4. The analytical models using the Hognestad’s parabola provided an accurate estimate in the case of CFRP rupture and small loss in tension flange area. For the mode of failure due
to compression crushing of concrete and moderate loss of
tension flange area, the theory was fairly conservative. For
significant loss of tension flange and in order to consider the
debonding mode of failure, the stress concentration and peel-
ing stresses at the crack should be considered as the primary
cause of failure.