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研究了支撑布置对火灾下钢框架结构抗连续性倒塌性能的影响。考虑水平和竖向两种支撑布置形式,前者沿水平向布置在结构顶部,后者布置在结构各楼层,分别考虑其布置在结构边缘或者内部的情况。应用OpenSees软件对某7跨8层平面钢框架结构模型进行了数值分析。结果表明,火灾下结构倒塌始于受火柱的屈曲,该局部破坏向周边传播,导致整体结构下沉式倒塌或侧向倾覆式倒塌。竖向支撑可有效抑制结构的侧向倒塌,但容易导致底层柱的依次屈曲,不建议单独使用;通过将竖向支撑布置在结构内部,可有效阻止破坏向周边结构传播;水平支撑通过平均分配各柱轴压力,有效抑制周边柱的压曲,但容易造成结构局部或是整体侧向倒塌;同时应用两种支撑可有效提高结构抗倒塌性能。
The influence of bracing arrangement on the anti-continuous collapse performance of steel frame structure under fire was studied. Two horizontal and vertical support arrangements are considered, the former being arranged horizontally at the top of the structure, the latter being arranged at each floor of the structure, taking into account their placement at the edge or the inside of the structure, respectively. The numerical analysis of a 7-span, 8-story, planar steel frame structure model was conducted using OpenSees software. The results show that the structure collapse under fire starts from the buckling of the fire column and the local damage spreads to the periphery, resulting in the collapse of the whole structure or the collapse of the lateral overturning structure. Vertical support can effectively inhibit the lateral collapse of the structure, but easily lead to the underlying column buckling, not recommended for use alone; by placing the vertical support within the structure can effectively prevent the spread of damage to the surrounding structure; horizontal support by the average distribution The axial pressure of each column can effectively suppress the buckling of the surrounding columns, but it is easy to cause partial or total lateral collapse of the structure. Simultaneously, the application of two kinds of supports can effectively improve the structural collapse resistance.