Lateral displacement and collapse of single-story steel frames in uncontrolled fires
Lateral displacement and collapse of single-story steel frames in uncontrolled fires
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DOI：
10.1016/j.engstruct.2003.12.007
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发表时间：
2004-04
影响因子：
5.5
通讯作者：
H. Ali;P. E. Senseny;R. L. Alpert
中科院分区：
文献类型：
--
作者：
H. Ali;P. E. Senseny;R. L. Alpert
在工业和商业单层钢框架建筑中，在大型失控火灾中无保护框架的倒塌模式和侧向位移部分地影响防火墙的完整性。在这项研究中，完整的变形序列的框架，从最初的热膨胀，其次是柱屈曲或形成塑性铰的梁，倒塌被用来确定所需的安全间隙之间的框架和防火墙，允许框架横向扩展，而不接触和损坏墙壁。使用ABAQUS开发了一个经过实验验证的非线性有限元模型，以模拟框架的热传递及其随后的热膨胀和塌陷。几何和温度相关的材料非线性和蠕变都包括在分析中。单层裸钢框架的倒塌模式取决于火灾场景，当火灾发生在靠近墙壁的地方时，可能会朝向防火墙，或者在更理想的模式下远离墙壁。随着火灾空间范围的增大，框架的侧向位移也随之增大。屋顶重量越大，破坏发生得越快，框架和防火墙之间的最小间隙越小。在分析中包括蠕变的重要性随着屋顶荷载和柱的增高而增加。高温下钢材机械性能的不稳定性会影响框架的预期性能，从而影响防火墙的安全性。
In industrial and commercial single-story steel-framed buildings, the collapse mode and lateral displacement of unprotected frames in large uncontrolled fires affect in part the integrity of firewalls. In this study, the complete deformation sequence of frames, from initial thermal expansion, followed by either column buckling or formation of plastic hinges in the beams, to collapse was used to determine the safe clearance required between the frame and the firewall to allow the frame to expand laterally without contacting and damaging the wall. An experimentally validated nonlinear finite element model, using ABAQUS, was developed to simulate the heat transfer to the frame and its subsequent thermal expansion and collapse. Both geometric and temperature-dependent material nonlinearities and creep were included in the analysis. The collapse mode of single-story bare steel frames depends on the fire scenario and could be toward the firewall when fire is localized close to the wall or in the more desired mode away from the wall. Lateral displacement of frames increases with the increase of spatial extent of fire. The greater the roof weight, the sooner the failure will occur and the smaller is the minimum clearance between frames and firewalls. The importance of including creep in analysis increases with higher roof loads and taller columns. Uncertainties in the steel mechanical properties at high temperatures affect the predicted performance of frames and hence the safety of firewalls.