钢结构火灾反应相似模型及试验研究与分析

EXPERIMENTAL RESEARCH AND ANALYSIS ON SIMILARITY MODEL FOR STEEL STRUCTURES UNDER FIRE

为采用缩尺模型研究火灾下整体钢结构的火灾反应,首先基于火场相似关系以及热传导分析理论推导了钢结构火灾反应相似关系模型,其次根据建立的火场与结构相似关系模型分别设计了1/4和1/8缩尺火场试验模型与钢框架结构试验模型,并对其进行了缩尺火灾试验研究,对比分析了空气温度、结构温度、结构变形与结构破坏规律。结果表明:烟气温度、结构温度、结构变形表明结构火灾反应相似模型具有较好的合理性和准确性,承载力与稳定性也满足相似模型;温度相似比为1以及相同的火场和结构时间相似比可以简化相似模型;缩尺模型试验需要严格控制火场维护结构的变形以及外界通风条件,才能保证结构在高温破坏阶段后的相似性。

In order to analyze the fire response of a whole structure under fire using the method of scaled fire model,a similarity relation model for fire response of steel structures under fire was firstly developed in this paper based on the fire similarity and heat conduction theory.Then 1/4 and 1/8 scale fire test models and test specimens of steel frame structures were designed according to the relationships,and experimental studies were performed.Finally,comparative analysis of air temperatures,structure temperatures,structure deformation and structure failure was carried out.The results show that the similarity model is reasonable and accurate,and the bearing capacity and stability also meet the similarity model.The similarity model can be simplified by assuming the temperature similarity ratio of 1 or assuming the same similarity ratio of fire and structural time.The deformation of the maintenance structures and the external ventilation conditions should be strictly controlled in the scale fire tests,so as to ensure the similarity of the structure under high temperature during the post-failure stage.