Shear Behavior of Seawater–Sea Sand Concrete Beams Reinforced with BFRP Bars and Stirrups

Abstract

The shear behavior of basalt fiber–reinforced polymer-reinforced seawater–sea sand concrete (BFRP-SSC) beams was investigated experimentally. The effects of several factors, including stirrup diameters (8, 10, and 12 mm), stirrup spacings (100, 125, and 150 mm), and shear span-to-depth ratios (1.55, 1.95, and 2.35), were considered. The results demonstrated that the shear mechanism of the diagonal section of BFRP-SSC beams could be explained using the arch truss model. Moreover, the shear span-to-depth ratio significantly influences the shear capacity, bending stiffness, diagonal crack width, and shear failure mode of beams, with diagonal compression failure occurring in beams with a ratio of 1.55 and shear compression failure occurring in beams with a ratio between 1.95 and 2.35. In addition, the actual shear capacities of 72 BFRP-reinforced concrete (BFRP-RC) beams were compared to the results obtained by five design provisions. Correction coefficient of shear span-to-depth ratio, modification to stirrup spacing, correction equation of stirrup strain, and shear contribution coefficient of stirrups were proposed to modify the shear equation in ACI 440.1R-15. The results of the modified shear equation showed a good agreement with the actual shear capacities of beams. The findings of this research have theoretical significance for the design and practical application of BFRP-SSC beams in marine construction.