When considering contemporary threats in our society, the question how safe our structures are in case of events that are normally unaccounted for in the design is very relevant. The current research proposal provides novel insights in order to quantify the behaviour of frequently used prefabricated concrete floor systems when such unforeseen events or a fire situation would occur. By developing accurate models, the design against such events can be improved in order to provide an enhanced safety in case such events occur. This increases the probability of safe evacuation. Both detailed numerical models as simplified analytical engineering models will be developed, focussing on the behaviour of real floor systems subjected to large deformations. The models will be validated by an experimental test program on hollow-core slabs and floors. Appropriate target levels of the additional strength reserve for these elements will be derived taking into account different levels of hazards as well as the occupancy of the structure and taking into account economic aspects. Finally, also design recommendations as well as a decision tool for making proper design adjustments will be developed.