角柱失效下钢管混凝土柱-组合梁框架抗连续倒塌能力研究

RESEARCH ON PROGRESSIVE COLLAPSE RESISTANCE CAPACITY OF COMPOSITE FRAME WITH CFST COLUMNS UNDER CORNER COLUMN REMOVAL SCENARIO

  • 摘要: 为研究角柱失效工况下钢管混凝土组合框架的抗连续倒塌性能,该文设计了1/4缩尺比例的两层两跨钢管混凝土柱-组合梁平面框架试件,对拆除角柱构件的剩余结构进行单调静力加载,获得该类结构的荷载-位移关系曲线、整体/局部破坏模式以及构件关键部位的应变曲线;在此基础上,采用能量等效原理分析该类结构的倒塌等效动力效应,并对该类结构的抗倒塌能力进行简要评估。研究结果表明:角柱失效工况下,钢管混凝土柱-组合梁框架受力过程主要经历了四个阶段:弹性阶段、弹塑性阶段、内力重分布阶段和破坏阶段;试件整体破坏主要集中于失效跨,破坏特征主要以钢梁断裂和扭曲变形为主,且二层钢梁先于一层钢梁发生破坏;压型钢板组合板受力过程中与钢梁发生局部分离,部分栓钉拔断;失效跨二层钢梁翼缘开裂时,框架内力通过相邻柱向一层钢梁传递。基于试验结果和能量平衡原理的结构动力响应简化评估方法,发现角柱失效工况下该类结构仍具有15.3%的抗连续倒塌剩余能力。

     

    Abstract: To study the progressive collapse performance of the composite frame with CFST columns under the corner column removal scenario, a 1/4-scale two-story-two-bay composite frame specimen was designed and tested. By the monotonic static loading of the residual structure after the corner column was damaged, the tests obtained the load-displacement relationship curves of the composite frame, the global/local failure modes of the structure and the strain developments of critical locations. The energy equivalence principle was used to analyze the progressive collapse dynamic effects. The resistance to progressive collapse of the composite CFST frame was evaluated. The experimental results show that the progressive collapse loading process of composite frame with CFST columns mainly includes four stages in the corner column removal scenario, i.e., elastic stage, elastic-plastic stage, internal force redistribution stage and damage stage. The damage of the specimen is mainly concentrated in the failure span. The failure characteristics are mainly on the fracture and distortion of steel beams, and the steel beams on the second floor are damaged before that on the first floor. It is also found that the composite slabs with profiled sheeting and concrete are separated from the steel beam and the shear studs are pulled off. When the flange of the steel beam on the second-floor is cracked, the internal force is transferred to the first-floor steel beam through the adjacent column. Based on the test results and the energy equivalence principle, it is found that the composite frame has 15.3% residual capacity to resist the progressive collapse in the corner column removal scenario.

     

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