This paper shows how the corrosion and mechanical actions can be taken into account in a simple model for the assessment of structural elements. This work is framed in the Project Benchmark des Poutres de La Rance in which several partners have participated. The Project tried to characterize the degradation of reinforced and prestressed concrete structures after an aging in marine atmosphere with non-destructive methods and to evaluate different existing models for the structural assessment. For this aim a 4-point bending test was performed on six prestressed concrete beams. The model gives a reasonable approach for the assessment of structural elements. Similar rules can be adopted for other failure modes. It is important to notice the need of reliable input data for the assessment and also the need of integration of deterioration processes in design.