Firstly, this paper presents a concentric loading test of reinforced concrete columns confined by rectangular ties. Test variables are concrete compressive strength ranging from 45 to 130MPa and tie yield strength ranging from 320 to 1300MPa. It was confirmed that the yield stress of transverse reinforcement was not reached for reinforced concrete columns using high-strength concrete or tie, and previous stress-strain models computing the lateral pressure with tie yield strength overestimate the maximum strength of confined concrete. A method is proposed to compute the stress in the transverse reinforcement at the maximum strength of confined concrete and a new stress-strain model has been developed. The model has been verified extensively against experimental data included columns with a wide range confinement parameters and shows good correlation with stress-strain relationships established experimentally.