考虑扭转与畸变耦联影响的薄壁箱梁翘曲效应分析  

Analysis on warping effect of thin-walled box girders considering coupling between torsion and distortion

作　　者：张元海[1,2] 马云亮 刘泽翔 Zhang Yuanhai;Ma Yunliang;Liu Zexiang(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China;Key Laboratory of Road&Bridge and Underground Engineering of Gansu Province,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 [2]兰州交通大学甘肃省道路桥梁与地下工程重点实验室,兰州730070

出　　处：《东南大学学报（自然科学版）》2023年第3期418-424,共7页Journal of Southeast University：Natural Science Edition

基　　金：国家自然科学基金资助项目(51968040);兰州交通大学基础研究拔尖人才培养计划资助项目(2022JC17).

摘　　要：为了分析薄壁箱梁在竖向偏载作用下的整体受力性能,考察剪力滞、约束扭转及畸变翘曲应力相对于竖向弯曲应力的放大系数,在充分考虑扭转与畸变耦联影响的基础上,用能量变分法建立了综合反映竖向弯曲变形以及剪力滞、约束扭转、畸变等翘曲变形的控制微分方程.对既有文献中的模型梁及某预应力混凝土简支箱梁在跨中偏载作用下的应力状态进行理论分析.结果表明,按该控制微分方程求得的模型梁应力理论值与实测值吻合良好.跨中截面加载腹板与底板交点处的正应力放大系数达到约1.63,在水平形心轴处腹板的剪应力放大系数达到约2.55.在剪力滞、约束扭转及畸变翘曲应力中,畸变和约束扭转翘曲应力占主导地位,剪力滞翘曲应力占次要地位,但仍不可忽略.To analyze the overall mechanical performance of thin-walled box girders under vertical eccentric loads,and to investigate the amplification coefficients of the warping stresses due to shear lag,restrained torsion,and distortion on vertical bending stress,the governed differential equations comprehensively reflecting vertical bending deformation and warping deformations such as shear lag,restrained torsion,and distortion were established by using the energy variation method on the basis of considering the coupling between torsion and distortion.Theoretical analysis was conducted on the stress statement of the model girder in existing literature and a prestressed concrete simply supported box girder subjected to mid-span eccentric load.The results show that the theoretical values of the stress of the model girder obtained by the governed differential equations are in good agreement with the measured values.The amplification coefficient for the normal stress at the intersection between the mid-span loaded web and the bottom plate reaches about 1.63,and that for the shear stress at the intersection between the horizontal centroid axis and the web reaches about 2.55.Among the warping stresses due to shear lag,restrained torsion,and distortion,the warping stresses due to distortion and restrained torsion dominate,followed by that due to shear lag,but it cannot yet be ignored.

关 键 词：薄壁箱梁 畸变 约束扭转 剪力滞 翘曲应力 

分 类 号：U448.213[建筑科学—桥梁与隧道工程]