Retroffitting by adhesive bonding steel plates to the sides of RC beams. Part 1: Debonding of plates due to flexure

A convenient method for enhancing the strength and stiffness of existing re inforced concrete beams is to bond adhesively steel plates to their tension faces. However, there is a limit to the applicability of tension face plat ing as the tension face plates are prone to premature debonding and, furthe rmore, the addition of the plate reduces the ductility of the beam. An alte rnative approach to tension face plating is to bond adhesively steel plates to the sides of reinforced concrete beams, as side plates are less prone t o debonding and can allow the beam to remain ductile. Debonding at the ends of the side plates due to flexural forces, that is flexural peeling, is st udied in this paper. A fundamental mathematical model for flexural peeling is developed, which is calibrated experimentally to produce design rules fo r preventing premature debonding of the plate-ends due to flexural forces. In the companion paper, the effect of shear forces on flexural peeling is q uantified to produce design rules that are applied to the strengthening and stiffening of continuous reinforced concrete beams.