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针对结构抗震设计对延性的要求,对不同轴压比、长细比和混凝土标号的7根方钢管混凝土柱试件进行了低周反复加载实验,得到了框架柱的荷载位移曲线、骨架曲线以及各阶段的荷载位移值,据此分析了各种因素对方钢管混凝土柱延性的影响。实验结果表明:剪力滞引发了方钢管混凝土柱的塑性铰,塑性铰的扩展是柱端承载力下降的根本原因,增大轴压比将引起塑性铰更早出现,进而降低框架柱的延性和水平抗剪能力;增大长细比可以延缓塑性铰出现,提高柱的延性和耗能能力,但是水平抗剪能力下降;提高混凝土强度等级可以降低大轴压比、大长细比带来的不利因素。实验结果与有限元计算数据吻合良好。
According to the requirement of ductility of seismic design of structures, seven steel tube concrete columns with different axial compression ratio, slenderness ratio and concrete designation were repeatedly loaded in low cycle, and the load displacement curve, the skeleton curve As well as the load displacement value of each stage, the influence of various factors on the ductility of concrete filled square steel tubular columns is analyzed. The experimental results show that shear lag initiates the plastic hinge of concrete filled square steel tube column. The expansion of plastic hinge is the fundamental reason for the decrease of bearing capacity at the column end. Increasing the axial compression ratio will cause the plastic hinge to appear earlier and reduce the ductility And the level of shear resistance; increase the slenderness ratio can delay the emergence of plastic hinge to improve the ductility and energy dissipation capacity of the column, but the level of shear capacity decreased; to improve the strength level of concrete can reduce the large axial compression ratio, large slenderness ratio brought Unfavorable factors. The experimental results are in good agreement with the finite element analysis data.