薄壁钢管混凝土长柱轴压性能试验研究

Experimental Research on Static Behavior of Axially Loaded Long Column of Concrete-filled Thin-walled Steel Tube

对 8根方形和八边形薄壁钢管混凝土长柱的轴压性能进行了试验研究 ,柱的长宽比为 1 4～ 40 ,管壁板件的宽厚比为 67～ 1 2 5。试验结果表明 ,方形薄壁钢管混凝土长柱的轴压破坏为弯曲屈曲破坏 ,八边形薄壁钢管混凝土长柱的破坏主要表现为强度破坏 ,破坏之前钢管均发生了局部屈曲现象。柱子的承载力随着长细比的增加而显著下降。在薄壁钢管混凝土短柱试验结果的基础上 ,线性回归了方形轴压长柱极限承载力折减系数 ,在上述长宽比的范围内 。

Experiments have been carried out to 8 long columns of concrete-filled thin-walled steel tube under axial load. Their cross-sections are square or octagon. The length-width ratio of the columns is 14～40, and the width-thickness ratio of the tube plates is 67～125. The experimental results show that damage mode of the square long columns is flexural buckling failure, and that of the octagon long columns is mainly strength failure. The local buckling occurs in the plates of the steel tube before failure. The ultimate load greatly drops with the increasing of slenderness ratio of the column. Based on the experimental results of stub columns of concrete-filled thin-walled steel tube, the ultimate load reduction factor is linearly regressed counting for the effect of slenderness ratio. The calculation results are basically identical with experimental ones.