Fire Resistance of Steel-Framed Multi-Storey Buildings

Abstract

This chapter provides a brief description of the developments in the fire resistance of steel framed multistory buildings, specifically the investigations undertaken at the UK's Building Research Establishment. It discusses that temperature in unprotected steel elements of a building rise rapidly under fire conditions. These increases in steel temperatures are accompanied by sharp reductions in strength and stiffness. Consequently, regulatory authorities require fire protection to structural steel elements to achieve a required fire resistance with the intention of ensuring the stability of the steel structures under fire conditions. The design of steel frames in multistory buildings for fire resistance is moving away from the traditional prescriptive method of fulfilling the requirements of building regulations to being performance based, i.e., based on the understanding of the fire behavior, the structural behavior, and requirement under fire conditions. Fire protection to steel beams in most multistory steel framed buildings may be eliminated. The reason is that the floor slabs have inherently sufficient load carrying capacities via the mechanism of tensile membrane action at large deflections.