CONTRIBUTION OF STEEL FIBERS ON DUCTILITY OF CONFINED CONCRETE COLUMNS

Displacement and curvature ductilities are the key parameters in the design of structural columns because columns are very important structural members for the strength and resilience of a building. To increase column ductility, one common approach is by providing confinement. The number of reinforcing bars and its confitheiration commonly became the main parameters studied by researchers. The outcomes showed that columns were able to reach high lea vel of ductility (mu(delta)> 6) by using heavy transverse reinforcement and specific detailing. Another approach to improve the column ductility is by applying steel fiber to the concrete to increase the stress and the strain behavior of concrete. These two approaches are combined and studied in the experimental tests presented in this paper. The confinement and fiber used in the reinforced concrete specimens were square stirrups and steel fiber with volumetric ratio V-f ranging 0-2%. from All columns were subjected to quasi-cyclic horizontal load at the column top until reaching failure at about at 0.80P(h-max). An axial load of P(a )about 12% axial load capacity is maintained throughout the test. This study indicated that fiber could contribute to extend the inelastic displacement of the column so that the specimen can reach a high ductile displacement ductility, especially in columns with a ratio of V-f=1%.