This review of current design rules for fire resistance of reinforced concrete structures examines many of the assumptions on which these rules are based and presents evidence suggesting that the rules may be inadequate both for the assessment of the effects of spalling and the prevention of collapse. Initially it reviews the consequences of spalling on the performance of key concrete elements within a structure before describing effects which occur in complete structures that are not apparent from standard fire tests. This includes a review of fire incidents in real buildings, a compartment fire test carried out on the concrete frame at BRE Cardington, and a comparison with numerical models of concrete in fire. Results are also presented from a recent furnace test on a restrained post-tensioned slab. It concludes with a call for a fundamental review of the basis of the current rules and programme of testing of modern structural components.
Fergal Kelly, BEng, PhD, CEng, MIStructE, Peter Brett Associates, London
John Purkiss, BSc(Eng), PhD, CEng, MIStructE, MICE formerly Aston University