摘要
为了较准确地评估火灾条件下三面受火工字钢截面的温度分布,采用非稳态的热传导计算理论对工字钢上下翼缘与腹板进行分区,分别计算了钢构件截面各部分的温度场,综合考虑表面热阻、背火面的热损失,较精确地分析出截面各部分温度场分布。计算结果表明:钢构件各部分截面温度呈极不均匀分布,受标准火60min和120min时,上翼缘比截面平均温度低约57%和64%;下翼缘比截面平均温度高约13%和20%;而腹板比截面平均温度高约88%。钢结构截面各部分温差较大将会引发较大的温度应力,更高的腹板温度可能引发腹板率先破坏,在确定构件保护层厚度时应予充分重视。
In order to assess the temperature distribution of I- shaped steel member exposed to fire on three sides in an accurate way, the I-shaped section is divided into three zones,the upper and lower flange and the web plate. Based on the theory of unsteady heat transfer, the temperature distribution of three zones of the I-shaped is calculated on the premise of considering the heat loss from the top flange to the concrete plate and thermal-resistance of the protective coating surface. The results indicate that the temperature distribution within the whole section is not very uniform. When the steel members exposed to the standard fire 60 or 120 minutes , the temperature of upper flange is 57% and 64% lower than the average temperature of the whole section respectively, while the temperature of lower flange is 13% and 20% higher than the average respectively, the temperature of web plate is 88% higher than the average. The temperature differences in the whole section will definitely lead to the higher thermal stress,the higher temperature of the web plate makes it more possible to yield, which should be considered in determining the protective coating of steel member.
出处
《消防科学与技术》
CAS
北大核心
2009年第4期158-161,共4页
Fire Science and Technology
基金
国家重点基础研究专项经费资助项目(2001CB40960308)
关键词
钢构件
温度分区
温差
温度应力
steel member
zone-area calculation method
temperature difference
thermal stress
