Abstract The calculation of the ultimate loading capacity of composite frame beams is an important step in the design of composite frame structural systems. This paper puts forward the Compression-on-Column-Face, Compression-on-Transverse-Beam and Tension-on-Transverse-Beam mechanisms to explain the mechanism of the circular-section column frame in the ultimate loading state, and an extensive parametric analysis is conducted on a series of typical composite beam–column joint subassemblies using the nonlinear finite-element simulation method. First, an elasto-plastic elaborate finite element model is established to conduct the parametric analysis of the exterior joint of the circular-section column frame under negative and positive moment. Furthermore, based on the parametric analysis, the simplified design formulae of the slab effective width are derived. The proposed formulae and numerical results are compared for the effective slab width for composite frames with circular-section columns, and the relative errors are little. In addition, the applicability of the formulae to calculate the effective slab width at the interior joints in the circular-section column frame is verified. Finally, this paper compares the proposed formulae with formulae in the current design codes, and the proposed formulae provide the most accurate results to predict the effective slab width and ultimate loading capacity.

中文翻译：

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圆截面柱组合框架梁端抗弯强度的有效板宽

摘要 组合框架梁极限承载力的计算是组合框架结构体系设计中的一个重要步骤。本文提出了柱面受压、横梁受压和横梁受拉机制来解释圆截面柱框架在极限荷载状态下的作用机理，并提出了广泛的参数化使用非线性有限元模拟方法对一系列典型的组合梁柱节点组件进行分析。首先，建立弹塑性精细有限元模型，对圆截面柱框架在正负弯矩作用下的外部节点进行参数化分析。此外，基于参数分析，推导出板坯有效宽度的简化设计公式。对圆截面柱组合框架的有效楼板宽度计算公式和数值结果进行了比较，相对误差较小。此外，验证了计算公式在圆截面柱框架内部节点处的有效板宽度的适用性。最后，本文将所提出的公式与现行设计规范中的公式进行了比较，所提出的公式为预测有效板坯宽度和极限承载力提供了最准确的结果。验证了公式计算圆截面柱框架内节点有效板宽的适用性。最后，本文将所提出的公式与现行设计规范中的公式进行了比较，所提出的公式为预测有效板坯宽度和极限承载力提供了最准确的结果。验证了公式计算圆截面柱框架内节点有效板宽的适用性。最后，本文将所提出的公式与现行设计规范中的公式进行了比较，所提出的公式为预测有效板坯宽度和极限承载力提供了最准确的结果。