This paper examines the applicability of the plate bonding technique to strengthen structurally damaged rein forced concrete beams. Two types of strengthened beam were tested. In the first, beams loaded up to 70 % of their flexural capacity were unloaded and strengthened in the unloaded state. In thesecond, beams also loaded up to 70 % of their flexural strength were reinforced with bonded plates while under load. The structural behaviour of these two types of strengthened beam is reported in terms of deflection, concrete and steel strain, cracking behaviour, flexural stiffness and strength. It is shown that strengthening, by bonding steel plates, of significantly cracked beams is structurally efficient and that the plated beams are restored to stiffness and strength values superior to those of the original unplated beams. The data show that complete confidence and reliability can be placed in applying the technique to structurally damaged members. The repaired composite beams are able to preserve their structural integrity and maintain composite action until failure. Further, the composite structural system obeys simple laws of mechanics right up to failure.
R.N. Swamy, R. Jones and A. Charif