Shear peeling of steel plates bonded to tension faces of RC beams

Abstract

The technique of adhesively bonding steel or fiber-reinforced plastic plates to the surfaces of reinforced concrete (RC) structural elements is being adopted worldwide to strengthen or repair reinforced concrete buildings and bridges. However, the prevention of premature debonding or peeling of externally bonded plates is a most critical aspect of design. One of the major modes of debonding in plated RC beams is shear peeling induced by the formation of critical diagonal cracks caused by the applied vertical shear forces. In this paper, mathematical models are developed for quantifying the shear peeling resistance of RC beams bonded with plates of different configurations. These models are based on the simplified theory of plasticity concepts for shear in reinforced concrete beams and also on procedures to compute the bond strength between an adhesively bonded plate and a concrete element. The models are validated against 32 test results from reinforced concrete beams adhesively bonded with either steel plates or steel angles attached to the tension faces, or tension face plated beams additionally bonded with side plates to improve their shear peeling resistance.