Behavior of High-Strength Concrete Columns under Cyclic Flexure and Constant Axial Load

This paper presents the results of a study conducted on six large-scale columns made of high-strength concrete (HSC). The columns were subjected to constant axial loads corresponding to target values of 15, 25, and 40% of the column axial-load capacity and a cyclic horizontal load-inducing reversed bending moment. It is shown that tie spacing, and therefore tie volumetric ratio and axial-load level, have significant effects on the flexural behavior of HSC columns. The need to include the axial-load level in code requirements for confinement reinforcement is pointed out.