Circular high-strength concrete columns under simulated seismic loading

Behavior of high-strength concrete columns with concrete strengths of up to 90 MPa was investigated experimentally. Large-scale columns were tested under different levels of constant axial compression and incrementally increasing lateral deformation reversals. The columns had a circular cross section and circular transverse reinforcement. Different volumetric ratios and grades of steel were used to confine the core concrete. The results indicate that the deformability of high-strength concrete columns can be improved significantly through confinement. Inelastic drift capacity of columns can be improved to levels well beyond those usually expected during strong earthquakes. The improvements can be achieved with volumetric ratios of confinement steel that are typically used for normal-strength concrete columns, provided that higher grades of steel are used. Furthermore, analytical techniques commonly employed for analysis of normal-strength concrete columns can also be used for high-strength concrete columns, if proper material models are incorporated, reflecting stress-strain characteristics of high-strength concrete and reinforcing steel.