钢筋混凝土框架结构底部相邻两柱失效的抗连续倒塌性能研究

为研究钢筋混凝土结构在角柱和相邻边柱同时失效情况下的抗连续倒塌性能，采用12点等效均布荷载加载系统，对移除角柱和相邻边柱后的钢筋混凝土梁-板-柱子结构进行PUSHDOWN加载，并对钢筋混凝土子结构的破坏模式、承载能力、变形能力、钢筋局部应变、支座水平位移及边梁扭转变形进行分析。试验结果表明：角柱和相邻边柱同时失效的钢筋混凝土梁-板-柱子结构反应与悬挑板相近，梁与板无法形成有效的压拱机制、悬链线机制或薄膜机制来抵抗连续倒塌的发生。采用有限元软件DIANA建模对试验结果进行了数值模拟分析，证明了数值模型的合理性。采用塑性铰线法对试验屈服荷载和第一极限荷载进行分析，理论分析结果表明，与试验结果相比，塑性铰线法的分析结果偏于保守。

Progressive collapse performance of reinforced concrete frame structures subjected to ground two-column removal scenario

A pushdown experiment was conducted for a beam-column-slab substructure after removal of the corner and penultimate exterior columns to investigate the progressive collapse behavior of reinforced concrete structures after removal of the corner and penultimate exterior columns. A 12-point equivalent loading system, which equivalently simulated the uniformly distributed load,was used. The failure modes, load resisting capacities, deformation capacity, local strain in reinforcements, horizontal movement of supports, and torsional rotations of edge beams of the beam-column-slab substructures were analysed. The experimental results indicate that when both corner and penultimate exterior columns are removed, the beam-column-slab substructure performs as a cantilever slab, no reliable compressive arch action, catenary action, membrane action could be developed to prevent the occurring of progressive collapse. A numerical model was built by finite element software DIANA. It is found that the model could simulate the global behavior of the specimen well. Yield-line model is utilized to predict the yield load and first peak load of the specimen. The theoretical results indicate that the yield-line method may achieve conservative results compared to the test results.