Behavior of Composite Slim Floor Structures in Fire
Behavior of Composite Slim Floor Structures in Fire
复制标题
DOI：
10.1061/(asce)0733-9445(2000)126:7(830
复制
发表时间：
2000-07
期刊：
影响因子：
--
通讯作者：
Zhongcheng Ma;P. Mäkeläinen
中科院分区：
文献类型：
--
作者：
Zhongcheng Ma;P. Mäkeläinen
近年来，整个欧洲对开发和设计钢框架建筑中的薄地板系统越来越感兴趣。本文用数值分析方法研究了组合不对称薄楼板梁作为隔震构件和框架的一部分的抗火性能。研究了三种方案，包括隔震梁、半刚性梁柱连接的平面子框架和三维薄楼板框架体系。第一个方案旨在根据标准的火灾测试方法来探索梁的耐火性能。第二种方案的目的是揭示框架的连续性对细长楼板梁抗火性能的影响以及框架单元之间的力学相互作用。第三个方案是初步识别组合板对梁在火灾中的性能的影响。研究表明，当荷载比为<；0.5时，隔震薄楼板梁在不增加任何防火措施的情况下具有60min的标准耐火能力。作为框架的一部分，即使梁的底部钢翼缘温度达到9007℃(90分钟ISO火灾暴露)，梁仍保持其稳定性。分析结果表明，在ISO加热的早期阶段，周围部件提供的轴向约束导致梁的变形较大，此后梁的行为较为稳定。旋转约束在本质上引起了火灾荷载比的变化，可以用本文提出的“修正荷载比”来量化。
In recent years, increasing interest has been shown throughout Europe in developing and designing slim floor systems in steel-framed buildings. This paper presents the fire resistance behavior of the composite asymmetric slim floor beam as an isolated member and as a part of the frame using numerical analysis methods. Three schemes were investigated, including isolated beams, a plane subframe with semirigid beam-to-column connections, and a 3D slim floor frame system. The first scheme aimed to explore the fire resistance of the beams according to standard fire-testing methodology. The objective of the second scheme was to reveal the effect of frame continuity on the fire resistance of the slim floor beam and the mechanical interaction between the frame elements. The third scheme was to preliminarily identify the influence of the composite slab on the beam behavior in fire. The investigations show that the isolated slim floor beam has a 60-min standard fire resistance without any additional fire protection, if the load ratio is <0.5. As a part of the frame, the beam still keeps its stability even when the temperature of the bottom steel flange of the beam reaches up to 900 7C (90- min ISO fire exposure). The analyzed results indicate that the axial restraints provided by the surrounding parts cause a larger deformation of the beam in the earlier ISO heating phase and a more stable behavior thereafter. The rotational restraints essentially cause the change in the applied load ratio in fire, which can be quantified using the ''modified load ratio'' proposed in this paper.