Membranwirkung von Verbunddecken bei Brand - Numerische Untersuchungen

In case of fire composite beam slab systems show a very good behaviour. Due to large deformations membrane forces are activated inside the slab and thus, load bearing capacity reserves can be used. German building regulations divide the supporting structure in fictive structural members. Each member must fulfil the requirements even though it is not necessary for the load transfer in the system. Secondary beams are not necessary at elevated temperatures and can be left unprotected. In Great Britain and Switzerland membrane action is already used to design slab systems in fire ([1] to [5]). To enable such design rules in Germany further investigations are required. For this reason a research project was initiated by the authors. The project is supported by the DASt and AiF. In [6] the state of research and the idea of membrane action are already described. The experimental set-up and results are shown in [7]. In this paper the numerical investigations of the project are presented.