【摘要】 针对轨道交通“双U+箱形”组合梁截面，通过分析其竖向弯曲时截面上的剪力流分布规律，引入顶板悬挑段与顶板、底板与顶板剪力流的比来反映截面剪力流对剪切变形的影响，定义各翼板符合其剪切变形规律的翘曲位移函数，基于能量变分法推导剪力滞的控制微分方程，建立连续梁剪力滞效应简化计算方法。以“双U+箱形”组合连续梁为算例，将自重和轨检车荷载单独作用下的剪力滞系数解析解与有限元结果进行对比分析，并讨论梁高和腹板厚度对剪力滞效应的影响。结果表明：按简化计算方法得到的应力与有限元结果吻合较好，轨检车荷载作用下的剪力滞效应比均布荷载作用下的更为明显，且梁高和腹板厚度的变化会减弱截面的剪力滞效应。本文提出的简化计算方法可为复杂截面连续桥梁安全评估提供参考。更多还原

【Abstract】 By analyzing the distribution law of shear flow on the “double-U-box” composite girder cross-section in rail transportation, the shear flow ratios of the top plate cantilever section to the top plate and of the bottom plate to the top plate were introduced to reflect the effects of the cross-section shear flow on the shear deformation. The warping displacement function of each flange plate was defined in accordance with its shear deformation. Based on the energy variation method, the shear lag governing differential equation was derived and the simplified analytical method for shear lag effect of continuous beam was established. The analytical solution of shear lag coefficient under the independent action of self weight and rail inspection vehicle load was compared with the finite element results using the “double-U-box”composite continuous girder as an example, and the effects of beam height, web thickness on shear lag effect were discussed. Results showed that the stress obtained by the simplified analytical method was in good agreement with the finite element results. The shear lag effect under the rail inspection vehicle load was more obvious than that under the uniformly distributed load, and the shear lag effect of the section was reduced by the change in beam height and web thickness. The simplified analytical method proposed in this paper can provide a reference for the safety assessment of continuous bridges with complex cross sections.更多还原