Experimental and numerical study of end anchorage in composite slabs

Composite steel-concrete slabs are widely used in floor construction in steel-framed buildings where the connection between the steel beam and the concrete slab through shear connectors exploits the best combination of each component. The end anchorages in combination with other shear transfer mechanisms play an important role into the strength, stiffness and ductility of composite slabs. In this paper, a series of tests were carried out on both solid and profiled composite slabs to investigate the effect of end anchorage on the ultimate load carrying capacities and failure modes. The test programme consisted of eight composite slab specimens under restrained and unrestrained conditions. The load-deflection relationships and failure modes of all slabs are presented. The test results showed that end anchorage has a positive effect on the ultimate strength of both solid and composite slabs irrespective of the long term loading conditions. A three-dimensional finite element model is developed to simulate the behaviour of composite slabs with end anchorages. The model was validated against experimental results for its accuracy and a parametric study was conducted to investigate the influence of concrete strength, shear stud strength and profiled steel sheeting thickness in profiled composite slabs. The results showed that the effect of concrete strength and sheeting thickness on the load-deflection behaviour is significant. However, the shear bond stress-slip rather than the strength of the shear studs governs the contribution of the end anchorage to the shear bond capacity of composite slabs.