Design guidelines for flexural strengthening of RC beams with FRP plates

Bonding composite plates to reinforced concrete beams is an effective technique of repair and retrofit. The ultimate capacity of the strengthened beam is controlled by either compression crushing of concrete, rupture of the plate, local failure of concrete at the plate end due to stress concentration, or debonding of the plate. These failure modes have been considered for developing design guidelines for strengthening reinforced concrete beams using fiber composite plates. The effect of multistep loading of the beam, before and after upgrading, has been included in these guidelines. Limit state design concept has been followed in this paper. Terms, definitions, and notations compatible to design guidelines for ordinary reinforced concrete beams have been used.