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 un der different levels of constant axial compression and incrementally increa sing lateral deformation reversals. The columns had a circular cross sectio n and circular transverse reinforcement. Different volumetric ratios and gr ades of steel were used to confine the core concrete. The results indicate that the deformability of high-strength concrete columns can be improved si gnificantly through confinement. Inelastic drift capacity of columns can be improved to levels well beyond those usually expected during strong earthq uakes. The improvements can be achieved with volumetric ratios of confineme nt steel that are typically used for normal-strength concrete columns, prov ided that higher grades of steel are used. Furthermore, analytical techniqu es commonly employed for analysis of normal-strength concrete columns can a lso be used for high-strength concrete columns, if proper material models a re incorporated, reflecting stress-strain characteristics of high-strength concrete and reinforcing steel.