Strengthening efficiency of taper ended FRP strips bonded to RC beams

External bonding of fiber reinforced plastic (FRP) strips to reinforced concrete (RC) beams has been widely accepted as an effective method for strengthening and rehabilitation of aging civil structures. The FRP strips improve significantly the ultimate flexural strength of RC beams. This paper reports the effectiveness of taper end FRP design in further enhancing the structural performance of strengthened RC beams. The relative performance of taper distance was specifically evaluated in an effort to optimize the FRP strip end geometry for given RC beam dimensions. With rehabilitation of damaged and/or aging structures in mind, precracked RC beams were also studied. The four point bending experiment indicated that the tapered FRP strip end design augmented significantly the ultimate load and mitigated the reduction in beam deflection corresponding to the ultimate load, compared to the beams bonded with constant thickness FRP strips. There was negligible difference in flexural performance between the virgin and precracked RC beams after they were bonded with taper ended FRP strips, indicating that the tapered FRP design concept can be applied to both undamaged and aging/damaged structures.