Seismic Retrofit of RC Circular Columns Using Prefabricated Composite Jacketing

TLDR

The study investigates seismic retrofitting of reinforced concrete circular columns with poor lap‑splice details using prefabricated composite jacketing. The authors tested 1:2 scale model columns—one as‑built and two retrofitted—and developed an analytical model that incorporates bond‑slip deterioration of lap‑spliced bars. The as‑built column failed brittlely due to deteriorated lap splices, whereas the retrofitted and repaired columns showed markedly improved seismic performance and ductility.

Abstract

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.