Effect of pre-damage on compressive properties of circular RC columns repaired with BFRP composites: Testing and modeling

Abstract

In reinforced concrete (RC) structures, structural members with damage should be repaired before reuse. Unlike existing studies that focus on strengthening of undamaged RC columns, the present study focused on the compressive properties of pre-damaged RC columns repaired with basalt fiber reinforcement polymer (BFRP) composites. Twenty-two circular columns with a relatively large size were tested. The influence of pre-damage levels, number of BFRP layers, and steel rebars on the compressive properties of the repaired RC columns were investigated. The test results showed that repairing with BFRP increased the strength and ultimate strain of the pre-damaged RC columns by 26–142% and 574–1147%, respectively, compared to the plain concrete counterparts. However, the axial stiffness and compressive strength of the repaired pre-damaged RC columns decreased as the pre-damage level increased. Addressing the adverse effect of pre-damage and the contribution of steel rebars, a strength model, ultimate strain model, and stress–strain relationship model were proposed to predict the compressive responses of the BFRP-repaired RC columns. The proposed models predicted well the test results. This study demonstrates that BFRP repairing is effective in enhancing the compressive strength and deformation capacity of damaged RC columns, even though the pre-damage level is severe.