DESIGN EQUATIONS AND GUIDELINES FOR REINFORCED CONCRETE BEAMS STRENGTHENED WITH FRP PLATES

Epoxy-bonding composite plates to tension face of reinforced concrete beams is an effective technique for flexural strengthening. This paper presents guidelines and equations for strengthening of concrete beams for flexure, using epoxy bonded fiber composite plate. Possible modes of failure of the strengthened beam include: compression crushing of concrete, rupture of plate, local failure of concrete at the plate end due to shear and peeling stress concentrations, and debonding of plate around flexural cracks. The modes of failure have been considered in determination of the ultimate flexural capacity of the strengthened beam. The effect of multi-step loading of the beam on stress calculations has also been included. Limit state design concept has been followed in a manner similar to design of ordinary reinforced concrete beams for ease of application of the guidelines and equations by practicing engineers.