Axial Load Performance of GFRP-Reinforced Hollow Concrete Columns

The limited understanding on the nature of the internal stress formation in hollow concrete columns (HCCs) reinforced with steel bars often led to brittle failure behavior either by buckling of the longitudinal bars or concrete wall crushing. Moreover, the corrosion of steel bars in HCCs is a crucial issue due to their exposed inner and outer surfaces. This study systematically investigated the effect of major design parameters controlling the structural behaviour of HCC reinforced with Glass Fibre Reinforced Polymer (GFRP) bars under concentric compression loading. It focuses on investigating the effect of inner-to-outer diameter ratio (i/o), reinforcement ratio (ρ), volumetric ratio (ρv), and concrete compressive strength (\({\text{f}}_{{\rm{c}}}^{\prime }\)). It also aims at demonstrating the effective use of GFRP bars as internal reinforcements for the reliable, safe and durable HCCs. Finally, this study critically discusses the stress mechanism difference between the hollow and solid concrete columns and identifies new simplified definition for the ultimate compressive strength capacity of the HCCs.