Effect of corrosion severity on the ultimate strength of a steel box girder

The objective of this paper is to analyse the ultimate strength of ageing ship structures based on experimental and numerical assessments. Three experimental ultimate strength tests have been carried out on box girders under vertical bending moment and several effects have been detected due to corrosion. Extensive nonlinear finite element analyses have been performed to compare the numerical and experimental results. The ultimate bending moment of corroded box girders has been compared with existing formulas. A relationship to calculate the equivalent tangent modulus as a function of the total reduction of the cross-sectional area due to corrosion degradation has been proposed. A new stress–strain relationship has been developed, taking into account the residual stresses and the corrosion effect, which may be directly used as a master stress–strain curve for a non-linear finite element analysis.

► The ultimate strength of ageing ship structures are made based on experimental and numerical assessments. ► Extensive nonlinear finite element analyses have been performed. ► The ultimate bending moment for corroded structures has been compared with existing formulas. ► A relation for the equivalent tangent modulus as a function of the thickness reduction has been proposed. ► A new stress–strain relationship has been developed.