• Journal of the Korea Concrete Institute
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• v.13 no.3
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• pp.261-267
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• 2001

The objective of this experimental study is to find the allowable level of axial load to give the proper flexural ductility according to the yield strength of lateral ties, and the distribution and amount of longitudinal bars used in confined high-strength concrete columns. Twelve concrete columns with a 20 cm square section and 80 cm high were tested under hi-axial loads. It was observed that the ductility tends to be improved at the axial loads not less than 0.4f$\_$ck/A$\_$g/. The utilization of high-strength ties in accordance with the ACI 318-99 can cause the brittle failure due to the wide tie spacing. Under the high level of axial loads not less than 0.4f$\_$ck/A$\_$g/. it is necessary for the buckling prevention of the longitudinal bars and the proper ductility improvement to use the high-strength ties with the consideration of the volumetric ratio and confinement type of the lateral ties, and the distribution of the longitudinal bars.