【摘要】 通过已有试验结果对火灾下考虑薄膜效应的楼板极限承载力计算方法进行了验证,证明了提出的计算方法的可靠性。根据楼板的薄膜效应分析模型,分析了温度、楼板长短边比例、配筋分布和挠度等参数对楼板极限承载力的影响。分析表明,楼板挠度越大,楼板的长跨比越小,长跨与短跨配筋率的比值越小,楼板在火灾下产生的薄膜效应就越明显,对楼板火灾下的极限承载力提高就越大。根据考虑薄膜效应计算楼板极限承载力的理论方法,提出了对无防火保护的楼板(包括次梁)进行抗火设计验算的简化实用方法,在满足1.5h耐火时间楼板不坍塌的条件下,可减小楼板及次梁的防火成本。本方法可供工程设计人员在进行楼盖的抗火设计时参考。更多还原

【Abstract】 The method of calculating the ultimate load bearing capacity of slabs with considering the effect of membrane action is validated by experimental results.Based on the model of membrane action in a floor slab subjected to fire,the effects of temperature,the ratio of long span to short span,distribution of reinforcement on the limited bearing capacity of the slab are studied.It is shown that after membrane action,the larger the deflection of the slab is,the smaller the ratio of long span to short span is,or the smaller the ratio of reinforcement of long span to that of short span is,the stronger the membrane action is.According to the theoretical method of calculating the limited bearing capacity of slab with the effect of membrane action,a simplified and practical method is proposed.Finally an example of an unprotected floor slab is given.更多还原