复杂高层钢结构抗连续倒塌能力分析关键技术研究

基于拆除构件法，通过显式动力有限元分析，对复杂高层钢结构待拆构件的选择、构件失效的模拟方法以及构件损伤评价标准的制定等关键技术进行了研究。结果表明：对于高层钢结构，竖向构件的敏感性可基本反映待拆构件的重要性，水平构件的敏感性可反映剩余结构发挥抗倒塌机制的储备大小。此外，还建立了基于美国性能化设计评估方法FEMA 356纤维模型的构件失效模拟方法，可使构件在动力响应过程中的失效破坏既满足FEMA 356构件变形极限又满足材料应变极限，同时还可依据FEMA 356中的构件性能水准与微观应变的对应关系评价剩余结构构件的损伤程度。运用该方法对案例工程钢结构的抗连续倒塌能力进行分析，结果表明：关键构件拆除后，结构未发生连续性倒塌，剩余结构能够形成有效的承载替代路径；大部分构件的塑性转角未达到IO水准，发生较大塑性变形的构件主要集中在替代路径的承载构件上。

Study on key issues of progressive collapse resistance capacity analysis for complex high-rise steel structure

Based on the alternate path method and explicit dynamic finite element method,the key issues as the selection method of removal component, the failure simulation method of components and the setting of damage evaluation criteria of progressive collapse resistance capacity analysis for complex high-rise steel structure were studied in this research. The analysis results show that the importance of removal components can be evaluated by the sensitivity index of vertical components of the high-rise steel structure, and the progressive collapse resistance capacity of remained structure can be evaluated by the sensitivity index of horizontal components. In addition, a new simulating method of component failure using fiber model was proposed based on the generalized force-deformation relation for steel components of FEMA 356. This method can not only match the component deformation limit of FEMA 356 but also meet the maximum strain limit of material; damage of the remaining components can also be evaluated by the relation between the FEMA 356 performance level and microscopic material strain according to this method. Using this method, the progressive collapse resistance capacity of the steel structure of the case project was analyzed, and the results show that: progressive collapse does not appear after the key component is removed, and the remaining structure can form an effective alternative path; plastic hinge of most components do not reach the immediate occupancy performance level, and the components with large plastic deformation are mainly concentrated on the components in alternative paths.