Abstract
In the present paper, the bi-axial cyclic loading tests of reinforced concrete columns (i.e., UN-SFRC columns) in which the boundaries between rebar and steel-fiber reinforced concrete are un-bonded in the plastic-hinged zone, have been performed under the different loading histories. The experimental data have been compared with those of previous experiments on RC columns that are respectively RC column, SFRC column and RC columns with the intermediate reinforcements. The buckling and breaking of rebar during cyclic loading have been examined and it has been found that the use of UN-SFRC column is effective against the breaking of rebar. Also, flexural strength and ductility of the different types of RC columns have been examined in details in the post-peak loading region. The buckling characteristics of re-bar, the progressive deterioration of core-concrete and the energy absorption capacities have been discussed during cyclic loading process. It has been found that the use of UN-SFRC column might be effective to make the plastic hinged zone of RC column more ductile, particularly for the column with large spacing of hoop tie, i.e., the spacing of 120 mm in the present study.
