Influence of Non-uniform corrosion of steel bars on the seismic behavior of reinforced concrete columns

Corrosion of reinforcing steel bars is a major factor in the degradation of the seismic performance of reinforced concrete (RC) structures. In this work, a pseudo-dynamic test was carried out on six corroded square RC columns with different axial compression ratios and corrosion levels. The hysteresis curve, skeleton curve, ductility and energy dissipation of the RC columns were compared and discussed. The influence of the non-uniform corrosion of the reinforcing steel bars on the seismic performance of the RC columns was analyzed accordingly. The results show that with the increase of the corrosion level the energy dissipation significantly decreased, whereas the ductility ratio was slightly increased, indicating the corrosion of the steel bars seemingly improved the ductility of the columns. The non-uniform corrosion had led to the significant difference in the post-peak behaviors of a RC column under the positive and negative loadings. Two different failure criteria of bilateral and unilateral failure criteria were thus proposed to address this difference. It was found that the seismic performance of the corroded RC columns evaluated by these two failure criteria differed greatly. The bilateral failure criterion had overestimated the seismic performance, while the use of the unilateral criterion can better reflect the effect of non-uniform corrosion.