Strength assessment of a severely corroded box girder subjected to bending moment

• Ultimate vertical bending moment of a severe corroded box girder loaded by pure moment is studied
• New stress-strain relations model the effect of corrosion on mild steel mechanical properties
• comparisons of the FE results using the new stress-strain models, and the experiments are made
• Results support the newly developed stress-strain relationships for corroded structures

This work deals with the evaluation of the ultimate bending moment of a severely corroded box girder subjected to uniform vertical bending moment through a series of nonlinear finite element analysis. Two models of corrosion degradation have been adopted, one is an average general corrosion thickness reduction, and the other is the real thickness of the corroded plates. New stress–strain relations have been developed to account for the effect of corrosion on the flexural rigidity. To validate the new developed stress–strain relationships, a comparison between the finite element analysis results using the existing stress–strain models, the newly developed ones and the experimental test results of a severely corroded box girder have been conducted. The comparison showed a good agreement and supported the choice of the newly developed stress–strain relationships of corroded structures.