In the vicinity of the seaside uncoated weathering steel is not recommended to bridges if the quantity of windborne salt is above the prescribed value. This value is based on the experimental data obtained in flat and open area. The quantity of windborne salt can be below the prescribed value if some mountains are located between the bridge construction site and the seaside. The numerical evaluation of windborne salt is introduced to expand the applicability of weathering steel to bridges. In addition the simulation around the bridge girder section is also introduced in order to prevent local rust caused by locally adhering salt.
