火灾下钢筋混凝土板保护层厚度的选取  

Optimization of thickness of protecting cover for reinforced concrete slabs in fire

作　　者：郝淑英[1] 刘秀英[2] 张琪昌[2] 

机构地区：[1]天津理工大学机械工程学院,天津300191 [2]天津大学力学系,天津300072

出　　处：《武汉大学学报（工学版）》2007年第6期76-79,共4页Engineering Journal of Wuhan University

基　　金：天津市高校科技发展基金(编号:20040505);火灾科学国家重点实验室基金(编号:HZ2005-KF05)资助项目

摘　　要：采用理论分析与有限元分析相结合的方法，研究了火灾下三跨连续钢筋混凝土板保护层厚度对楼板刚度、极限抗弯承载力及耐火能力的影响，发现：（1）保护层厚度的增加一方面降低了楼板的有效高度，引起极限抗弯承载力及刚度的降低；但同时也降低了钢筋的升温速度，减缓了钢筋强度、刚度退化的速度．综合考虑保护层厚度的影响，建议保护层厚度取值20～25mm．（2）适当地增加截面的高度可有效地提高连续板的耐火极限．The effects of protecting cover thickness on ultimate bending moment, stiffness and fire resistance of three spans continuous reinforced concrete slab in fire have been investigated by theory and finite element method. It is showed that： （1） the effective height of the slab is reduced with the increase of protecting cover thickness; the stiffness and ultimate bending moment of slab are also decreased; meanwhile, the temperature increasing velocity of reinforement bar is descreased; it results in lower strength and stiffness reduced ratio and better fire resistance. The optimal cover protecting thickness of 20--25 mm is put forward; （2） The appropriate section height can effectively improve fire resistance of slab.

关 键 词：火灾 保护层 钢筋混凝土板 极限承载力 

分 类 号：TU3[建筑科学—结构工程]