Seismic retrofit of RC circular columns using prefabricated composite jacketing

This paper describes experimental and theoretical studies on seismic retrofit of reinforced concrete circular columns with poor lap-splice details using prefabricated composite jacketing. Three 1:2 scale model columns have been tested. One column was tested under the condition of ''as built'' and two others were tested after being retrofitted using prefabricated composite jacketing. The as-built column suffered brittle failure due to the deterioration of lap-spliced longitudinal reinforcement without developing its flexural capacity or any ductility. The retrofitted columns showed significant improvement in seismic performance. The failed as-built column was retested after being repaired. The repaired column also demonstrated significant improvement in ductility. An analytical model, which takes into consideration the bond-slip deterioration of lap-spliced longitudinal bars, has been developed for seismic assessment and retrofit design.