Performance based approach for evaluating fire resistance of prestressed concrete hollowcore slabs

摘要

Prestressed concrete (PC) hollowcore slabs are widely used in building applications due to numerous advantages they offer over other floor systems. Building codes generally specify fire resistance ratings for these hollowcore slabs, since structural fire safety is one of the primary considerations in buildings. Currently, fire resistance of concrete slabs is assessed based on standard fire tests, or prescriptive methods wherein fire resistance is tabulated in terms of slab thickness and concrete cover thickness to reinforcement. These prescriptive approaches do not yield realistic fire resistance, since many of the critical factors that influence fire resistance of hollowcore slabs are not taken into account. In this paper, a performance-based methodology is applied to evaluate the fire resistance of PC hollowcore slabs under realistic fire, loading and restraint scenarios. The steps involved in undertaking performance-based fire design are outlined and their applicability to a design situation is illustrated through a case study. Results from numerical studies are presented to demonstrate the application of performance based method for enhancing fire resistance of PC hollowcore slabs.