带约束拉杆方钢管混凝土短柱轴压性能试验研究

Investigation of Behavior of Square CFT Stub Columns with Binding Bars Under Axial Loads

进行了10个带约束拉杆和5个不设约束拉杆方形钢管混凝土短柱轴心受压构件的试验研究。主要研究参数为约束拉杆直径和间距、钢管厚度、钢材强度等。试验研究表明,在轴心压力作用下,方形钢管混凝土短柱在设置了约束拉杆后,能有效改善横截面周边中部钢管对核心混凝土的约束作用,延迟或避免钢管在应力达到屈服强度前发生失稳性的局部屈曲而导致构件的过早破坏,从而使方形钢管混凝土轴压短柱的承载力和延性均有较大幅度的提高。同时,应用现有规范及规程有关方形钢管混凝土承载力计算公式,对带约束拉杆方形钢管混凝土轴压试件承载力进行计算,计算结果与试验结果相比较为保守。

The behavior of square concrete-filled steel tubular （CFT） stub columns with binding bars subjected to axially loading is experimentally investigated, including 10 specimens with binding bars and J ones without binding bars. The main parameters are diameter and space of binding bars, width-thickness ratio and strength of steel plate. It is shown that the binding bars help improving the confinement effect on concrete core in the middle of four sides of cross-section supplied by steel plate and delay or even avoid the development of local buckling of the steel tube before it attains yield strength, which thus increases the ultimate load and ductility of square CFT stub columns under axial compressive loads. The ultimate bearing capacity of the specimens, calculated by the methods of current specifications and codes is quite conservative, compared with the experimental results.