悬臂箱形截面梁的负剪力滞效应

Negative Shear Lag Effect of Cantilever Box Section Beams

为了研究考虑负剪力滞效应的混凝土悬臂箱梁承受均布荷载作用的力学响应问题,利用能量变分法的最小势能原理得到了箱梁纵向应力分布和负剪力滞变号位置。结果表明:作用均布荷载在悬臂箱梁顶板引起负剪力滞效应;距离固定端约l/4为负剪力滞效应的起点,为了提高悬臂箱梁承受均布荷载下整体稳定,设计中应充分考虑负剪力滞效应。

In order to study the mechanical response of a cantilever box girder with negative shear lag effect, the longitudinal stress distribution and the position of the negative shear lag number are obtained by using the minimum potential energy principle of the energy variational method. The results show that the negative shear lag effect is caused by the load uniformly distributed load on the roof of the cantilever box beam, and the distance to the fixed end is about l/4 as the starting point of the negative shear lag effect. In order to improve the overall stability of the cantilever box girder under the uniformly distributed load, the negative shear lag effect should be fully considered in the design.