Parametric study on contribution of combined confining steel and steel fiber to column’s displacement ductility

This study examines the contribution of confinement with variations in spacing sh = (50, 65, and 80) mm and concrete reinforced with steel fiber to displacement ductility. Eight test column specimens (No. 1, 2, 3, 6, 7, 8, 11, and 12) were also reinforced with stirrups according to ACI 318M:19 provisions while four test column specimens (No. 4, 5, 9, and 10) deliberately reinforced with a slightly wider spacing of stirrups with different yield strengths (fy) (lower than the code requirements). However, the volumetric ratio of the steel fiber was varied, i.e. Vf = 0%, 0.5%, 1%, 1.5%, and 2%. The column was then subjected to a quasi-cyclic and a constant axial load of Pa = 0.121.Ag.fc'. The test results indicated that all test column specimens could attain the full ductile/fully ductile criteria since µ∆>4. When the drift ratio required by ACI 318M-19 is observed, the use of combined confining stirrups and steel fiber works together simultaneously to achieve a drift ratio capacity that exceeds the minimum required target of 3%, meaning that the columns could perform satisfactorily.