Deformation limits of corroded reinforced concrete columns

Abstract

Steel reinforcement corrosion is one of the main causes of the mechanical degradation of reinforced concrete (RC) members. Selecting proper performance indexes and quantifying their limits for structural components is an important issue in the life-cycle performance-based seismic design. In this study, the damage levels of flexure-dominated RC members are defined mainly based on the material strain. The mechanical and deformation behavior of corroded RC columns are analyzed by numerical simulation performed with Abaqus software. The corrosion ratio, the axial compression ratio, the longitudinal reinforcement ratio, the stirrup ratio and the shear-span ratio are considered in the parametric analysis. It is found that the performance of slightly corroded columns is approximate to that of noncorroded columns, although the deformation capacity significantly degrades if the column corrosion is severe. An increase in the axial compression ratio leads to a decrease in the deformation capacity of RC columns. Increases in the longitudinal reinforcement ratio and stirrup ratio are beneficial to improving the deformation capacity of slightly corroded columns but have little effect on the ultimate deformation of severely corroded columns. According to the numerical results, formulas of the yield and ultimate deformation of corroded RC columns are derived, and the deformation limit of each damage level are proposed, which can both be applied in the life-cycle performance-based seismic design and assessment of RC structures.