Seismic performance of corroded reinforced concrete beam-column joints repaired with BFRP sheets

Abstract

Reinforcement corrosion is one of the main reasons for the deterioration of reinforced concrete (RC) structure. Corroded RC beam-column joint experiences large deformations under the earthquake, which results in the deterioration of the seismic behavior. Although researches on the uncorroded joints strengthened with fiber-reinforced polymer (FRP) sheets have been conducted, investigations on the corroded RC beam-column joints repaired with basalt FRP (BFRP) sheets are relatively limited. In present research, seven interior beam-column joints were tested under the cyclic loading, including one reference specimen, three specimens with different corrosion rates, and three corroded specimens repaired with BFRP sheets. The seismic behaviors in terms of crack pattern, failure mode, hysteretic curve, load bearing capacity, deformation capacity, energy dissipation, and stiffness degradation were discussed. Results obtained from the test showed that: (1) the seismic behaviors of corroded beam-column joints were effectively improved by the utilization of BFRP sheets; (2) the spalling, and crushing of concrete, as well as the buckling of stirrups were delayed by the utilization of BFRP sheets; (3) the load bearing capacity, ultimate displacement, and energy dissipation capacity of corroded beam-column joints were effectively increased, and the stiffness was fully recovered to that of uncorroded joint by repairing with BFRP sheets; (4) the bond behavior between corroded bars and concrete or strains of corroded bars in beam-column joints were improved or decreased after repairing with BFRP sheets.