Existing concrete beams may need local strengthening to improve its serviceability for many occasions namely due to crack in concrete, corrosion, up-gradation of highways and improving load carrying capacity of the beams. In such cases the external reinforcement of structural member using steel plate may be advantageous over new constructions. The commonly adopted techniques for strengthening and stiffening of RC structure are namely, epoxy bonding of steel plates, epoxy bonding of FRP (Fiber Reinforced Plastic) plates, by providing additional reinforcement, by providing external pre stressing, bolting of steel plates/FRP plates. In the present study a simple cost-effective method were adopted by bolting steel/FRP plate to the element in the tension zone or shear zone as an additional reinforcement to have maximum effect on ultimate strength, stiffness, deflection and crack control. Basic principle of reinforced concrete design was applied in the design procedure. The method of reinforcement involve the attachments of steel and GFRP plates to Bottom face (tension face) as well as side face of the beam of the existing reinforced concrete members using anchor bolts. The anchor bolts at various spacing along the under side of the member, were the only attachment used in the present retrofit procedures. The construction procedure required little member or plate preparation prior to installation. The anchors used were expansion type. The use of anchors for the entire length of the external reinforcement automatically inhibits tear off behavior near the plate termination prior to design load levels. Precaution was taken to avoid contact with existing flexure reinforcement while drilling.
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