Design of steel structures under fire conditions

Abstract

Changes 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.

Investigation of the Strength of Steel Structures as a result of Fire in Different Floors

“…Çelik yapıların yangın güvenliğinde çelik kesit tipini açıklamak için "Yangına dayanıklı çelikler (FRS)" ismi kullanılır [12]. Temelde termo-mekanik bir biçimde işlenen çelik sıradan yapısal çeliklerden yapısal bir biçimde yangında çok daha iyi performans sağlar.…”

Best practices for reducing the potential for progressive collapse in buildings

“…It must be understood that this test method is not intended to represent realistic conditions, but is a standard protocol for comparing relative performance of different systems. With advances in fire science and advanced structural analysis as a design tool, it is becoming possible to consider realistic fire scenarios and fire effects on the system as a whole as part of the structural design process (Kruppa 2000;Bennetts and Thomas 2002;SFPE 2002;AISC 2005a). The new approach of performance-based engineering, where there is a strong motivation to seek alternatives to design by qualification testing, will move the structural engineering profession in this direction in fire safety assurance.…”

Designing buildings for fire safety: a risk perspective

“…The fire-resistance level specified for members should also reflect the nature of 'failure' and associated consequences. For example, it is known [10] that floor systems incorporating steel beams with little or no protection will, when exposed to fire, gradually deform and resist the applied loads through membrane action, giving a performance that is considerably better than might be expected from isolated member behaviour. The impact of such deformation on supporting columns may be significant, and needs to be considered.…”