Mechanical behaviour of concrete beams reinforced with CFRP U-channels

This paper presents selected findings from an experimental investigation that aimed to exploit the use of multidirectional carbon fibre reinforced polymer (CFRP) fabric as combined shear and flexural reinforcement in concrete beams. The results of the bond behaviour of rectangular prismatic concrete beams reinforced with three different CFRP fabric reinforcement configurations, a plain U-shaped channel, a U-shaped channel with aggregate coating, and a lipped U-channel section with intermittent closed loops, are presented. By considering the load response and the failure behaviour of the beams, it is shown that the use of an aggregate coating on internal and external surfaces of the CFRP channel ensured a better composite action between the CFRP reinforcement and the concrete than that between the plain CFRP channel and the concrete. On the other hand, provision of an anchorage system at the top end of the sides of the CFRP channel ensured a greater post-breakage capacity and a ductility compared to the beam with the plain CFRP channel. It is then shows that the use of U-shaped CFRP channels with aggregate coating and an anchorage system consisting of a lipped channel section with intermittent closed loops provided improved strength and ductility in concrete beams. The research output has potential to develop reinforcement systems for structurally optimised non-prismatic concrete geometries and also as permanent formwork/reinforcement in thin concrete members.