Compressive behavior of corroded reinforced concrete columns strengthened with BFRP reinforced ECC in marine environment

Corrosion of reinforced concrete (RC) columns due to chloride ions in marine environments is a significant problem. Reinforcement technologies, such as the engineered cementitious composite (ECC)-fiber reinforced polymer (FRP) reinforcement technology, have proven to be effective measures to improve the compressive capacity of RC columns. However, the confinement mechanism and design formula for this reinforcement technology remain unclear. In this study, the compressive behavior of corroded reinforced concrete column strengthened with basalt fiber reinforced polymer (BFRP) reinforced ECC was investigated by numerical analysis, including the load-displacement curves, the confinement mechanism, the stresses distributions and the effect of key parameters. Additionally, a theoretical model was developed to predict the peak load of the strengthened column. The results showed that the corrosion of the longitudinal steel bar and the stirrup were respectively significantly weakened the compressive capacity and the deformation capacity of the strengthened column; The stress in the BFRP grid reached 10% of its ultimate stress under point B, and increasing the number of BFRP grid layer was found to be beneficial in delaying the load degradation in the softening stage; The theoretical model established in this study could accurately predict the peak load of the strengthened column.