Hollow Composite Reinforcing Systems for Precast Concrete Slabs

Abstract

AbstractA hollow fibre composite reinforcing system (CRS) has been designed and developed to create a void and a shear connector in reinforced concrete structures and, at the same time, provide an additional reinforcement to the structures including dry walls, slabs and bridge decks. This presentation will focus on the results of an experimental investigation on the flexural behaviour of precast concrete slabs with hollow CRS and glass fibre reinforced polymer bars. Four full-scale concrete slabs, i.e. solid slab, slab with a hollow-core, slab reinforced with GFRP bars and CRS and slab reinforced with steel bars and CRS were cast and tested up to failure under four-point static bending. The failure behaviour, load–deflection behaviour and failure load of these slab systems were evaluated and compared. The results showed that the CRS enhanced the structural performance of hollow core concrete slabs. The slab with three CRS increased the stiffness of the slab by 33%, reduced the loss of stiffness after concrete cracking by 24%, increased the load-carrying capacity by 45% and significantly increased the deformability by 117%. The hollow composite system also prevented vertical flexural cracks starting from bottom and propagating up to the top layer of concrete, this resulted in ductile flexural failure. From these results, it was clearly demonstrated the effectiveness of CRS in concrete slabs indicating that a thinner concrete slab with CRS is possible to achieve the same strength and stiffness of solid and hollow slab resulting in a more lightweight and economical structure.