Seismic performance of severely corroded RC columns strengthened with HSECC jacketing: Quasi-static tests and numerical simulation model

This study investigates the seismic strengthening performance of severely corroded reinforced concrete (RC) columns using high-strength engineered cementitious composites (HSECC) combined with different lateral confinement methods. Ten cantilever columns were tested under cyclic loading at axial compression ratios of 0.1 and 0.3. For each axial compression ratio, five specimen configurations were examined: uncorroded, severely corroded, and three strengthened specimens using HSECC alone, HSECC with internal high-strength stainless steel wire ropes (HSSSWR), and HSECC with external fiber-reinforced plastic (FRP). The results show that HSECC strengthening effectively restored both load-carrying capacity and deformation capacity, and shifted the failure mode of corroded columns from shear-dominated to flexural-dominated behavior. Additional transverse confinement further enhanced the strengthening effectiveness. Under a low axial compression ratio, the cumulative energy dissipation of HSECC-FRP specimens increased by 744% compared to the corroded specimens, with a ductility coefficient of 6.34. Under a high axial compression ratio, the cumulative energy dissipation increased by 3632%. Although internal HSSSWR confinement effectively controlled longitudinal reinforcement strain, its energy dissipation capacity was lower than that achieved by external FRP confinement. Based on the experimental results, a fiber element model was developed in the OpenSEES platform, incorporating corrosion-induced degradation of steel reinforcement, the tensile strain-hardening behavior of HSECC, and the confinement effects of transverse reinforcement. The numerical results show good agreement with both the present experiments and data from the literature. Finally, a parametric study was conducted to evaluate the effects of corrosion ratio, axial compression ratio, confinement parameters, and HSECC strength on the seismic performance of strengthened columns. The findings of this study can provide an important theoretical basis and technical reference for the seismic strengthening design of corroded structures. • HSECC-based seismic strengthening for severely corroded RC columns was experimentally validated. • HSECC restored strength and deformation capacity, shifting failure from shear to flexure. • HSECC with FRP or HSSSWR confinement significantly improved ductility and energy dissipation. • An OpenSEES fiber model accounting for corrosion, HSECC hardening, and confinement was developed.