Design of steel structures under fire conditions

Abstract

AbstractChanges have occurred internationally in regulations for fire safety in buildings, and there has been significant recent progress towards rational design for fire safety in buildings. Possible design objectives for fire safety are listed and the interacting factors that influence fire safety in buildings are discussed. A factor of particular importance is fire growth and development, with recent developments in this area leading to increased recognition of non‐uniform conditions occurring in many enclosures of practical significance in fire safety design. Coroner's records and fire statistics have been used to improve our understanding of the factors that lead to casualties (particularly fatalities) in fires, and these have shown that the structure is rarely a factor.Recent progress in understanding and modelling the behaviour of steel structures in fires is reviewed. Recent testing for modern structural steels has resulted in new data for thermal expansion and stress‐related and creep strain, with new mathematical relationships for strain that can easily be used in computer models. Studies of the response of steel columns and composite beams are reviewed, including studies of the effect of temperature gradients and axial restraint on column performance, the development of a simplified equation for concrete‐filled tubular column behaviour and lateral buckling of beams. A major area of recent research is the behaviour in fire of significant parts of a building structure (rather than individual members), particularly in response to the Cardington eight storey steel‐framed building tests. Several recently published approaches to modelling overall structural behaviour are reviewed in the light of these tests.