Confining reinforcement for high strength concrete columns
Date of Issue2004
School of Civil and Environmental Engineering
A comprehensive parametric study of reinforced high-strength concrete (HSC) columns is undertaken to verify the current ACI 318 and NZS 3101 code provisions of confining reinforcement in the potential plastic hinge regions of HSC columns. A full range of parameters that have significant influences on the available strength and curvature ductility factor in the potential plastic hinges of the columns during cyclic flexure are examined. These include the concrete compressive strength fc′ , the axial load level Pe/fc′ Ag, the yield strength of transverse reinforcement fyh, the volume ratio of the transverse reinforcement, the area ratio of the longitudinal reinforcement to the gross section area ρt, and the ratio of Ag/Ac. Previously derived stress-strain relationships for compressed HSC confined by various quantities, yield strengths, and arrangements of transverse reinforcement are used in cyclic moment-curvature analyses of a range of reinforced HSC columns to derive design equations. The proposed design equations are able to determine the quantities of transverse reinforcement required for the specified curvature ductility demands of HSC columns. The accuracy of the proposed design equations was checked by comparing with experimental data reported in previous literature, and a satisfactory correlation was found.
ACI structural journal
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