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进行了3个剪跨比为1.5的圆钢管约束钢筋混凝土短柱和1个钢筋混凝土对比试件的拟静力试验研究,试验中的主要参数为轴压比(0.35,0.45和0.55)。试验结果表明:钢筋混凝土短柱的破坏模式为剪切破坏,延性和变形能力很差;圆钢管约束钢筋混凝土短柱的破坏模式为弯曲破坏,延性和变形能力优越。外包钢管对核心混凝土的约束作用限制了核心混凝土的受剪开裂,改变了钢筋混凝土短柱的破坏模式,显著提高了钢筋混凝土短柱的受剪承载力、延性、变形能力和耗能性能。随轴压比的提高,圆钢管约束钢筋混凝土短柱的水平承载力提高,延性系数降低,但轴压比对圆钢管约束钢筋混凝土短柱的极限变形能力无明显影响。对钢管的弹塑性应力分析结果表明:水平荷载施加过程中,钢管并未受剪屈服。根据试验结果建立了圆钢管约束钢筋混凝土短柱的荷载-位移恢复力模型,提出了设计建议,可为工程实践提供参考。
A pseudo-static test study was conducted for three reinforced concrete short columns confined by a circular steel tube with a shear-span ratio of 1.5 and a comparative specimen of reinforced concrete. The main parameters in the test were axial compression ratios (0.35, 0.45, and 0.55). The test results show that the failure mode of reinforced concrete short columns is shear failure, and the ductility and deformation ability are poor. The failure mode of reinforced concrete short columns confined by round steel tubes is bending failure, and the ductility and deformation ability are superior. The constraint effect of the outer steel pipe on the core concrete limits the shear cracking of the core concrete, changes the failure mode of the reinforced concrete short column, and significantly improves the shear capacity, ductility, deformation capacity and energy dissipation performance of the reinforced concrete short column. With the increase of axial compression ratio, the horizontal bearing capacity of reinforced concrete short columns confined by round steel tube increases, and the ductility coefficient decreases, but the axial compression ratio has no obvious effect on the ultimate deformation capacity of the short steel reinforced concrete short columns confined by round steel tubes. The elasto-plastic stress analysis results of the steel tube show that the steel tube does not undergo shear yield during the application of the horizontal load. Based on the test results, a load-displacement restoring force model for a short steel-reinforced concrete short column confined by a round steel tube was established, and a design proposal was proposed, which could provide a reference for engineering practice.