The first bridges were built with stone masonry, and since then a range of materials have been used to construct bridges around the world, including iron, concrete, and steel. Steel is now a popular choice for most large-scale bridges due to it’s high compressive and tensile strength. Steel is also very ductile, and it deforms a considerable amount before it bends, providing a clear indication that maintenance is required.
Despite steel already being a favored choice for bridges, there is always a need to improve. Weathering steel was developed in the 1930s with the initial use expected to be for the rail industry. While the steel is still used for rail, it is now widely adopted for the construction of bridges.
Weathering steel (also known as Corten steel) is a high strength low alloy steel, which boasts a high level of atmospheric corrosion resistance. This type of steel is an alloy of nickel, chromium, and copper, which provides the resistance properties against moisture and air.
While weathering steel has this high level of resistance, it still experiences the initial rusting process that can cause severe damage to other steels. However, the alloying elements within weathering steel produce a consistent and stable layer of rust that sticks to the steel, and this provides a layer of protection against moisture and air.
The protective layer that covers weathering steel gradually becomes a distinct orange color that is considered visually pleasing by many, as it often blends in with the environment.
Before 2001 the use of weathering steel for the construction of bridges was restricted to only be used on highways with over 7.5 m of headroom. Since this restriction was lifted, the use of weathering steel has increased significantly for the construction of bridges.
One of the major advantages of using weathering steel to construct bridges is that it requires a very low level of maintenance, which helps to reduce the overall cost of construction. Once the bridge is built, only periodic inspection and cleaning to ensure the bridge is still in a satisfactory condition. This is beneficial, as maintenance on large bridges can be dangerous.
The protective rust layer formed by weathering steel helps to reduce both the overall cost and speed of construction as painting is not required. Additionally, as no painting is required, the environmental damage associated with VOC emissions from paint coatings is eliminated.
Typically, bridges built with weathering steel can achieve a 120-year lifespan with minimal maintenance.
Weathering Steel from Masteel
Masteel is a global supplier of a range of weathering steel grades. Our products are available in a variety of plate widths and thicknesses, and we can provide a quick turnaround due to our in-house cutting and profiling services.