Investigation on the behaviour of concrete composite slab system with different levels of interface shear design

Concrete composite slab system, comprised of two half-slabs connected integrally through shear connectors, has gained popularity due to fast-track construction of bridges and buildings. Flexural performance and level of composite action of composite slab system depend on its interface shear connection. In the present study, the behaviour of composite slab system with different levels of interface shear design is assessed through experimental and numerical investigations. From the investigations carried out on concrete composite slabs, it is clearly identified that the interface cohesion is an important parameter which contributes to the stiffness of the system. It is also observed that the concrete composite slabs showed load-displacement response similar to that of control full slab, irrespective of the number shear connectors provided, when the cohesion mobilised is sufficient to cater to the shear demand. It is also observed that in the absence of contribution from interface cohesion, full composite action cannot be achieved even when full shear connection design is provided based on shear friction alone. Furthermore, in the absence of the interface shear reinforcement, the displacement sustained by the composite slab is much lower and failed at lower ultimate displacement compared to that of the control full slab.