This paper presents an experimental study of the behavior of reinforced concrete rectangular columns confined by rectangular ties under concentric loading. The study incorporates all the relevant parameters of confinement that have been observed to play important roles in column tests. These parameters include the concrete compressive strength, amount of confinement reinforcement, the tie spacing, the tie yield strength, longitudinal reinforcement distribution, the transverse reinforcement configuration and section geometry. Nineteen normal strength concrete rectangular columns with different concrete dimensions, different concrete compressive strength and confinement characteristics were designed, constructed and tested in this research. Significant gains in strength and ductility are recorded for the concrete core of well confined columns.