UPGRADING CONTINUOUS REINFORCED-CONCRETE BEAMS BY GLUING STEEL PLATESTO THEIR TENSION FACES

It is now fairly common practice to glue steel plates to the tension f aces of existing reinforced concrete slabs, as it is an inexpensive an d unobtrusive upgrading procedure for strengthening and stiffening. Ho wever, the application of this technique to continuous reinforced-conc rete beams, as opposed to slabs, is severely restricted by premature d ebonding of the ends of the tension-face plates through the action of vertical shear forces, that is, shear peeling. An experimental study i s presented in which steel plates are glued to the sides of reinforced -concrete beams specifically to inhibit shear peeling of the tension-f ace plates. The results are incorporated into a design procedure for p lating the tension faces of continuous composite beams that can allow for any distribution of applied loads, any variation of the cross-sect ion properties along the length of the beam, and the time effects of c reep and shrinkage, as well as propped and unpropped construction. The procedure is then applied to the strengthening and stiffening of a co ntinuous reinforced-concrete beam for strength and serviceability requ irements.