Experimental and numerical evaluation of the structural performance of corroded reinforced concrete beams under different corrosion schemes

The effect of steel corrosion on the structural performance of reinforced concrete (RC) beams is a complex phenomenon concerning all types of reinforcing steel (tension, compression, and shear reinforcement) which has not been fully investigated experimentally or through modelling. The parameters used in models have not been fully employed in the non-uniform corrosion of steel bar, the buckling effect of corroded compression reinforcement or bond slip at the steel to concrete interface due to the combined effects of longitudinal and shear reinforcement corrosion. The objectives of this paper are i) to experimentally investigate the effect of three corrosion schemes (tension reinforcement corrosion; tension and compression reinforcement corrosion; tension, compression and shear reinforcement corrosion) on the structural performance of RC beams through the investigation nine beams, each with dimension of 150 mm width, 200 mm height and 2100 mm length ii) to employ a finite element method (FEM) to model both the control and corroded RC beams in which non-uniform corrosion of steel bars has been modelled by varying the bar diameters and the locations of corrosion pits including the buckling effect of compressive reinforcing steel bar, iii) to propose a modified bond slip model at the longitudinal steel–concrete interface due to the combined effect of longitudinal and shear reinforcement corrosion. The experimental results show that the yield and ultimate strength of the RC beams reduced under the three corrosion schemes. The yield strength of corroded RC beams is affected by the tension reinforcement corrosion while the ultimate strength is influenced by both the tension and compression reinforcement corrosion. Shear reinforcement corrosion contributes to the reduction in flexural strength of the RC beams due to the reduction in confinement of concrete. The failure modes and the ductility of the corroded RC beams are influenced by the non-uniformed corrosion and its distribution along the steel bars. The proposed FEM demonstrates good correlation with the experimental results, with the difference in ultimate flexural strength from the FEM and the experimental test in the range of 0.1 % to about 4 % for small pitting corrosion beams and up to 10 % for critical pitting corrosion beams.