Upgrading Continuous Reinforced Concrete Beams by Gluing Steel Plates to their Tension Faces

Abstract

It is now fairly common practice to glue steel plates to the tension faces of existing reinforced concrete slabs, as it is an inexpensive and unobtrusive upgrading procedure for strengthening and stiffening. However, the application of this technique to continuous reinforced-concrete beams, as opposed to slabs, is severely restricted by premature debonding of the ends of the tension-face plates through the action of vertical shear forces, that is, shear peeling. An experimental study is presented in which steel plates are glued to the sides of reinforced-concrete beams specifically to inhibit shear peeling of the tension-face plates. The results are incorporated into a design procedure for plating the tension faces of continuous composite beams that can allow for any distribution of applied loads, any variation of the cross-section properties along the length of the beam, and the time effects of creep and shrinkage, as well as propped and unpropped construction. The procedure is then applied to the strengthening and stiffening of a continuous reinforced-concrete beam for strength and serviceability requirements.