Experimental evaluation of FRP jackets in upgrading RC corroded columns with substandard detailing

Reinforced concrete columns designed and built prior to the introduction of modern detailing practices are often susceptible to the compounded influences of reinforcement corrosion owing to carbonation or exposure to the marine environment, a circumstance that decimates even further the limited safety reserves of old-type construction. This problem was witnessed repeatedly during the recent earthquakes in Southern Europe. In this paper, the structural behavior of corrosion-damaged columns with reinforcement details representative of pre-1980s Codes of practice was studied through an experimental program comprising 21 prismatic specimens. Columns were upgraded by means of FRP jacketing after being conditioned to accelerated electrochemical corrosion, and were subsequently tested to failure under concentric compression; some specimens were subjected to a repeated cycle of corrosion conditioning after jacketing and prior to mechanical testing. Primary variables of the investigation were the jacket characteristics and the repair method applied. Parameters used to gauge the performance of the upgrade were, the efficacy of the jacket in recovering the strength and in enhancing the deformation capacity of the columns, as well as in slowing down the depletion of reinforcement during the post-repair corrosion cycle.