中文摘要：

从满足剪力滞翘曲应力的轴向平衡条件出发，选取三次抛物线翘曲位移模式，考虑了悬臂板宽度及上下翼板至形心轴不同距离的影响，从而更合理反映箱形粱剪力滞翘曲应力．导出了剪力滞翘曲惯性矩、惯性积和面积等几何特性计算公式．根据最小势能原理，建立了薄壁箱梁挠曲剪力滞的控制微分方程．采用有限差分法推导出变截面悬臂箱梁剪力滞效应计算式和边界条件．运用Ansys有限元软件中的Shell63单元进行建模，分析单箱双室三跨连续箱梁剪力滞效应的分布规律．对比分析了翘曲位移模式及轴力平衡条件对剪力滞效应的影响．结果表明：二、三次抛物线均不是最合理的位移模式；连续箱梁的剪力滞效应受翘曲位移模式的影响很小；轴力平衡条件对应力分布的影响亦很小．

英文摘要：

The warping displacement pattern of cubic parabolic curve is chosen on the axial force equilibrium condition. In order to reflect the stress distribution in the box girder more rationally, the width of the canti- lever plate and the distance form the top and bottom flange plates to the centre axis are fully considered. Formulas of the moment of inertia, product of inertia and sectional area for shear lag warping geometrical properties are deduced. The equations of equilibrium with considering the shear lag for thin-walled box girders are established on the basis of the variation principle. The calculation formulas and bounding conditions of shear lag effect of the continuous box girder are deduced by adopting the finite difference solution. The Shell63 unit of Ansys program is used to analyze the distributions of shear lag effect for three-span continuous box girder. The influence of distributions by longitudinal warping displacement patterns and axial force equilibrium condition is analyzed. The results show that neither of the warping displacement patterns of quadratic nor cubic parabolic curve is the most reasonable mode. The influence of distributions of continuous box girder by axial force equilibrium is little and so do the longitudinal warping displacement patterns.