Stability of RC Structure Under Non-Uniform Thermal Exposure

This paper investigates the effect of a uniform temperature design fire assumption upon structural response. The structural behaviour when exposed to the non-uniform gas temperatures above a fire plume (the Alpert correlation [I]) is compared with the structural behaviour when exposed to uniform gas temperature, using either the average or maximum of the non-uniform gas temperatures. A two-way spanning reinforced concrete slab is used as the test case. It is found that the non-uniform gas temperature distribution causes localised failures underestimated by the average gas temperature assumption. The maximum gas temperature assumption provides a conservative estimate of behaviour. The varied response elicited by differing assumptions concerning the thermal exposure highlights the need for an improved design philosophy for structures in fire.