A generic structural engineering approach to retrofitting RC beams in buildings by adhesive bonding longitudinal plates

Retrofitting reinforced concrete structures by adhesive bonding steel or FRP plates to their surfaces is an efficient and inexpensive form of rehabilitation that is rapidly gaining in importance. The main problem with adhesive bonding plates to reinforced concrete is the very weak tensile strength of the concrete that allows premature debonding of the plate that can occur even before the serviceability loads are reached. There has been published much research on premature debonding, particularly for tension face plates, from which have been developed: design rules of thumb; analyses based on stress concentrations; and those based on fracture mechanics. Much of this research may appear to be confusing for structural engineers as they are often not based on a structural engineer's understanding of the familiar behaviour of reinforced concrete. In this paper, a new, simple and generic structural engineering approach is described for designing plated structures that are based on the fundamental principles and mechanisms of behaviour familiar to structural engineers who design reinforced concrete structures. It will be shown that this new approach can be applied to longitudinal plates: of any material type such as FRP or steel; of any size; of any cross-section such as flat plates, angle sections and U-sections; and that are adhesively bonded to any position such as the tension face, compression face and sides of the RC beams or slabs.