Ultimate capacity prediction of carbon fiber reinforced polymers (CFRP) strengthened reinforced concrete flexural elements based on debonding failure

Abstract

The ultimate strength of reinforced concrete elements retrofitted in flexure by means of externally bonded carbon fiber reinforced polymers (CFRP) has attracted the attention of researchers due to many advantages highlighted by a wide set of experimental results. The current paper presents analytical and experimental study on reinforced concrete (RC) flexural elements strengthened for flexure with externally bonded CFRP. A simple yet rational model is developed, based on cross sectional analysis, satisfying strain compatibility and equilibrium conditions, whichis capable of predicting the ultimate moment capacity of (Fiber Reinforce Polymers) FRP strengthened flexural sections. A total number of nine specimens, includingthree beams, and six numbers ofone way spanning slabs were cast. One beam and three slabs were kept as control specimens having no strengthening with CFRPand the other specimens were strengthened with CFRP laminates and tested under the “four point loading arrangement”.Debonding strain at the ultimate failure is calculated based on the experimental results and compared with the existing design standards. The test results indicated that significant enhancement of load carrying capacity can be achieved by externallyreinforced with CFRP.