柱贯通梁柱节点非对称钢筋混凝土柱-钢梁框架结构抗连续倒塌性能研究

建筑结构竖向连续倒塌破坏大多数由侧中柱破坏引起，而侧中柱两侧结构的抗侧刚度不同，易导致结构沿侧中柱发生非对称破坏。已有文献中对非对称连续倒塌研究相对较少，鉴于此，以非对称双半跨单柱子结构为研究对象，设计了1种钢筋混凝土柱-钢梁(RCS)结构全螺栓连接的柱贯通节点子结构，采用静力加载试验模拟结构在侧中柱失效工况下的非对称倒塌破坏全过程。以不等跨梁模拟两侧结构抗侧刚度差异，结合有限元分析考察子结构连续性倒塌的受力机理及破坏形态，并与传统对称双半跨子结构抗连续性倒塌性能进行对比。结果表明，柱贯通RCS结构全螺栓连接子结构在侧中柱失效的情况下，侧向刚度较小一侧的梁上翼缘先出现局部屈曲，梁端的转动能力小于中柱失效工况，且不能充分发挥结构的悬链线效应，抗连续倒塌能力也较中柱失效工况的低，但是试验和有限元分析得到的梁端极限转角均高于DoD规范中规定的转角允许限值，表明采用DoD规范评估柱贯通全螺栓连接RCS结构抗连续倒塌性能时偏于保守。

Investigation on progressive collapse behavior of column-through beam-column joints in asymmetric RCS frame structure

Most of the structural vertical progressive collapse failures are caused by the failure of side column. Since the lateral stiffness of the structures on both sides of the failure column are different, the asymmetric destruction of the structures along the failure column may occur. Since there is few research on asymmetric progressive collapse in existing literature, the asymmetric double-half-span single-column structure was taken as the research object, and a column-through beam-column joint substructure with full bolted connections for reinforced concrete column-steel beam (RCS) structure was designed. The complete process of asymmetric collapse and destruction of the structure under the failure of side column was simulated through static loading test. The difference of lateral stiffness of columns between the two sides of the substructure was simulated through unequal frame span. Meanwhile, the mechanical mechanism and failure modes of the substructure under progressive collapse were investigated using finite element analysis. The results were compared with those of traditional symmetrical double-half-span substructures. It is found that the upper flange of the side with smaller lateral stiffness sustains local buckling firstly when the full bolted connection substructure fails. Moreover, the rotational capacity of the beam end is less than that with middle column failure. The catenary effect of the structure cannot be fully exerted, which also causes the anti-progressive collapse capacity lower than those structures with middle column failure. However, the ultimate rotation angle of the beam end obtained from the test and finite element analysis is higher than the allowable limit of rotation specified in DoD, indicating that DoD is conservative for evaluating the progressive collapse capacity for the fully bolted connections in this type of column-through RCS structure.