Progressive collapse analysis of steel structures under fire conditions
Progressive collapse analysis of steel structures under fire conditions
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DOI：
10.1016/j.engstruct.2011.10.009
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发表时间：
2012
影响因子：
5.5
通讯作者：
Ruirui Sun;Zhaohui Huang;I. Burgess
中科院分区：
文献类型：
--
作者：
Ruirui Sun;Zhaohui Huang;I. Burgess
本文提出了一种鲁棒的静态-动态过程。该开发扩展了Vulcan软件的能力，以模拟钢结构在火灾条件下局部和整体渐进倒塌期间的动态和静态行为。动态过程采用显式积分法。这个模型可以用来允许结构分析继续超越暂时的不稳定，这将导致奇点在完整的静态分析。静态和动态分析之间的自动切换使Vulcan成为研究构件局部失效所产生的结构渐进倒塌机制的有力工具。该程序在几个实际案例中得到了验证。本文还对火灾条件下柱破坏引起的钢框架倒塌机理进行了初步研究。结果表明，对于无支撑框架，较低的荷载比和较大的梁截面会产生较高的破坏温度，从而导致结构整体倒塌。然而，较高的荷载比和较小的梁截面更容易产生框架的局部倒塌。支撑系统有助于防止框架逐渐倒塌。框架侧移刚度越高，破坏柱在重稳位置的竖向变形越小。然而，框架的整体破坏温度对框架的侧移刚度不敏感。
In this paper a robust static-dynamic procedure has been developed. The development extends the capability of the Vulcan software to model the dynamic and static behaviour of steel buildings during both local and global progressive collapse of the structures under fire conditions. The explicit integration method was adopted in the dynamic procedure. This model can be utilized to allow a structural analysis to continue beyond the temporary instabilities which would cause singularities in the full static analyses. The automatic switch between static and dynamic analysis makes the Vulcan a powerful tool to investigate the mechanism of the progressive collapse of the structures generated by the local failure of components. The procedure was validated against several practical cases. Some preliminary studies of the collapse mechanism of steel frame due to columns’ failure under fire conditions are also presented. It is concluded that for un-braced frame the lower loading ratio and bigger beam section can give higher failure temperature in which the global structural collapse happens. However, the localised collapse of the frame with the higher loading ratio and smaller beam section can more easily be generated. The bracing system is helpful to prevent the frame from progressive collapse. The higher lateral stiffness of the frame can generate the smaller vertical deformation of the failed column at the re-stable position. However, the global failure temperature of the frame is not sensitive to the lateral stiffness of the frame.