圆端形钢管混凝土柱轴压性能研究

Behavior of concrete-filled round-end steel tubular stub columns under axial compression

通过17个圆端形钢管混凝土轴压短柱的试验,研究圆端形钢管混凝土轴压短柱在不同的截面高宽比、含钢率和构造措施的破坏特征和轴压力学性能。试验结果表明:圆端形钢管对核心混凝土具有良好的约束作用;纵向隔板或对拉杆可有效延缓钢管壁的局部屈曲;同时采用纵向隔板或对拉杆还可有效提高试件的承载力和延性。从提高该构件承载力而言,对拉杆件效果更显著;从延性角度,设置纵向隔板效果更好。采用有限元分析软件ABAQUS对圆端形钢管混凝土轴压短柱进行分析,有限元分析结果和试验结果吻合良好。在已有矩形钢管混凝土轴压短柱承载力简化计算公式的基础上,建议了带纵向隔板的圆端形钢管混凝土轴压短柱的承载力简化计算式。当钢管壁平直段的宽厚比大于60时,建议设置纵向隔板或对拉杆。

A total of 17 tests of concrete-filled round-end steel tubular stub columns under axial compression were carried out with different sectional aspect ratios,steel ratios and the structural measures. The failure characteristics and the behavior of the composite column under axial compressive load were exhibited. It can be found from experiments that core concrete can be confined by the steel tube. The local buckling can be avoided by the longitudinal diaphragm or the binding bar. The longitudinal diaphragm or the binding bar can be used to improve the strength and ductility. For strength,the binding bar is better than the longitudinal diaphragm. But for ductility,the reverse is true.The finite element( FE) soft ABAQUS was used to analyze the behavior of concrete-filled round-end steel tubular stub columns. The FE results agree well with experimental ones. Based on existing simplified strength models of the concrete-filled rectangular steel tubular stub column under axial compression,a simplified strength model was proposed to predict the load carrying-capacity of concrete-filled round-end steel tubular stub columns with the longitudinal diaphragm under axial compression. In addition,the longitudinal diaphragm or the binding bar is suggested to be applied when the width to thickness ratio of the flat of the steel tube is more than 60.