压型钢板-组合楼板耐火试验和破坏模式的探讨

在标准升温条件下,对闭口式压型钢板组合楼板进行了耐火试验,并测试了不同部位的升温情况。试验表明,被混凝土包裹的部分升温要比直接受火面慢,但由于热传导,升温122MIN时被混凝土包裹的部分最低温度也超过了600℃;无论是火灾前期还是后期,板的混凝土厚度都是影响组合楼板耐火性能的重要参数。在此基础上,分析了高温状态下组合楼板的试验现象,定性地分析了各影响参数,并探讨了组合楼板在耐火极限状态下的破坏模式。由于影响组合楼板耐火性能的参数多而复杂,因此,建议防火设计时必须保证一定的混凝土厚度,确保火灾下组合楼板的安全。

FIREPROOFING TEST AND DISTRUCTIVE MODE OF COLD-FORMED STEEL DECK-COMPOSITE SLAB

It is tested that the elevated temperatures on different parts of cold-formed steel deck with closed rib under the standard elevated temperature condition. The results indicate that the elevated temperature on the part enwrapped in concrete is slower than that of a direct fire, but because of heat conduction, the lowest temperature of this part can also exceed 600℃ after fired for 122 minutes. The results prove that the thickness of concrete is one of the important factors that influences the fireproofing properties of the composite slab during the initial period of a fire or later. It was analyzed the phenomenon of composite slab under high temperature condition and was qualitatively analyzed the factors that influence fireproofing properties and also discussed the destructive mode of composite slab under critical fireproofing condition. Because the factors are too many and complicated, under this condition, it is proposed that the safety of a composite slab during fire should be guaranteed through a certain thickness of concrete.