Strengthening of RC beams by FRP laminates: effects of various parameters on peeling-off
Résumé
The flexural strength of a reinforced concrete beam can be increased by bonding a FRP sheet to its tension face and this method is an alternative to deconstruction and reconstruction. Nevertheless, this type of reinforcement may cause a premature debonding failure. This paper is concerned with the failure by concrete cover separation; in other words by peeling-off which involves the tearing-off of the concrete cover along the level of tension steel reinforcement starting from a plate end. This type of failure prevents the strengthened RC beams from attaining their ultimate flexural capacity; furthermore, it is brittle and unique to beams bonded with a soffit plate. In this study, a reliable numerical model dedicated to the prediction of this failure mode is introduced. It should be noted that the proposed finite element model has been validated by comparing numerical results with experimental ones. The key parameters affecting the efficiency of the strengthening by bonding are then identified as part of a parametric study. The results of this study are compared with test results in the literature demonstrating the effectiveness of the proposed model. Finally, several measures are proposed to improve the performance of the strengthening and avoid the peeling-off failure.