荷载横向变位下变截面连续箱梁剪滞分析的有限梁段法  

Finite segment method for shear lag analysis of non-uniform continuous box girder with varying lateral loading positions

作　　者：牟兆祥[1] 郭文华[2] 魏诗雅[2] 

机构地区：[1]铁道第三勘察设计院集团有限公司,天津300142 [2]中南大学土木工程学院,长沙410075

出　　处：《应用力学学报》2014年第1期150-155,13,共6页Chinese Journal of Applied Mechanics

基　　金：国家自然科学基金(51078356)

摘　　要：为研究荷载横向作用位置变化对箱梁剪滞效应的影响，对箱梁顶、底板、悬臂板分别设置了不同的剪滞纵向位移差函数；假定纵向翘曲位移沿横向分布为k次抛物线，并考虑剪滞和剪切双重效应的影响，通过能量变分法推导出了荷载横向变位时梁段单元的平衡控制微分方程组及其闭合解；提出了能对工程中常见的变截面连续箱梁剪滞效应进行分析的有限梁段法。该方法计算结果与有限元模型、已有模型试验结果的最大误差在5．95％～9．74％之间，两种工况下计算结果的叠加与有限元结果相对误差在0．07％～19．18％之间，均吻合良好，说明将基于有限梁段法的剪滞效应变分解和叠加原理用于求解复杂力状态下的剪滞效应是可行的。剪滞翘曲位移横向分布函数精度选择的研究结果表明：均布荷载分别作用于腹板顶部、项板中心时，翘曲位移横向分布函数宜分别选用三次、二次抛物线。To investigate the influence of lateral loading position on the shear lag of girders, the wings of box girder are set separately with different longitudinal displacement difference functions, the longitudinal displacements' distribution functions are assumed to take k-th order parabola, both shear lag effect and shear deformation are considered, then the governing differential equations and their solutions are derived with variational method when the loading position varied, the finite segment method was used to solve shear lag effect of non-uniform continuous box girder undergoes uniform load. The results of the presented method are in good agreement with those of the finite element model and model test, the maximum relative errors range from 5.95%to 9.74%,and the relative errors of superimposed results under two different load conditions and Ansys results are between 0.07% and 19.18%.The study shows that variational method and superposition principle are feasible to solve shear lag effect under complex load condition. The study of precision selection of warping displacement function shows that the lateral distribution functions of warping displacement are supposed to select cubic and second order parabolas respectively when the loads act on the web or the top plate.

关 键 词：薄壁箱梁 剪滞效应 剪切变形 荷载横向位置 变分法 有限梁段法 

分 类 号：U448.213[建筑科学—桥梁与隧道工程]