Title: Performance of LWSCC Beams Reinforced with GFRP Bars without Stirrups under Shear
Author(s): Shehab Mehany, Hamdy M. Mohamed, Brahim Benmokrane
Publication: Structural Journal
Appears on pages(s):
Keywords: beams; lightweight self-consolidating concrete (LWSCC); GFRP bars; lightweight aggregate (LWA); shear strength; shear failure and cracking; load deflection; strain; shear strength predictions; design codes
Integrating glass fiber-reinforced polymer (GFRP) bars into lightweight self-consolidating concrete (LWSCC) would effectively contribute to producing lighter and more durable reinforced concrete (RC) structures. Nonetheless, the shear behavior of GFRP RC structures cast with LWSCC has not yet been fully defined. This paper reports experimental results on the behavior and shear strength of LWSCC beams reinforced with GFRP bars. The beams measured 3,100 mm (122.05 in.) long, 200 mm (7.87 in.) wide, and 400 mm (15.75 in.) deep. The test program included six beams reinforced with GFRP bars and one control beam reinforced with conventional steel bars for comparison purposes. The test variables were the reinforcement type and ratio and concrete density. The experimental results indicate that using LWSCC allowed for decreasing the self-weight of the RC beams (density of 1,800 kg/m3) (112.4 lb/ft3) compared to normal-weight concrete (NWC). All beams failed as a result of diagonal tension cracking. Increasing the axial stiffness of the longitudinal GFRP reinforcing bars improved the concrete shear capacity of the LWSCC beams. The test results of this study and the results for 42 specimens in the literature were compared to the current FRP shear design equations in the design guidelines, codes, and literature. Applying a concrete density reduction factor of 0.8 and 0.75 in the ACI 440.1R-15 and CSA S806-12 shear design equations, respectively, to take into account the influence of concrete density achieved an appropriate degree of conservatism equal to that of the equations for NWC beams.