圆CFRP-钢复合管约束高强混凝土短柱轴压试验研究

为研究圆CFRP-钢复合管约束高强混凝土短柱轴压受力性能，进行了6个CFRP-钢复合管约束高强混凝土（CFRP-steel composite tubed high-strength concrete，C-STC）柱和2个CFRP约束高强混凝土（CFRP-confined high-strength concrete，CC）柱、1个钢管约束高强混凝土（steel tubed high-strength concrete，STC）柱对比试件的轴压试验研究，得到了试件轴向荷载-位移曲线和CFRP及钢管的应变。结果表明：C-STC柱在轴压荷载作用下发生剪切破坏；约束模式对其前期刚度影响较小，相同CFRP层数的C-STC柱和CC柱的荷载-位移曲线第二线性段斜率近似相等；随着CFRP层数增多，短柱承载力和变形能力均能得到提高；钢管应力分析表明，STC柱钢管在峰值荷载附近屈服，C-STC柱钢管约在荷载-位移曲线第二线性段起点处屈服，钢材强度得到充分发挥。结合试验结果对已有文献中约束混凝土强度计算模型进行验证，并给出了建议的C-STC柱承载力计算式。

Experimental study on axial behavior of circular CFRP-steel composite tubed high-strength concrete stub columns

In order to investigate the axial mechanical behavior of circular CFRP-steel composite tubed high-strength concrete stub columns, the axial compression tests on six CFRP-steel composite tubed high-strength concrete (C-STC) columns, two CFRP confined high-strength concrete (CC) columns and one steel tubed high-strength concrete (STC) column designed for comparison were carried out. The axial load versus deformation curves of specimens and strain of CFRP and steel tubes were obtained. The test results show that the failure mode of C-STC columns under axial compression is characterized as shear failure. The type of confinement has a little influence on the initial stiffness of specimens and the slope of the second linear part of the load versus deformation curves of C-STC column is similar to that of CC column. The bearing capacity and deformation capacity of stub columns can be improved along with the increase of CFRP layers. The stress analysis of steel tube indicates that the steel tube of STC columns yields near the peak load, whereas the steel tube of C-STC columns yields approximately at the initial point of the second linear part of the load versus deformation curves, which indicating a better utilization of the strength of steel tube. Based on the test results, existing calculation methods on the load bearing capacity in existing references were verified, as well as the recommended calculation formula towards the strength of C-STC columns was proposed.