热成型不锈钢圆管混凝土轴压短柱受力性能试验研究

对热成型不锈钢圆管混凝土短柱在轴向压力作用下的承载性能进行试验研究，试验主要参数为混凝土强度（C30和C40）、不锈钢管壁厚t（0.9 mm、1.0 mm和1.2 mm）和试件的高径比λ（3.0、3.5、4.0），试验观测了不锈钢圆管混凝土短柱在轴向压力作用下的破坏现象、试件荷载-轴向变形曲线、荷载-环向应变曲线、荷载-轴向应变曲线等。根据试验的破坏现象，将试件分为5种破坏模式，并分析了不锈钢管壁厚t和试件的高径比λ对试件的承载力、延性、刚度的影响。分析结果表明：试件在屈服后表现出明显的承载力提高；随着钢管壁厚的增加，试件的受压承载力、延性及刚度均有所提高；随着试件高径比增大，试件的延性增大，刚度降低；试件的受压承载力在高径比3.5时最大，4.0时次之，3.0时最小。与普通钢管混凝土相比，不锈钢管混凝土约束放大系数有一定的提高。

Experimental study on axial compressive behavior of concrete-filled thermoforming stainless steel tubular stub columns

This paper presents an experimental study on axial compressive behavior of concrete filled thermoforming stainless steel tubular(CFTSST) stub columns. Seventeen specimens of CFTSST stub columns with different parameters were tested under axial compression. The parameters in the study included the compressive strength of concrete (C30 and C40),wall thickness of thermoforming stainless steel t (0.9 mm,1.0 mm,1.2 mm) and height-diameter ratio of specimens λ(3.0, 3.5 and 4.0). This paper presents test procedure, specimens failure phenomena, load-axial displacement curves, load-circular strain curves and load-axial strain curves. Based on the failure phenomena, all specimens were divided into 5 failure modes. The effects of t and λ on compressive ultimate capacity, ductility and stiffness were investigated. The results of tests show that the stress of specimens increases greatly at the end of the yield stage; as value of t increases, compressive ultimate capacity, ductility and stiffness of specimens increase; as value of λ increases, ductility increases, stiffness decreases; the value of compressive ultimate capacity gets maximum when the value of λ is 3.5, it is lower when λ is 4.0,gets minimum when λis 3.0; according to the comparisons between CFTSS tubular stub columns and concrete-filled steel tubular stub columns, the results show that the restraint amplification coefficient of CFTSS tubular stub columns is higher.