Repair, flexural upgrading and seismic retrofit of RC columns with reinforced FRCC light jacket

An innovative repair, flexural upgrading and seismic retrofit solution consisting of a reinforced light jacket (i.e., 3–4 cm) made of Fibre Reinforced Cement Composites, FRCC coupled with a High-Performance steel reinforcement is proposed for existing reinforced concrete (RC) columns. The proposed solution consists in a FRCC light jacketing coupled with a High-Performance steel reinforcement that works both as anchorage system for the jacket and as additional transverse reinforcement (Reinforced FRCC light jacketing or RFRCC). The goal of the solution is to improve the columns resistance against the migration of aggressive agents and at the same time to increase its flexural capacity. The potential of the proposed solution is demonstrated on 6 full-scale RC columns experimentally tested under quasi-static cyclic loading. The RC columns under investigation are subjected to a seismic pre-damage before the application of the RFRCC jacket. Square and rectangular columns with smooth and deformed rebars are tested to assess the feasibility of the technique for the repair and flexural strengthening of existing deficient RC columns. The experimental results attest the high potential of the proposed technique in recovering and enhancing the flexural capacity, ductility and energy dissipation of seismically pre-damaged RC columns.