Fire Resistance of Steel Floors Constructed with Experimental Fire Resistant Steels

Abstract

This chapter reports a continuation of research on the modeling of the fire resistance of steel floor structures, using available computer software. Modeling of the heat transfer in steel sections and the moment resistance for floor structures has been made. The moment capacity software is used to calculate the fire resistance of I-beam, slimflor beam, and asymmetric slimflor beam floor structures, constructed with three types of steel with different strength characteristics. Strength reduction factors at 2% strain are used in calculating beam moment capacity at fire condition. The chapter follows a previous investigation that used the software to obtain the moment capacity of beams constructed with Nippon Steel fire resistant steels and then calculated the fire resistance. It is found that the use of fire resistant steels can increase the fire resistance of conventional floor structures by nearly half an hour, but the improvement in slim floors is limited to less than 20 minutes. None of the fire resistant steels could achieve 30 minutes fire resistance in conventional non-composite and composite floors without protection.