基于变形机动分析的薄壁箱梁畸变效应研究  

Research on Distortion Effect of Thin-walled Box Girders Based on Deformation Kinematical Analysis

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,甘肃兰州730070

出　　处：《铁道学报》2024年第6期173-180,共8页Journal of the China Railway Society

基　　金：国家自然科学基金(51968040)。

摘　　要：提出一种通过角点位移分析箱梁畸变效应的理论解析法。基于变形机动分析,以分解的角点位移描述和分析箱梁畸变行为;根据应变假设和闭合箱室满足的翘曲位移连续性条件推导畸变翘曲位移及应力分布模式;根据势能驻值原理,建立以角点位移为未知量的畸变控制微分方程。通过数值算例,验证解析理论和计算方法的正确性。结果表明:按翘曲模式分析的截面翘曲位移沿板宽按直线分布,翘曲正应力的分布与在板元弯曲假设下的应力分布规律相同;考虑泊松比影响后的横向弯矩相比于忽略泊松比时增大未超过0.6%;角点沿垂直顶(底)板方向的畸变位移大于其沿垂直腹板方向的位移分量;腹板与顶板交点处的翘曲正应力和横向弯矩小于腹板与底板交点处的相应值;腹板倾角变化对翘曲正应力和横向弯矩有显著影响,合理减小腹板倾角可一定程度减小翘曲正应力和横向弯矩。A theoretical analytical method was proposed to analyze the distortion effect of box girder by the corner point displacement.Drawing on the deformation kinematical analysis,the box girder deformation behavior was described and analyzed by the decomposed corner point displacements.The distribution modes of distortional warping displacement and stress ware derived using the strain assumption and the warping displacement continuity condition satisfied by the closed section.Based on the stationary principle of potential energy,the distortion governing differential equation was established with the corner point displacement as the unknown quantity.The correctness of the analytical theory and calculation method was proved by numerical examples.The results show that the warping displacement analyzed by the distortion warping mode is linearly distributed along the plate width on the cross section.The distribution of warping normal stress is consistent with that obtained under the assumption of plate bending.Compared with ignoring Poisson’s ratio,the increase of transverse bending moment after considering the influence of Poisson’s ratio does not exceed 0.6%.The displacement of corner point in the direction of vertical top(bottom)plate is greater than that in the direction of vertical web plate.The warping normal stress and transverse bending moment at the intersection of web and top plate are less than the corresponding values at the intersection of web and bottom plate.The change of the web inclination angle has a significant impact on the warping normal stress and transverse bending moment.Reasonably reducing the inclination angle of the web can reduce the warping normal stress and transverse bending moment to a certain degree.

关 键 词：薄壁箱梁 畸变效应 变形机动分析 角点位移 势能驻值原理 

分 类 号：U448.213[建筑科学—桥梁与隧道工程]