High-Strength Concrete Columns with Square Sections under Concentric Compression

Experimental research was conducted to investigate the behavior of square high-strength concrete columns confined by rectilinear reinforcement. Large-scale columns with concrete strengths between 60 MPa and 124 MPa were tested under monotonically increasing concentric compression. The test parameters included the volumetric ratio and spacing of transverse reinforcement, distribution of longitudinal reinforcement and resulting tie arrangement, yield strength of transverse reinforcement, and concrete compressive strength. The results indicate that high-strength concrete columns can be confined to achieve inelastic deformabilities usually expected of normal-strength concrete columns. This is done by providing increased volumetric ratio and/or higher grade of confinement reinforcement. The results of the experimental program are presented in the paper, along with recommendations for design.