Strengthening Reinforced Concrete Beams with CFRP and GFRP

Abstract

Concrete beams were strengthened by wrapping the shear edges of the beams twice at 45° in opposite directions by either carbon fiber reinforced polymer (CFRP) or glass fiber reinforced polymer (GFRP). The study included 3 CFRP wrapped beams, 3 GFRP wrapped beams, and 3 control beams, all of which were 150×250×2200 mm and manufactured with C20 concrete and S420a structural steel at the Gazi University Technical Education Faculty labs, Turkey. Samples in molds were cured by watering in the open air for 21 days. Four-point bending tests were made on the beam test specimens and the data were collected. Data were evaluated in terms of load displacement, bearing strength, ductility, and energy consumption. In the CFRP and GFRP reinforced beams, compared to controls, 38% and 42%, respectively, strength increase was observed. In all beams, failure-flexural stress occurred in the center as expected. Most cracking was observed in the flexural region 4. A comparison of CFRP and GFRP materials reveals that GFRP enforced parts absorb more energy. Both materials yielded successful results. Thicker epoxy application in both CFRP and GFRP beams was considered to be effective in preventing break-ups.

Behavior of reinforced concrete beam with CFRP and GFRP laminates

“…This is the typical failure mode for un-strengthened RCC beams under flexure. The failure load for the un-strengthened beam was the lowest related to the other strengthened beams, indicating that the beam was unable to withstand given load [16]. The CFRP-strengthened beams failure occurred due to the failure of the CFRP laminate or splitting of concrete at the tension face.…”

A State-of-the-Art Review on Structural Strengthening Techniques with FRPs: Effectiveness, Shortcomings, and Future Research Directions

“…GFRP is employed in the construction of bridges and structural members such as beams and columns, domes, and other non-structural elements. GFRP is cheaper than other FRP composites used in the construction industry [12,59,60]. GFRP consists of glass fibers to improve the strength and stiffness of plastics [51,52].…”

Flexural performance of RC beams externally strengthened with a single-layer of basalt fiber reinforced polymer sheets

“…Also, several researchers carried out experimental investigations on RC beams/girders strengthened with carbon, glass and aramid fiber reinforced polymers composites in order to study their performance. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] Basalt fiber is a modern alternative reinforcement in the industry. Basalt fibers contain natural materials without any additives, also slightly stronger and stiffer than glass, nontoxic, noncorrosive, nonmagnetic, and environmentally safe; and their tensile strength and elastic modulus are 30% higher than E-glass and S-glass fibers.…”