贯通隔板全螺栓节点抗连续倒塌分析

Analysis of progressive collapse resistance of through diaphragm bolted joints

以钢管混凝土隔板贯通式全螺栓节点为研究对象,设计了一个三柱两跨式平面框架结构,采用静力加载的方式模拟结构倒塌的全过程,考察节点的受力变形、抗力机制、破坏现象和应变发展.建立ABAQUS有限元模型对结构失效模式进行受力分析.试验和有限元结果表明,倒塌全过程经历4个阶段:梁机制、混合作用、悬线作用和破坏.结构的抗倒塌能力取决于抗弯和抗拉能力,设计节点可以满足FEMA-365的转角要求,结构中的悬线作用出现在破坏阶段前.构件破坏发生在中节点H型梁下翼缘处,孔壁撕裂导致裂缝延伸至腹板使H型梁出现断裂.由于螺栓孔对翼缘的削弱,建议对螺栓连接H型钢翼缘进行构造加强,以保证连接的有效性.

A three-column two-span plane frame structure is designed based on a concretefilled steel tubular diaphragm through bolted joints.The entire process of collapse is simulated by static loading,and the mechanical deformation,resistance mechanism,failure phenomenon,and strain development of the joints are investigated.An ABAQUS finite element model is established to analyse the structural failure mode.Experimental and finite element results show that the collapse process can be divided into four stages:beam mechanism,mixed action,catenary action,and failure.The collapse resistance of the structure depends on both the bending and tensile capacities.The designed joints can meet the rotation requirements of FEMA-365,and the catenary action in the structure occurs prior to the failure stage.In addition,structure component failure occurs at the lower flange of the middle node H-beam,and the hole wall tearing causes the crack to extend to the web plate,which in turn generates a fracture in the H-beam.Because of the weakening of the flanges by bolt holes,it is suggested that the flanges of bolted H-section steel should be strengthened to ensure the effectiveness of the connection.