Structural behaviour in fire compartment under different heating regimes-Part 1 (Slab thermal gradients)

Modelling the full-scale Fire Tests at Cardington has led to new understanding of the behaviour of structures under fire conditions. Much of this understanding has come from parametric explorations using models verified against the tests. The structural phenomena observed in highly redundant, composite structures, during a compartment fire are dominated by restrained thermal expansion. The large deflections experienced in the structural elements in the region of the fire are almost entirely attributable to thermally induced strains. The mechanisms responsible for producing these large deflections are restrained thermal expansion and thermal bowing. Material degradation and loading are secondary influences. A clear understanding of the response of the structure to an average temperature increase and through depth temperature gradients is essential. This paper discusses the structural response when subjected to different heating regimes obtained by changing the mean temperature and temperature gradient applied in the concrete slab of the composite floor slab system to a computer model of the British Steel restrained beam test.