Rapid repair of RC bridge columns with prestressed stainless-steel hoops and stainless-steel jackets

Abstract

A fast repair method is developed for earthquake induced-flexure/shear damage at the bottom of the reinforced concrete (RC) columns. The method is a kind of hybrid jacket that employs a thin stainless steel jacket wrapped around the column and the outside stainless prestressed steel hoops. The prestressed steel hoops provide active confinement for the column and prevent premature buckling of the steel jacket. The stainless steel jacket provides confinement to the core concrete, and, as well as, prevent the prestressed hoops from penetrating the concrete to cause stress loss. A large-scale RC column was damaged during pseudo-static cyclic loads, firstly, and then repaired with this method as experimental validation. The pseudo-static cyclic test results from the original and repaired RC columns were compared for failure mode, hysteresis behavior, strength and stiffness degradation, ductility, energy dissipation, and damage status. The repair method was proved to be effective in restoring the structural behavior of the damaged columns to prevent bridge collapse. The ductility of the repaired specimens was 111.4% that of the original specimen; the lateral force capacity was 113.3% that of the original specimen. This repair method can be used to repair columns with repairable damage as an emergency repair, or construction method for new structures.