Effect of tapered FRP sheets on interlaminar fracture behaviour of FRP–concrete interface

External bonding of fibre reinforced plastic (FRP) sheets to reinforced concrete beams has been accepted as an effective strengthening method. The use of taper ended FRP sheets can further enhance the strengthening performance, improving both the load carrying capacity and the corresponding deflection beyond those of the beams bonded with FRP sheets of a constant thickness. This paper presents experimental and analytical investigations regarding the influence of tapered FRP sheets on interlaminar fracture resistance between the FRP and concrete. The asymmetric double cantilever beam test was used to measure the interlaminar fracture resistance. The results showed that the taper configuration could significantly affect the interlaminar fracture behaviour in terms of both the load–displacement behaviour and the variation of critical strain energy release rate with crack propagation.