SHEAR REPAIR FOR REINFORCED-CONCRETE BY FIBERGLASS PLATE BONDING

Reinforced concrete structures often exhibit structural and nonstructu ral cracking due to a variety of reasons. Major cracks are signs of di stress and require immediate attention. Results from a study on streng thening of reinforced concrete beams having deficient shear strength a nd showing major diagonal tension cracks are presented in this paper. The beams with deficient shear strength were damaged to a predetermine d level (the appearance of the first shear crack) and then repaired by fiberglass plate bonding (FGPB) techniques. Different shear repair sc hemes using FGPB to upgrade beams' shear capacity were use& FGPB repai r by shear strips, by shear wings, and by U-jackets in the shear span of the beams. Experimental data on strength, stiffness, steel strain, deflection, and mode of failure of the repaired beams were obtained, a nd comparisons between the different shear repair schemes and the unre paired control beams were made. Shear repair by FGPB is shown to incre ase shear capacity and restore the degraded stiffness of the beams. Th e study results also show that the increase in shear capacity by FGPB was almost identical for both strip and wing shear repairs. However, t his increase was not adequate to cause beams repaired by these two sch emes to fail in flexure. On the other hand, the enhanced shear capacit y by U-jacket was sufficient that flexural failure occurred for these beams.