Fire Safe Design - A New Approach to Multi-Storey Steel Framed Buildings


Large-scale fire tests conducted in a number of countries and observations of actual building fires have shown that the fire performance of real buildings is much better than expected. It is clear that there are large reserves of fire resistance in modern steel-framed buildings and that standard fire resistance tests on single unrestrained members do not provide a satisfactory indicator of the performance of such structures.

This publication is concerned with the design of modern multi-storey steel-framed buildings using composite construction, i.e. the floors are constructed using shallow composite slabs with profiled steel decking attached by shear connectors to downstand beams. It has been prepared following research into the behaviour of complete buildings in fire, including studies of actual buildings following real fires, full-scale fire tests at Building Research Establishment, Cardington and at BHP, Melbourne, Australia, as well as small-scale fire tests and computer modelling of structural behaviour.

The publication is in three parts:  
Part A contains design recommendations based on the observed behaviour of the Cardington test structure, supplemented by mathematical modelling.
Part B contains the background to the recommendations and includes a review of the experimental work in the UK and other countries and a discussion of how elements of construction behave in fire.
Part C contains appendices and references.

In this ‘Level 1’ guide, recommendations are presented for low risk buildings, i.e. those in which the elements of structure are normally only 15, 30 or 60 minutes fire resistance. The recommendations apply to braced composite frames using composite slabs and shallow decking.

The tests and observations examine the behaviour of both protected and unprotected steel structures in detail.  Attention is given to columns, beams, edge beams, and lintels as well as the connections provided by bolts, welds, end plates, fin-plates and cleated-plates.  The behavioural and deformation characteristics of floor slabs including composite steel decking is assessed.  Evidence of buckling, tensile and flexural behaviour, and the response of columns and beams to shear stress, squashing, rotational and axial stress is considered. The observations conclude with sections on the overall building stability and bracing, the effects of compartmentation and a review of other influences.

Primary author(s): G M Newman BSc(Eng) MIStructE MIFireE, J T Robinson BSc CEng MIM MCIM, C G Bailey BEng PhD

Source: Corus
Published by the Steel Construction Institute, 2000

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