Failure mode transitions of corroded deep beams exposed to marine environment for long period

• Four 28-year-old deep beams: two corroded and two control have been tested in 3-points bending.
• Corrosion results of natural process and then corresponds to in-situ conditions.
• Corrosion lead to failure mode transitions.
• Natural corrosion allows keeping a sufficient anchorage of corroded tensile bars.

This paper presents an investigation of the residual structural response of corroded, deep, reinforced concrete (RC) beams. A three-point loading test was carried out on two corroded deep beams that had been stored in a natural corrosive environment for 28 years. Two uncorroded beams with the same steel configuration and span were tested to understand the impact of corrosion on the residual mechanical performance of the deep beams. The distribution of corrosion and gravimetric cross-section loss of the tension bars were measured. The corroded tension bars were extracted from the beams to study the residual mechanical properties. The load-bearing capacities of the corroded beams were assessed using the measured mechanical properties and the residual cross-section of the bars according to different failure mechanisms. The results show that, in this case, the corrosion of steel reinforcing bars could change the failure mode of the reinforced concrete beams from shear to flexure.