为探究梁跨中位置顶部钢筋布置方式对RC框架结构抗连续倒塌性能影响,设计并制作了两榀一层四跨的梁柱子结构失效柱模型,梁顶部钢筋分别按截断与通长两种方式布置,采用电液伺服作动器在失效柱上方施加持续增大的竖向荷载,对子结构进行拟静力抗连续倒塌试验.依据失效柱竖向位移荷载曲线及关键梁截面钢筋应变发展变化,得到梁跨中顶部钢筋布置方式影响结构抗连续倒塌性能规律.结果表明,结构依靠梁机制和悬链线机制作用来提供结构抗力,布置方式对前期的梁机制几乎不产生影响,对后期悬链线机制作用阶段影响较明显,通长布置的结构悬链线机制峰值抗力更大,且进入悬链线受拉阶段更加提前.%In order to investigate the influence of top reinforcement arrangement in middle span of beams of RC frame structure on its progressive collapse resistance, two one-layer and four-span beam-column failure substructures whose steel bars at the top of beam mid-span was respectively arranged as"truncated"or"full-length"were designed and prepared. By using an electro hydraulic servo actuator, a continuous vertical load is applied on the failure column, and a quasi-static collapse test is carried out. Based on vertical displacement load curve of the failure column and strain change of steel bars in key beam section, the influence of top reinforcement arrangement in beams of RC frame structure on progressive collapse resistance of the structure is obtained. The results show that structural progressive collapse resistance relies on beam mechanism and catenary mechanism. The reinforcement arrangement has little influence on beam mechanism at early stage, but has obvious effect on catenary mechanism at later stage. The"full-length"reinforcement arrangement leads to a higher peak structural collapse resistance under catenary mechanism and an earlier entry into catenary tension stage.
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