FLEXURAL BEHAVIOR OF SHEAR-CRACKED REINFORCED CONCRETE BEAM STRENGTHENED WITH GFRP SHEET

The most dangerous shear failure behavior is brittle collapse that occurs without warning of deflection. So that the structural reinforcement of shear strength will be one solution to make the structure meet safety requirements. GFRP as a material that has high tensile strength, good ductality, light weight, so easy to mobilize. The purpose of this study: to analyze the capacity of the melting moment and the ultimate moment of concrete beams by strengthening the GFRP sheet and the efficient use of the GFRP sheet. This research was conducted with an experimental method (static load) on the shear strength of reinforced concrete beam structures using GFRP external shear strength. Type of GFRP shear reinforcement : U-wraping (BGP-1), Ustrips vertical width 75mm(BGP-2), U- strips vertical width 100mm (BGP-3), Uinclined strip 450 width 75mm (BGP-4), U-inclined strip 450 width 100 mm (BGP5).The results showed that: Percentage of experimental yield moments of BGP-1, BGP-2, BGP-3, BGP-4 and BGP-5 beams for beams without BN reinforcement respectively: 12.9%, 3.0%, 5.1%, 11.5% and 12.5 %.Percentage of experimental ultimate moments of beams BGP-1, BGP-2, BGP-3, BGP-4 and BGP-5 to beams without BN reinforcement successively: 11.7%, 5.8%, 7.4%, 7.7% and 8.9%. The beam has a shear crack, so the continuous U reinforcement along the shear region produces the highest yield moment and ultimate capacity. Strengthening U- strips vertical width 100mm (BGP-3) is more efficient (GFRP sheet area of 0.225m2 ) and the method of implementation is simpler when compared to BGP-2, BGP-4 and BGP-5 beams. Based on the maximum moment capacity (ultimate), then the beam with the Uwraping (BGP-1), that is most suitable for use only requires a less efficient GFRP area (GFRP area 0.425m2 ).