双线混凝土U型梁的剪力滞效应研究  

Study on shear lag effect of double-line concrete U-girders

作　　者：王旭飞 赵亚宁 冀伟[1,2] WANG Xufei;ZHAO Yaning;JI Wei(Lanzhou Jiaotong University,Lanzhou 730070,China;China Railway 18th Bureau Group Co.,Ltd.,Tianjin 300222,China)

机构地区：[1]兰州交通大学,甘肃兰州730070 [2]中铁十八局集团有限公司,天津300222

出　　处：《铁道科学与工程学报》2022年第1期181-190,共10页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(51708269);甘肃省科技重点研发计划项目(20YF3FA03);天津市科技计划项目(18ZXGDGX00050);兰州市人才创新创业项目(2021-RC-39)。

摘　　要：为了研究双线混凝土U型梁的剪力滞效应,对U型梁截面进过合理简化,选取轴力自平衡的余弦函数定义了翘曲位移函数。在考虑剪滞效应和剪切效应的基础上,构建了双线混凝土U型梁的总应变能函数。利用势能驻值原理,推导出了简支、悬臂和连续双线混凝土U型梁分别在均布荷载和集中荷载作用下的剪力滞系数解析解。以某实际工程双线混凝土U型梁为例,对解析法和有限元模型计算得到的剪力滞系数进行对比分析。计算双线混凝土U型梁道床板的有效分布宽度,并基于有限元模型的计算结果,对理论解的有效分布宽度进行系数修正。研究结果表明:剪力滞系数的理论计算结果与有限元模型计算结果的最大偏差不超过±10%,表明所推导解析解的精度较高;双线混凝土U型梁在均布荷载和集中荷载作用下,跨中截面的剪力滞变化规律相同,均在主梁和道床板交界处剪力滞系数最大,随离交界处距离的增大而减小;相比均布荷载作用,集中荷载作用下的剪力滞效应更明显,需在实际工程中重点考虑;在双线混凝土U型梁道床板有效分布宽度的计算中,引入修正系数1.05对解析计算结果加以修正,以得到更精确的结果。基于理论推导所得的双线混凝土U型梁剪力滞效应变化规律,以及对道床板有效分布宽度提出的修正系数,可为同类型桥梁的设计计算提供参考依据。To study the shear lag effect of the double-line concrete U-shaped girder,the section was simplified reasonably and warping displacement function was defined by selecting the cosine function of self-balancing axial force.On the basis of considering the shear lag effect and the shear deformation,the total strain energy function of the double-line concrete U-shaped girder was plotted.Using the displacement variational principle,the analytical solutions about the shear lag coefficients of simply supported,cantilevered and continuous the double-line concrete U-shaped girder under uniformly distributed and concentrated loads were deduced separately.Taking an actual project as an example,the shear lag effect calculated by the analytical theory method and the finite element model were compared and analyzed,and the effective distribution width of double-line concrete U-shaped girder bed slab was also calculated.Then,based on the calculation results of the finite element model,the effective distribution width coefficient of the theoretical solution was corrected.The research results show that the maximum deviation of the shear lag coefficient between the theoretical calculation result and finite element calculation results does not exceed±10%,which shows that the analytical solution has high accuracy and reliability.The shear lag effect change law of the double-line concrete U-shaped girder at the mid-span section is the same under uniform load and concentrated load.The shear lag coefficient decreases with the increase of the distance from the junction,and is the largest at the junction of the main girder and the track bed slab.Compared with the uniformly distributed load on the full span,the shear lag effect under the concentrated load is more obvious,which needs to be considered emphatically in the actual project.In the calculation of the effective distribution width of the double-line concrete U-shaped girder bed slab,a correction coefficient of 1.05 is introduced to modify the theoretical calculation results,and more

关 键 词：U型梁 势能驻值原理 剪力滞效应 有限元 有效分布宽度 

分 类 号：U24[交通运输工程—道路与铁道工程]