考虑截面配筋的变截面悬臂梁剪力滞效应研究
Study on shear lag effect of varying section cantilever beam in consideration of section reinforcement

基于选定的三次抛物线剪滞翘曲位移函数，采用能量变分法推导出考虑截面配筋后的剪力滞控制微分方程，研究截面配筋对变截面悬臂箱梁剪力滞效应的影响。结合实际施工案例，利用差分法计算分析了不同荷载作用下，不同配筋率时施工至最大悬臂状态的箱梁剪力滞效应。研究结果表明：截面配筋对变截面悬臂箱梁剪力滞效应有一定影响，随着配筋率的增大，不同类型荷载作用下附加弯矩均增大，但箱梁不同部位的剪力滞系数变化不同。均布荷载作用下，剪力滞系数最大增加5.16%，最大减少24.42%；集中荷载作用下剪力滞系数最大增加2.77%，最大减少1.92%。
In order to study the effect of section reinforcement on the shear lag effect of varying section cantilever box girder, the governing differential equations of the shear lag were derived based on the energy variation method and cubic parabola warping displacement function. Combined with the actual construction case, the shear lag effect of the cantilever beam with respect to different reinforcement ratios and different loads was calculated and analyzed by the finite difference solution. The results show that the section reinforcement of varying section cantilever box girder should have some influence on the shear lag effect, and with the increase of reinforcement ratio, the additional bending moment increases under different types of loads. But the change of the shear lag coefficient in different parts of the box girder is different. Under uniform load, the shear lag coefficient increases to up to 5.14% and reduced up to 24.42%; the maximum increase of shear lag coefficient under concentrated load is 2.77%, and the maximum decrease is 1.92%