基于统一强度理论的多室T形钢管混凝土短柱轴压承载力

Axial compressive bearing capacity of multi-cell T-shaped concrete-filled steel tubular column based on unified strength theory

为研究多室T形钢管混凝土柱的轴压性能,将多室T形钢管混凝土柱等效成两个正方形和一个矩形钢管混凝土柱,对于矩形钢管混凝土柱,考虑长边和短边对核心混凝土的不同约束作用,将矩形钢管对核心混凝土产生的约束力等效成圆钢管对核心混凝土产生的均匀约束力,并引入混凝土折减系数。对于等效成圆钢管后直径小于100 mm的小尺寸方钢管混凝土柱,假定混凝土折减系数为1。利用统一强度理论分别求出两种钢管内部核心混凝土轴压强度,将钢管部分轴压承载力和两种钢管内部核心混凝土轴压承载力进行相加,得出整体的轴压承载力。计算结果与试验结果吻合较好,说明所建立的理论公式可以精确地计算多室T形钢管混凝土短柱的轴压承载力。

In order to study the axial compressive bearing capacity of multi-cell T-shaped concrete- filled steel tubular （MT-CFST） columns,a MT-CFST column was equivalent to two square and one rectangle CFST columns. For the rectangle CFST column,the lateral force of the rectangle steel tube to core-concrete was simplified to a uniform lateral force of a cylinder steel tube to the core-concrete by considering the different restriction effect on the core-concrete from broad and narrow faces,and a concrete reduction factor was adopted. For the small square CFST columns,the diameter of their equivalent circular tube was less than 100 mm,and the concrete reduction factor was assumed to be1. Based on the unified strength theory, the axial compressive strength of the two kinds of core-concrete was calculated separately. By adding the axial compressive bearing capacity of steel tube to the capacity of the two kinds of core-concrete, the axial compressive bearing capacity of the entire MT-CFST column was obtained. It is found that the conformity is good by comparing the calculated results and the experimental results. It illustrates that the established formula can be used for accurate prediction of the axial compressive bearing capacity of MT-CFST short columns.