Detection on debondings in FRP-strengthened reinforced concrete beams

Resumen

Advanced composite materials are increasingly used in the strengthening of reinforced concrete (RC) structures. This strengthening method is often associated with a brittle and sudden failure caused by some form of FRP bond failure which may be originated at the termination of the FRP material and propagate towards the midspan or in the vicinity of flexural cracks in the RC beam and propagate towards the FRP termination. Hence, flexural cracking of the RC beam has a major influence on the overall response of the strengthened member, and it affects the distribution of the stresses in the various constituents of the strengthened member. In addition, this failure mode will affect the dynamic response of the beam by altering its natural frequencies. As a result, considerable analytical, numerical and experimental efforts should be made to capture these phenomena. An optimization method based on spectral elements is proposed here for detection of local debondings in RC beams externally strengthened with FRP