Abstract
The weathering steel has a unique property of preventing rust by rust, and using unpainted weathering steel is important to reduce the life cycle cost of infrastructure. The following condition for unpainted weathering steel should be satis ed to prevent layer-like detachable rust on the surface of the steel : maximum amount of airborne salts density is less than 0.05mdd (mg/dm2/day) between girders. However a state of corrosion is different in the part of the bridge. Furthermore airborne salt density between girders cannot obtained by observation until completion of bridge. Accordingly, evaluation for quantity of airborne salt by numerical simulation is needed at each part of the bridge. This paper discusses the estimation of airborne salt around section of the bridge by comparison between numerical result and observation of airborne salt near the girder.
