【摘要】 为了解超高层建筑发生火灾后变形特征及失稳后的非连续坍塌过程,掌握引起变形和坍塌的原因,将三维颗粒流软件(PFC3D)作为模拟平台,设置核心筒-框架结构的超高层建筑火灾区域,并模拟坍塌过程。在考虑钢筋和混凝土共同作用结果的基础上,提出火灾区域中构件属性设置方法及模拟步骤。分析得到造成建筑结构摆动的3种原因,一是火区位置不同导致上部结构对火区的压力不同,二是火区位置不同导致结构受到的约束不同,三是受热膨胀性使构件产生不同程度变形。结果表明:燃烧温度为500℃,3 h后建筑发生摆动,表现出对火区位置和燃烧时间敏感的特征。1 000℃下1 h内,建筑物首先发生破坏的是梁构件,然后是承重柱。即建筑一旦进入结构破坏阶段,坍塌将是迅速且不可逆的。更多还原

【Abstract】 In order to understand the fire-caused high-rise building deformation features and the discontinuity collapse process stability,and the reasons for the deformation and collapse,PFC3 Dwas used as the simulation platform. The high-rise building is a frame-core tube structure. The fire areas in the building are set. The discontinuity collapse process caused by fire was simulated. Considering the results of interaction between steel and concrete,the component attribute setting method and steps of simulation were put forward. Three kinds of causes were identified for building swing. The first is the pressure from the upper building is different in different fire positions. The second is the constrains of structure are different in different fire positions. The third is the heat-caused expansion of structure is different in different fire positions. Simulation results show that at 500 ℃,after 3 hours,the building begins to oscillate,that the oscillation is sensitive to the fire area position and burning time,that at 1 000 ℃,in 3 hours,the beams of building are destroyed firstly,and then the load-bearing column,and that once the building enters the structure failure stage,collapse will be rapid and irreversible.更多还原