梁贯通型RCS组合结构梁柱节点抗连续倒塌研究

为研究钢筋混凝土柱 钢梁(RCS)组合结构在拆除底层第2根侧边柱工况(最危险工况)下节点的抗连续性倒塌性能与机理，试验以梁翼缘切割式的梁贯通型RCS结构节点构件为研究对象，通过梁跨度差异模拟第2根侧边柱失效时剩余结构抗侧移刚度及梁端约束能力不同的特点，采用静力加载的方式模拟非对称倒塌破坏全过程。研究试验曲线特征与破坏模式，分析试件节点控制截面内力发展情况与抗力机制。结果表明：底层第2根侧边柱失效后的梁贯通型RCS结构节点的受力薄弱部位出现在梁上翼缘，且易首先在侧向刚度较小一侧的上翼缘出现局部屈曲，结构的抗力机制由梁抗弯机制转变为抗弯机制与悬链线机制共同作用，之后由于该侧上翼缘及腹板发生严重局部屈曲，导致结构在充分发挥悬链线效应之前发生非对称破坏。

Experimental and numerical investigation on progressive collapse resistance of #br#beam-column joints in beam-through RCS composite frame structures

 In order to study the performance and mechanism of progressive collapse resistance of RC column-steel beam (RCS) composite structure under the condition of removing penultimate column (the most dangerous condition), the experiment took the beam flange cut through RCS structure joint members as the research object, and the characteristics of different lateral stiffness and beam end restraint capacity of the remaining structure when penultimate column fails were simulated by the difference of beam span. The characteristics of test curve and failure mode were studied, and the development of internal force and resistance mechanism of control section were analyzed. The results show that: after the failure of the second side column in the bottom layer, the weak part of the beam through RCS structure joint appears on the upper flange of the beam, and it is easy to appear local buckling at the upper flange of the side with less lateral stiffness; the resistance mechanism of the structure is changed from the beam bending mechanism to the joint action of the bending mechanism and the catenary mechanism. Then, due to the severe local buckling of the upper flange and web, the structure will be destroyed asymmetrically before the catenary effect is fully exerted.