Revisiting the Code Design Equations for Concrete Columns Reinforced with GFRP Bars

Over the previous three decades, researchers have dedicated significant efforts towards the advancing of glass fiber-reinforced polymer (GFRP) bars, aiming to address the challenges arising from corrosion in traditional steel reinforcement bars. This study intended to find the most efficient relation to compute compression load capacity for concrete columns of circular sections reinforced with GFRP through surveying equations from previous research and comparing the relations of the most popular GFRP codes (JSCE, AS, CSA, and ACI). The statistical analysis of the equations depends on a comparison of practical and theoretical load capacities, Young's modulus, compressive concrete strength, ratios of longitudinal and both types of transverse reinforcement, spirals, and hoops. The results of CSA and AS were close to each other, and they were better than those of JSCE and ACI regarding being efficient, safe, and consistent. In addition, JSCE demonstrated a high level of conservative in all the studied parameters, followed by the ACI, while the CSA and AS showed very low conservative rates. Furthermore, the AS showed superiority in all the studied parameters. In terms of statistical metrics, the AS exhibited a very low error rate. It was concluded that the AS relation is the most efficient and superior relation for computing the axial load carrying capacity (ALCC) of all the studied parameters, followed closely by the CSA code equation, and with a slightly larger margin, the ACI code equation then JSCE code equation with a slightly very large margin.