火灾中外伸端板节点的弹簧模型和试验研究

Experimental Study and Spring-Component Modelling of Extended End-Plate Joints in Fire

为得到外伸端板节点的抗火性能,采用火灾试验炉对4个足尺H型钢进行了火灾行为的研究。从试验中得到了外伸端板节点试件的破坏特征和破坏模式。通过比较有无加劲肋以及不同厚度的端板的节点的抗火能力,分析了加劲肋和端板厚度对节点抗火能力的影响。此外,还描述了弹簧模型,用于预测外伸端板钢节点在高温下的性能。节点构成被认为由预先设定力学性能的弹簧构成,例如,刚度和强度。高温下的节点响应可以通过汇集构成、刚度和强度来预测,而刚度和强度的下降由中国现行的钢结构火灾安全技术规范建议的升温过程来设定。结果表明,模型计算结果与试验数据很吻合。

In order to investigate the fire-resistant capacity of extended end-plate joints, an experimental study was performed by using a furnace on four full-scale specimens made with H-shaped steel. The failure characteristics and failure modes of the extended end-plate joint specimens in fire were obtained from the experiment. The influence of rib stiffeners and depth of end-plates on fire-resistant capacity of the joints was found by comparing the capacity of the joints with and without rib stiffeners and different depths of end-plate. In addition, this paper also describes a springcomponent model employed for predicting the behaviour of extended endplate bare-steel joints at elevated temperature. The components of a joint are considered to consist of spring components with predefined mechanical properties, i.e. stiffness and strength. The response of the joints subjected to elevated temperature can be predicted by assembling components, the stiffness and strength of which are assumed to degrade with increasing temperatures based on the recommendations presented in the Chinese Technical Code on Fire Safety of Steel Building Structure. It is demonstrated that the results from the model agree with experimental data quite well.