Experimental and analytical study of shear behavior in reinforced concrete beams usi̇ng glass fi̇ber reinforced polymer composite sheets

When reinforced concrete structures are exposed to natural disasters such as earthquakes, hurricanes and sudden loads such as explosions, they can suffer great damage. When the damaged structures as a result of these effects are examined, it is seen that the migration in the building elements is mostly caused by shear damage. Shear failure is caused by various reasons. From these reasons; insufficiency of shear reinforcement, decrease in reinforcement area due to corrosion, increase in service loads etc. can be listed as Within the scope of this thesis study, the shear behavior of reinforced concrete beams strengthened with Glass Fiber strengthened Polymer (GFRP) strips was investigated experimentally and analytically. For this purpose, 9 reinforced concrete T-beam specimens equipped with longitudinal reinforcing bars were fabricated to determine shear failure. Geometry and reinforcement properties were chosen the same in all test specimens. One of the beam samples was produced as a reference. The other 6 beams are wrapped with a single layer of GFRP in different wrapping styles. In the remaining two reinforcements in the partial GFRP application, the glass fiber was fixed to the beam with anchors at different angles (45o and 90o). The load and displacement values of all specimens were recorded until they broke under an increasing load in 10 kN periods. The experimental results obtained were compared with the empirical regulations provided by ACI 440.2R-17, TBEC-2019 and FIB-2001. Experiments have shown that the reinforcement method with glass fiber strengthened polymer composites has a role in reducing shear deformation in reinforced concrete beams. In addition, the applied strengthening method caused the breaking mode to change in some winding models. While shear damage occurred in strengthened TB-1, TB-2 and TB-3 samples, TB-4, TB-5, TB-6, TB-7 and TB-8 samples showed ductile behavior and broke due to bending. As a result of the study, by comparing the experimental and analytical results, it was seen that the empirical relations gave very conservative values compared to the experimental results. Keywords: Reinforced Concrete Beams, Glass Fiber strengthened Polimer (GFRP), Fiber strengthened Polymer (FRP), Shear Behavior, Reinforcement.