下承式脊骨梁横向剪力滞效应

Transverse shear lag effect of the through spine beam

下承式脊骨梁作为一种新型的城市轨道交通高架桥,具有小脊梁、大悬臂的特点.作为主梁的一部分,悬臂翼缘板也产生纵向弯曲,其横向剪力滞效应非常显著.本文采用ANSYS软件建立下承式脊骨梁的有限单元模型,计算了集中荷载及均布荷载作用下各横截面底板弯曲正应力,并与按初等梁理论的计算结果对比,得出横向剪力滞系数沿底板的分布规律.

The through spine beam is a new bridge type for urban rail transit, which has the structural properties of the small box girder and large cantilever. As the part of spine beam, cantilever plates is prone to longitudinal warping of beam, and the transversal shear lag effect is very obvious. FEA soft- ware ANSYS was introduced to construct the calculating model of through spine beam for urban rail transit. The bending normal stress in bottom plate under concentrated load and uniform distributing load were calculated and compared to the result of the Timoshenko beam theory. The distribution pat- tern of transverse shear lag coefficient is coneluded.