Box Girders Considering Coupling Deformation of Distortion and Torsion

作　　者：刘泽翔 张元海[1] LIU Zexiang;ZHANG Yuanhai(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China)

机构地区：[1]兰州交通大学土木工程学院,兰州730070

出　　处：《兰州交通大学学报》2025年第1期114-120,共7页Journal of Lanzhou Jiaotong University

基　　金：国家自然科学基金(52368020);甘肃省优秀研究生“创新之星”项目(2022CXZX-527)。

摘　　要：为全面分析偏载对薄壁箱梁的应力放大效应,给出一种考虑畸变及其与扭转耦合变形的应力放大系数计算方法。基于广义坐标法的变形假设,根据虚位移原理推导复合变形控制微分方程组,给出变形状态向量的初参数解与应力放大系数计算式。采用简支钢箱梁算例验证理论方法的正确性。结果表明:简支钢箱梁承受车道偏载时,顶板正应力和腹板剪应力的应力放大系数沿纵向从支座到跨中先衰减后增大,扭转、畸变耦合变形应力对弯曲应力的放大效应在跨中最明显,跨中腹板中点的剪应力放大系数为2.00。顶板翘曲正应力对弯曲正应力的放大效应与该点至顶板中点的距离正相关。薄壁箱梁的偏载效应分析应考虑畸变的应力放大效应也不可忽视其与扭转的耦合影响。In order to comprehensively analyze the stress amplification effect of eccentric load on thin walled box girders,a calculation method of stress amplification coefficients considering distortion and the coupling deformation of distortion and torsion was proposed.Based on the deformation assumption of generalized coordinate method and the principle of virtual displacement,the governed differential equations of composite deformation were derived.The initial parameter solution of the deformation state vector and the calculation formulas of stress amplification coefficients were given.The correctness of the theoretical method was verified using the example of a simply supported steel box girder.The result shows that when the simply supported steel box girder is subjected to an eccentric lane load,the normal stress amplification coefficient of the top plate and the shear stress amplification coefficient of the web first reduce and then increase along the longitudinal direction from the support to the mid span.The amplification effect of the coupled deformation stress generated by the coupling between torsion and distortion on the bending stress is most pronounced in the mid span.In the mid span,the amplification coefficient of shear stress at the midpoint of the web is 2.00.On the top plate,the amplification effect of the warping normal stress on the bending normal stress is positively correlated with the distance from the calculated point to the midpoint of the top plate.The eccentric load effect analysis of thin walled box girders should consider the stress amplification effect of distortion and the coupling effect of distortion and torsion cannot yet be ignored.

关 键 词：薄壁箱梁 广义坐标法 初参数解 偏载效应 应力放大系数 

分 类 号：U448.213[建筑科学—桥梁与隧道工程]