Residual flexural strength of corroded reinforced concrete beams

• FEA and analytical models to estimate residual flexural strength of corroded RC beams
• The models showed good agreement with the available experimental data
• The models incorporate critical parameters that weren’t considered in existing models
• If corrosion length < 60% of span length, it has no effect on ultimate strength
• If corrosion deg. > 40%, corrosion length has no effect on the ultimate flexural strength

In order to develop a cost-effective retrofit system for deteriorated concrete members, there is a need for sound evaluation of their remaining strength. Unfortunately, there is a lack of reliable models for evaluating the residual strength of steel reinforced concrete beams, and further, there is no simplified analytical model that can reasonably estimate the ultimate capacity of corroded reinforced concrete (CRC) beams. To address these issues, this research presents a new methodology for the evaluation of the residual flexural strength of CRC beams. Finite Element (FE), detailed, and simplified analytical models that account for damaged material properties and geometry, were developed and verified against the experimental data obtained by others. The detailed analytical model was employed to investigate the effects of corrosion degree, length of corroded zone, and span to depth ratio on flexural strength. This analysis showed that for beams with high corrosion degrees, the decrease in capacity is mainly because of the decrease in both the steel reinforcement cross-section and strength due to corrosion, whereas the major cause of strength reduction for beams subjected to low corrosion degrees is the loss of bond between steel and surrounding concrete.