Atmospheric corrosion-resistant steel, also known as weathering steel, has been utilised for the last thirty years in Switzerland, for the construction of various structures, in particular, steel-concrete composite bridges. Structures built using weathering steel do not require paint-type surface protection, because over the course of time, an oxidation resistant layer develops on the metal's surface.
Since their first appearance, structures built with weathering steel have not been made the subject of any sort of systematic review concerning the development of this layer. Fears originating at the time this type of steel first appeared regarding the possibility of over-development of the weathering layer, along with concerns relating to the general appearance of this type of structure, have not yet been totally eliminated, through lack of an exhaustive study on the subject under Swiss weather conditions.
The goal of this work will be to supply engineers and owners with objective information concerning the state of structures built with weathering steel after twenty or thirty years of weathering. This information will be based on observations of the state of existing structures, thickness measurements of the steel plates comprising beam sections, and experiences with weathering steel reported in surrounding countries.
The results of this work will also make it possible to set straight misconceptions concerning the use of weathering steels, determine factors affecting the development of the weathering layer, and recommend improvements to be made for the future in this domain. Proposals concerning maintenance and repair of bridges built with weathering steel will also constitute an objective of this study.
Creating a database of the behavior of bridges and establish recommendations for the use and maintenance of weathering steels in Switzerland.