The seismic retrofit technique of RC column utilizing pre-tensioned high-strength steel bar (so-called PC bar) was proposed by Yamakawa and Kurashige et al., and it was verified that the seismic performance of poor RC column could be improved by using this seismic retrofit technique. However, axial compression behavior of RC column confined by pre-tensioned PC bar has yet to be investigated. In this paper, results of axial compression tests of RC columns with active and passive confinement are described at the first phase, and then, Sakino & Sun's stress-stain model of confined concrete is modified in order to evaluate experimental results appropriately.
