Prefabricated SFRC panels for occupant friendly seismic retrofit of reinforced concrete columns

In this study the behavior of reinforced concrete columns retrofitted with external jackets of prefabricated steel fiber reinforced concrete (SFRC) panels is investigated. The basic aim was increasing the ductility of existing columns using an economical and occupant friendly technique. For this purpose ten specimens representing the typical deficiencies of columns of existing reinforced concrete structures were tested under axial and reversed cyclic lateral loads. The main deficiencies were low quality of concrete and inadequate transverse reinforcement. As well as these deficiencies, five of the specimens had insufficient lap splice length problem too. Original specimens without any retrofit prematurely failed due to buckling of longitudinal bars or loss of bond between reinforcement and concrete. For the case of retrofitted specimens significant enhancement was obtained in strength and ductility. The enhancement in the behavior, particularly in terms of strength, was more pronounced for the specimens that did not have lap splice deficiency.