Strength and Behavior of Confined Steel Fiber Reinforced Concrete Columns

An experimental investigation was performed on the strength and behavior of short, confined reinforced concrete columns with and without steel fibers. The columns were subjected to monotonic axial compression until failure. The volume fraction (1.5 percent) and aspect ratio (70 of steel fibers used) were the same in all the confined steel-fiber reinforced concrete (SFRC) columns. The primary variable considered was the amount of lateral steel. Four different percentages of volumetric ratio of lateral reinforcement, 0.6, 0.8, 1.6, and 2.4 percent, were used. The stress-strain characteristics and equivalent confinement conditions of confined SFRC and confined reinforced concrete columns were compared. As the earlier models proposed for confined reinforced concrete did not compare satisfactorily with the experimental values of confined SFRC specimens, an analytical model for confined SFRC was proposed. Improved strength and strain at peak loads of confined reinforced concrete columns was examined.