STRUCTURAL PERFORMANCE OF REINFORCED-CONCRETE COLUMNS WITH DIFFERENT GRADE LONGITUDINAL BARS

A new reinforcing method to improve the inelastic behavior of reinforc ed concrete columns is proposed The method combines use of high-streng th and ordinary strength longitudinal bars. When the column is subject ed to bending moment, the ordinary strength longitudinal bars yield fi rst and then the high-strength bars yield later in large post-yield ra nge. Up to the stage of yielding of the high-strength bars, the column does not show significant degradation of load-carrying capacity To co nfirm the advantages of the new reinforcing method, flexural analyses on reinforced concrete columns with different grades longitudinal bars were conducted. The results of the analyses indicate that the combine d use of different grades of longitudinal bar improves the inelastic b ehavior of reinforced concrete columns.