Rehabilitation of seismic-damaged reinforced concrete beam-column joints with different corrosion rates using basalt fiber-reinforced polymer sheets

Reinforcement corrosion and seismic damage considerably affect the seismic performance of reinforced concrete (RC) members. In present research, five RC beam-column joints were designed and tested under cyclic loadings. These joints included one reference specimen, one uncorroded specimen rehabilitated with basalt fiber-reinforced polymer (BFRP) sheets, as well as three seismic-damaged corroded specimens with corrosion rates of 0, 3%, and 9% rehabilitated with BFRP sheets. The seismic behavior of tested specimens, involving the hysteretic responses, ductility, and energy dissipation was discussed. Test results demonstrated that the seismic behaviors of seismic-damaged corroded specimens were effectually upgraded after being rehabilitated with BFRP sheets. The spalling and crushing of concrete, as well as the buckling of stirrups were postponed by the utilization of BFRP sheets, while ductile behaviors of rehabilitated specimens could be observed in the test. Besides, the ultimate displacements, final stiffness, and total cumulative energy dissipation of the rehabilitated specimens were considerably improved with the maximum increase of 14.9%, 16.7%, and 23.3%, respectively. Equations considering the influences of reinforcement corrosion, seismic damage, and FRP rehabilitation on the shear strength of the core area of RC joints rehabilitated with FRP sheets were proposed, and good agreements could be found between the theoretical and experimental results.