Behaviour of high-strength concrete columns confined by spiral reinforcement under uniaxial compression

- 18 HSC columns confined by spiral reinforcement were tested to investigate the factors influencing behaviour of confined concrete, including strength of concrete, spacing of transverse reinforcement and specimen height.
- The specimen height to core concrete diameter ratio ranges from 2 to 4.
- Four stress-strain of confined concrete models were compared with the experimental results.

This paper presents the results of an experimental program investigating the behaviour of confined high-strength concrete. Eighteen high strength concrete circular columns confined by spiral reinforcement were tested under axial compression. The test variables included concrete compression strength, the spacing of the spiral reinforcement and specimen height. The influence of the size of the effect on the behaviour of the confined concrete was investigated. Four confined concrete models which are defined in the literature were used to predict peak stress and strain of the core concrete (Mander et al., 1988; Fafitis & Shah, 1985; Razvi & Saatcioglu, 1999; Legeron & Paultre, 2003). A comparative study of the stress-strain model with the test results indicated that the models used in this study all produced a conservative prediction for the ductility of confined high strength concrete. The model proposed by Fafitis & Shah 1985 can make a more accurate prediction with standard deviation 3.92% and 21.88% in peak stress and strain, respectively, compared to predictions made by other models.