Behaviour of composite beam-slab floor systems under fire conditions

Due to some fire incidents widely known as the Basingstoke and the Broadgate Fires, composite slabs consisting of steel beams and lightly reinforced concrete slabs with steel decking showed an inherent load-carrying capacity which had not been taken into account by any building code. Previous research works later have shown that fire resistance of composite slabs can be considerably enhanced if tensile membrane action can be mobilised at large displacements. However, there are some gaps in the understanding of membrane behaviour of composite floor systems in fire. The objectives of the research work are to: (1) Quantify the physical behaviour of concrete slabs incorporating realistic behaviour of fire-protected composite edge beams by conducting two test series on composite beam-slab floor systems (CB-S systems) under fire conditions; (2) Develop the finite element models which can predict the fire behaviour of CB-S systems; (3) Propose a semi-analytical approach to estimate the load-bearing capacity of CB-S systems in fire; (4) Propose design recommendations on the current design approach using the concept of tensile membrane action.Doctor of Philosophy (CEE