Experimental investigation of a novel FRP-concrete composite floor slab

This paper presents the findings of an experimental investigation of a novel FRP-concrete composite floor system. The system consists of a moulded glass fibre reinforced polymer (GFRP) grating adhesively bonded to square pultruded GFRP box sections as structural formwork for a concrete slab. Holes cut into the top flange of the box sections at a variable spacing allow concrete ‘studs’ to form at the grating/box section interface. During casting, GFRP dowels are inserted into the holes to further connect the grating and box sections. Following component tests on the concrete-filled grating and shear connectors, six (300 x 150) mm and 3000 mm long slab specimens were designed and tested under five-point bending. From the resulting load-deflection curves, it was determined that all specimens behaved elastically and fully compositely until the initial peak was reached. No slip was observed between the concrete and GFRP box sections until the longitudinal shear failure occurred at the initial peak. The load capacity carried on increasing at a reduced stiffness in a progressive manner, with significant residual strength and slip observed. All specimens failed by the separation of the webs and flange at the upper corners of the box sections due to the large curvature induced. Full-scale experimental results demonstrated that the controlled longitudinal shear failure provided deformability to the overall system and a robust interaction between the concrete and FRP formwork was achieved.