Strengthening of reinforced concrete beams by epoxy glued steel plates

STRENGTHENING OF REINFORCED CONCRETE BEAMS BY EPOXY GLUED STEEL PLATES (M.Sc. Thesis) Mehmet ARSLAN GAZI UNIVERSITY INSTITUTE OF SCIENCE July, 1991 ABSTRACT The use of epoxy glued steel plates is one of the most practical techniques among various methods of strengthening commonly used for reinforced concrete structural members. In the present investigation, a total of nine medium size (15 cm x 25 cm cross-section) reinforced concrete beam specimens were tested under monotonical ly applied load. Six of these specimens were strengthened by using epoxy glued steel plates of various properties; two were repaired (following considerable damage) by the same method and the ninth was the basic beam used as the reference specimen. In the study, (a) efficiency of the method, (b) effects on the behaviour and strength of the length and (c) thickness of the strengthening steel plate, (d) condition of the plate ends (free, welded or held in place by steel collars), (e) type of intervention (unloaded intervention or intervention under load) were investigated. The central test zone of the specimens were subjected to pure bending and deflections, rotations (and thus curvatures) were measured. On the basis of the experimental and theoretical load-deflection and moment-curvature relationships, the performances of the specimens were evaluated as regards strength, ductility, energy dissipation, strength degradation, stiffness etc. It was observed that - a satisfactory strength level can be achieved when plate is sufficiently long and its ends are properly held in position either by welding or by end collars. However, the method did not appear to be as satisfactory as the conventional method of strengthening (where a new reinforced concrete layer is introduced) from ductility and energy dissipation points of view. It was also observed that proper workmanship is also very essential. Key words t Beam repair, Beam strengthening, Epoxy repair, Plate glueing, Beam behaviour Supervisor: Dr. Hüsamettin EVİRGEN 75 Pages IV