防火板保护钢柱四面受火时截面温度计算方法  

An Approach for Predicting Cross-Sectional Temperatures of Four-Side Fire Exposed Steel Columns Protected by Insulation Board

作　　者：王培军[1] 夏金环[1] 郑玉超[1] 

机构地区：[1]山东大学土建与水利学院,济南250061

出　　处：《建筑钢结构进展》2015年第2期44-51,共8页Progress in Steel Building Structures

摘　　要：研究了采用防火板保护钢柱四面受火时的截面温度计算方法,分别考虑了防火板与钢柱无间隙及防火板与钢柱有间隙两种情况。由于采用防火板保护时,钢构件与防火保护层内表面之间主要通过热辐射进行热量传递,与现行欧洲规范(EC 3)公式假定构件防火保护层之间通过热传导进行热量传递不同。现行EC 3规范公式能较为准确地计算热传导系数较小的防火涂料保护时构件升温,但不能准确计算火灾下热传导系数较大的防火薄型板保护钢柱的温度。通过在现行规范公式中增加空气的热阻一项,以考虑热辐射传热方式对构件截面升温的影响。分别采用有限元方法和建议公式,对防火薄型板保护,不同保护层厚度和不同截面系数钢柱截面升温规律进行分析,结果表明修正公式的计算结果与有限元结果吻合良好。This paper presents an approach for predicting cross-sectional temperatures of four-side fire exposed steel columns protected by fire insulation board.Two types of fire protection methods are studied：1）no gap between fire board and steel column;2）agap between fire board and steel column.Current design equations in EC3 are not applicable for those columns protected by thin fire insulation board with relatively higher conductivity.Heat transfer is mainly in a form of radiation passing through fire insulation board,which is different from a sprayed fire protection where heat conduction is a dominate heat transfer format.A simplified model is presented to analyze the thermal response of steel columns protected by thin fire insulation board exposed to standard fire from four sides.Modification on current EC3 design equation is also proposed by incorporating thermal resistance of hot smoke.The temperature prediction from proposed equations agrees well with the data obtained from finite element analysis.

关 键 词：传热系数 防火板 四面受火 温度计算 

分 类 号：TU352.5[建筑科学—结构工程]