边柱拆除时预压装配式PC框架抗连续倒塌性能试验研究

Experimental study on progressive collapse resistance of preloaded fabricated PC frame with the demolition of side columns

为研究预压装配式预应力混凝土(prestressed concrete,PC)框架的抗连续倒塌能力,文章设计1榀2层2跨预压装配式PC平面框架进行底层边柱柱拆除试验,对其裂缝发展、变形能力、破坏模式进行探究。研究表明,预压装配式PC框架在边柱失效的情况下具有较好的抗连续倒塌能力。在试验加载过程中,框架的混凝土裂缝开展与破坏集中在边柱失效跨内两侧梁端与框架柱牛腿结合部,框架柱以及远离失效边柱的框架梁基本完好。在倒塌阶段时,框架内部的预应力钢绞线产生的轴向拉力为结构提供了较大的承载力;普通钢筋由于在梁柱结合处未贯通,因此并未受拉屈服,贡献的承载力较小,但对抑制框架梁裂缝的开展具有一定的作用。

In order to study the progressive collapse resistance of preloaded fabricated prestressed concrete(PC)frame,a two-story and two-span preloaded fabricated PC plane frame is designed for the demolition test of bottom side columns,and its crack development,deformation capacity and failure mode are explored.The results indicate that the preloaded fabricated PC frame have good capacity of resisting progressive collapse with the failure of side columns.The development and destruction of concrete cracks in the frame concentrate on the joint between the ends of both side beams and the brackets of the frame columns in the failure span of the side columns during loading.The frame columns and the frame beams far away from the failed side columns are undamaged.The axial tension produced by the prestressed steel strands inside the frame provides a large bearing capacity for the structure during the collapse stage.Non-prestressed reinforcement without tension yield contributes little to the bearing capacity at collapse stage,but it effectively inhibits the formation and development of cracks in beam.