A Review on Structural Fire Tests of Two-Way Composite Floors

The utilisation of composite floor systems in modern construction allows for building large floor areas with efficient use of material and labour. The efficiency of this flooring system in carrying ambient loads as well as the thermal thinness of its steel framing makes it hypothetically sensitive to fire loads as a small exposure time may result in a rapid increase in temperature. However, a series of fire events and then large-scale experiments at the turn of the century demonstrated that composite floors could display surprising robustness in the face of high temperatures. Soon after, the total collapse of the World Trade Center towers 1, 2 and 7 showed the opposite. For the two decades since then, a large amount of experimental and theoretical work has been performed on this topic. This review aims to formulate an understanding of the thermo-mechanical behaviour of composite floors in fire, and to leverage that understanding to design more efficient and more robust buildings. We first surveyed the literature, and then summarized the composite floors being studied into three categories: isolated composite slab panels, composite floor assemblies, and large-scale tests. Then, theoretical design and analysis methods are discussed in light of the reviewed literature. Finally, this review coalesces the knowledge generated from the literature and lists the remaining challenges in the area, and set out a set of recommendations for designing composite floor systems for fire.