The developments of compressive arch action (CAA) and tensile catenary action (TCA) in beams can provide secondary loads for resisting progressive collapse. However, to date, the contributions of CAA and TCA in regards to progressive collapse have not been considered in design codes, owing to inadequate studies. In this study, a division of resistant mechanisms was initially proposed. Then, based on an experimental model of beam-column subassemblages, a finite-element model was established using ABAQUS software, and was validated against experimental results. Subsequently, the calibrated finite element model was employed to study the effects of different constraints (such as ideal fixed constraints, sliding constraints, the beam-column stiffness ratio, and axial compression ratio) on the secondary progressive collapse-resistance mechanisms of reinforced concrete (RC) subassemblages. The results show that when the constraints are weaker than the fixed supports, the CAA capacity is larger than that of the TCA. The axial compression ratio in the column slightly increases the first peak load, but the beam-column subassemblages fail earlier, owing to the large eccentric bending moment. The CAA capacity and TCA capacity increase with a decreasing beam-stiffness ratio, and the CAA capacity increases faster than the TCA capacity. In addition, a theoretical model is proposed for assessing the resistance provided by a CAA.

中文翻译：

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钢筋混凝土构件二次连续倒塌抗力机理研究

梁中压缩拱作用（CAA）和拉伸悬链线作用（TCA）的发展可以为抵抗连续倒塌提供二次载荷。然而，迄今为止，由于研究不足，CAA 和 TCA 对连续倒塌的贡献尚未在设计规范中考虑。在这项研究中，最初提出了耐药机制的划分。然后，基于梁柱组合实验模型，利用ABAQUS软件建立有限元模型，并与实验结果进行验证。随后，利用标定后的有限元模型研究了不同约束条件（如理想固定约束、滑动约束、梁柱刚度比、和轴压比）对钢筋混凝土 (RC) 组件的二次连续倒塌抗力机制的影响。结果表明，当约束弱于固定支撑时，CAA容量大于TCA。柱中的轴压比略微增加了第一个峰值载荷，但由于偏心弯矩较大，梁柱组件失效较早。CAA容量和TCA容量随着波束刚度比的减小而增加，并且CAA容量比TCA容量增加得更快。此外，还提出了一个理论模型来评估 CAA 提供的阻力。柱中的轴压比略微增加了第一个峰值载荷，但由于偏心弯矩较大，梁柱组件失效较早。CAA容量和TCA容量随着波束刚度比的减小而增加，并且CAA容量比TCA容量增加得更快。此外，还提出了一个理论模型来评估 CAA 提供的阻力。柱中的轴压比略微增加了第一个峰值载荷，但由于偏心弯矩较大，梁柱组件失效较早。CAA容量和TCA容量随着波束刚度比的减小而增加，并且CAA容量比TCA容量增加得更快。此外，还提出了一个理论模型来评估 CAA 提供的阻力。