简支组合箱梁在横向对称荷载作用下的解析解及剪力滞研究

A Closed-Form Solution of Load Effect and Study of Shear Lag Effect for Simple Steel-Concrete Composite Box Beam

对于上下翼缘宽度都较大的钢-混凝土组合箱梁,分别考虑了钢梁底板、混凝土顶板和悬臂板由剪力滞效应引起的纵向翘曲,以及钢梁与混凝土板之间的相对滑移,在线弹性阶段采用位移叠加的概念,根据能量变分原理建立了钢-混凝土简支组合箱梁平衡微分方程,得到了均布荷载和集中荷载作用下的应力和挠度的解析解,并将解析解与试验结果及ANSYS软件的计算结果进行了相互验证。通过对组合梁荷载效应的参数研究,发现剪滞效应和钢梁与混凝土板之间的滑移效应存在耦合关系,滑移效应的增大使剪滞效应缓解,但使滑移变形和组合梁的挠度增大。结果还表明,不同荷载类型所产生的剪滞系数沿梁轴的分布有明显差别。

Considering the longitudinal warping deformation of steel bottom slab, concrete middle and cantilever slab, and the relative slip between concrete slab and steel beam, the balanced differential equations of simple steel-concrete composite box beam with wide flanges is analyzed using energy-variational and displacement superposition principle, the elastic closed-form solutions of stress and flexibility under uniform and concentrate load are deduced, and validated by the results of test and ANSYS. By the parameter analysis of the load effect, it is indicated that there exists couple relation between the shear lag effect and the slip effect, the increase of slip effect makes the shear lag effect decrease, but the slip deformation and flexibility of composite beam increase. At the same time, the analysis also shows that there is apparently difference between the distribution of the shear lag coefficient along the beam axis under different load type.