钢筋混凝土框架抗连续倒塌的压拱机制分析模型

钢筋混凝土框架结构依靠梁板组成的楼盖系统来抵抗连续倒塌,其在小变形下的连续倒塌抗力由梁板内的压拱机制提供。现有压拱机制的宏观理论分析模型参数过多且不能考虑楼板的影响,因此难以在工程设计中进行应用。该文基于楼盖系统微观受力机理的分析,建立了压拱机制下梁板子结构系统的连续倒塌抗力分析模型。和现有模型相比,该文计算模型的参数大幅减少、公式显著简化,且能够考虑楼板和梁抵抗连续倒塌的共同作用。通过与国内外47个梁试件和6个梁板子结构试件的试验结果进行对比,发现该文计算模型在计算梁试件时计算精度和现有模型精度相同,而在计算梁板共同作用下的连续倒塌抗力时精度提高显著,能够为混凝土框架结构的抗连续倒塌工程设计提供参考。

AN ANALYTICAL MODEL OF COMPRESSIVE ARCH ACTION OF REINFORCED CONCRETE FRAMES TO RESIST PROGRESSIVE COLLAPSE

The reinforced concrete frame structures resist progressive collapse through the floor systems consisting of slabs and beams. The progressive collapse resistance of the floor systems under small deformation is provided by the compressive arch action of slabs and beams. The existing theoretical macro-model of the compressive arch action is complicated, involving many parameters but ignoring the influence of the slabs; as a result, the existing model is not feasible for the practical engineering design. Based on the micro-mechanism of the floor system, this paper establishes an analytical model of the progressive collapse resistance of the beam-slab substructures under the compressive arch mechanism. Compared with the existing model, the proposed model significantly reduces the number of the parameters and thus simplifies the formula to calculate the progressive collapse resistance. In addition, the interaction of the slabs and beams in resisting progressive collapse can be considered by this model. Through a comparison with the experimental results including 47 beam specimens and 6 beam-slab substructure specimens, it is found that the accuracy of the proposed model in calculating the beam specimens is comparable to the existing model. In addition, the calculating accuracy for the beam-slab specimens is improved significantly. This study provides a reference for the practical engineering design of the reinforced concrete frame structures to resist progressive collapse.