钢管混凝土叠合柱轴压性能研究

为研究钢管混凝土叠合柱轴压性能，基于合理的钢材和混凝土本构关系模型，采用纤维模型法和有限元法分析方法计算叠合柱轴压荷载-变形关系曲线。将理论计算结果与试验结果进行对比，验证了理论分析模型的正确性。在此基础上，对叠合柱的破坏模态、轴向荷载分配以及组成钢管混凝土叠合柱的外围钢筋混凝土、钢管和钢管内部混凝土之间相互作用等进行分析，提出了叠合柱的轴压承载力简化计算式，简化计算结果与试验结果吻合较好。为保证外围钢筋混凝土和内部钢管混凝土较好地协同工作，建议外围钢筋混凝土中箍筋的约束指标与内部钢管混凝土的约束效应系数比值不应小于0.188。

Behavior of concrete-filled steel tube reinforced concrete columns subjected to axial compression

Based on rational constitutive models of steel and concrete, load-deformation relationship curves of concrete-filled steel tube (CFST) reinforced concrete columns subjected to axial compression were calculated by the fiber model method and finite element method to investigate the behavior of composite column subjected to axial compression. The results of theoretical analysis are in good agreement with the experimental ones. Based on the research conclusion mentioned above, behavior analysis of concrete-filled steel tube reinforced concrete columns subjected to axial compression including failure mode, axial load distribution, and the interaction between outer concrete, steel tube and core concrete were carried out. Practical simplified formulae of bearing capacity were proposed, and results calculated using the formulae agreed well with test results. At last, it is suggested that in order to ensure the collaborating between outer concrete and inner concrete filled steel tube, the ratio of stirrup constraint index in outer concrete to constraint effect coefficient in inner concrete filled steel tube should not be less than 0.188.