Mechanism analysis of fire behavior of concrete slabs subject to uni-axial (bi-axial) in-plane restraint
Wang Yong1,2 Ma Shuai1 Shi Weinan1 Zhanng Yajun1 Duan Yakun1 Yuan Guanglin1,3
1. Jiangsu Key Laboratory of Environmental Impact and Structural Safety in Engineering, China University of Mining & Technology, Xuzhou 221008, China; 2. State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining & Technology, Xuzhou 221008, China; 3. JiangSu Collaborative Innovation Center for Building Energy Saving and Construct Technology, Xuzhou 221008, China
Abstract：To investigate the effect of the in-plane restraint on the fire behavior of concrete slabs, the numerical analysis of eight in-plane restrained concrete slabs were conducted. The influence of the geometrical nonlinearity (linearity) and concrete thermal strains on the deflection, bending distribution and membrane actions were investigated. Meanwhile, the parametrical analysis was conducted to investigate the effect of the restraint type, restraint level, aspect ratio, reinforcement ratio and thickness on the temperature, deflection, failure mode and fire resistance of the restrained slabs. The research results indicate that for any restraint condition, larger concrete thermal strains result in larger deflections of the restrained slabs, and the geometrical nonlinearity should be considered in the numerical analysis. In addition, the in-plane restraint will lead to lower mid-span moments and larger negative moments, which is not beneficial to the tensile membrane action development of concrete slabs at large deflections. Fire behavior of the restrained slabs are dependent on the interaction of restraint types, restraint level and aspect ratio. It is beneficial to enhance the fire resistant performance of the restrained slabs by increasing the slabs thickness and the reinforcement ratio.
