ABSTRACT An analytical model was developed that accounted for double confinement provided by both transverse reinforcements and wide flange steel sections in the compression zone. This study also found that the amount of confinements was very sensitive to the post-yield behavior of the composite columns, especially when the buckling in compression region occurred. The nominal moment capacity and post-yield structural behavior of the composite columns were then calculated. The results were verified by comparison to numerical nonlinear finite element analysis results. The model was also verified experimentally. The post-yield behavior of the composite columns obtained from previous experimental studies and nonlinear finite element analysis based on concrete plasticity agreed well with those of the analytical results presented in this study, demonstrating a reliable and fast evaluation of the post-yield behavior of the composite actions. Fracture criteria for the concrete encasing steel columns under axial and lateral loads were also proposed based on the confinement offered by the steel sections encased in concrete. The new concept engaged in the estimation of the flexural strength of concrete columns confined by encased steel sections added innovations to the state of the art in the body of knowledge and advancement of the composite frames. GRAPHICAL ABSTRACT

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计算由横向钢筋和钢截面约束的混凝土柱的抗弯强度和性能的分析模型

摘要 开发了一种分析模型，该模型考虑了受压区横向钢筋和宽翼缘钢截面提供的双重约束。本研究还发现，约束量对复合柱的屈服后行为非常敏感，尤其是在压缩区域发生屈曲时。然后计算组合柱的标称弯矩承载力和屈服后结构行为。通过与数值非线性有限元分析结果进行比较来验证结果。该模型也得到了实验验证。从先前的实验研究和基于混凝土塑性的非线性有限元分析中获得的组合柱的屈服后行为与本研究中提出的分析结果非常吻合，展示了对复合动作的屈服后行为的可靠和快速评估。还根据混凝土中钢截面提供的约束，提出了在轴向和侧向荷载下混凝土包围钢柱的断裂标准。用于估计由包裹钢截面约束的混凝土柱的抗弯强度的新概念为复合框架的知识和进步的现有技术水平增加了创新。图形概要 用于估计由包裹钢截面约束的混凝土柱的抗弯强度的新概念为复合框架的知识和进步的现有技术水平增加了创新。图形概要 用于估计由包裹钢截面约束的混凝土柱的抗弯强度的新概念为复合框架的知识和进步的现有技术水平增加了创新。图形概要