FIRE RESISTANCE OF COMPOSITE SLABS

Composite slabs are slabs in which profiled steel sheeting acts as a p ermanent formwork and as reinforcement to the concrete placed on top. During fire the sheeting heats up and loses strength. However, tests h ave shown that due to the heat absorbed by the concrete, the performan ce is better than that of unprotected steel and that fire resistance o f composite slabs is at least 30 minutes. For fire ratings of 60 minut es or beyond, additional measures usually have to be taken, of which t he application of additional reinforcement is usually the most economi cal. Recommendations were established by the ECCS in 1983, enabling a quick and simple calculation of the fire resistance of composite slabs to be made. These recommendations were taken as a basis for Eurocode 4-Part 1.2. 'Structural Fire Design'. This paper describes the calcula tion method of EC 4 and considers some new research developments that could be implemented in newer versions of the Eurocode, leading to a m ore economic design of composite slabs.