In this study, the behavior of reinforced concrete slabs bonded with fiber-reinforced polymer (FRP) reinforcement was investigated. Twelve square slabs, with a tension steel ratio of 1.28% in each direction, were prepared using a concrete mix with a target cylinder compressive strength of 30 MPa. Except for the reference slab, they were strengthened with three different FRP systems, namely discrete carbon FRP plates, continuous carbon fiber sheets and continuous glass fiber fabric. Each slab was simply supported along its edges and subjected to a concentrated load over a square area at its center. The load-deflection response of the strengthened slab was characterized by four regimes: un-cracked regime, cracked regime, post-yield regime, and post-peak regime. The FRP reinforcement registered strains of about 20% of the ultimate strain capacity and de-laminated from the slab at failure. Slabs bonded uni-directionally with FRP system did not exhibit significant increase in punching shear resistance. However, for slabs bonded bi-directionally, the punching shear strength increased with the reinforcing index. Also, for the same reinforcing index, carbon fiber sheets gave the highest punching shear strength while those with carbon FRP plates gave the least. A strength enhancement factor was proposed to evaluate the punching shear resistance of the strengthened slab.
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