Abstract The concrete-filled steel tube (CFST) column circumferentially confined by carbon fibre reinforced polymer (CFRP), i.e. CFRP-CFST column, is a promising structural member in engineering practice. In this paper, the torsional capacity of CFRP-CFST columns was investigated by means of finite element (FE) simulation and theoretical derivation. Comprehensive FE models were established considering suitable material constitutive laws and interface relationships, which were then verified by experiment results. Besides, parametric analysis was conducted to reveal the geometrical and material parameters' effects on the torsional capacity of CFRP-CFST columns. The results show that the yield strength, the thickness, and the outer diameter of the steel tube are the most influential factors, and the number of CFRP layers also affects the torsional capacity considerably. Meanwhile, the comparison between the CFRP-CFST and CFST column indicates that the confinement effect provided by the CFRP can enhance the torsional capacity. Finally, equations for calculating the torsional capacity of the CFRP-CFST column were proposed and proved to be accurate through comparison with the test data.

中文翻译：

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CFRP周向约束钢管混凝土柱的抗扭能力

摘要 碳纤维增强聚合物（CFRP）周向约束的钢管混凝土（CFST）柱，即CFRP-CFST柱，是工程实践中一种很有前景的结构构件。在本文中，CFRP-CFST 柱的抗扭能力通过有限元 (FE) 模拟和理论推导进行了研究。考虑合适的材料本构规律和界面关系建立了综合有限元模型，然后通过实验结果进行验证。此外，还进行了参数分析，以揭示几何和材料参数对 CFRP-CFST 柱抗扭能力的影响。结果表明，钢管的屈服强度、厚度和外径是影响最大的因素，CFRP 层数也显着影响抗扭能力。同时，CFRP-CFST和CFST柱的比较表明，CFRP提供的约束效应可以提高抗扭能力。最后，提出了计算CFRP-CFST柱抗扭能力的公式，并通过与试验数据的对比证明了其正确性。