17 Feb Weathering Steel Bridges
Have you spotted a rusty-looking bridge in your community or while traveling? From pedestrian bridges to highway bridges, corten-equivalent weathering steel is often used as an alternative for bridge construction. While conventional steel bridges take advantage of the latest advances in automated fabrication and construction techniques to provide economic solutions, weathering steel bridges offer further benefits.
The benefits of using weathering steels for bridge construction
Weathering steel offers practical advantages over other metals for structures that are exposed to the elements, such as bridges. Weathering steel…
- Is corrosion-resistant: Due to its chemical makeup, weathering steel forms a protective rust patina that prevents corrosion in suitable environments.In fact, the corrosion rate is so low that bridges fabricated from unpainted weathering steel can achieve a 120-year design life with minimal maintenance.
- Blends well in outdoor environments: The unpainted appearance of weathering steel blends well in gardens, backyards, parks, and other outdoor environments where bridges are required. Initially, weathering steel bridges appear orange-brown, but as the patina begins to form the color improves with age into a darker brown.
- Eliminates the need for site painting: By eliminating the need for site painting operations, using weathering steel in bridge construction reduces the duration of construction.
- Requires minimal maintenance: Periodic inspection and cleaning should be the only maintenance required to ensure the weathering steel structure continues to perform well. This characteristic makes weathering steel ideal for bridges where access can be difficult and disruption needs to be minimized.
- Is a cost-effective alternative: The minimal maintenance requirement along with the elimination of painting greatly reduces bridge construction cost. In fact, the cost of using weathering steel for bridge construction is about 5 percent lower than using conventional painted steel.
All in all, weathering steel has a proven track record. A study by TRL indicated that bridges built with weathering steel over the last 20 years continue to perform well.
Bridge construction products
ASTM A847 hollow structural sections are commonly recommended for bridge and railing applications. With hollow structural sections, you need less steel to do the same job. ASTM A847 is commonly used for bridge applications along with light/utility poles, sign supports, and building construction. Central Steel stocks high-strength, corrosion-resistant steel pipe and tube in a variety of sizes.
About weathering steel
Weathering steels are a family of ASTM specifications and several trademarked specifications exhibiting similar corrosion-resistant properties. The ASTM specifications are A588, A242, A606-4, A847, A871-65 and A709-50W. The primary trademarked weathering steel product is Cor-ten®. After Cor-ten® gained popularity, other producing mills began to develop their own atmospheric corrosion resistant steel. Consequently, ASTM created what is considered equivalent specifications to Cor-Ten® in most applications. The applicable equivalent ASTM specifications are ASTM A588, A242, A606-4, A847 and A709-50W, which Central Steel Service has in stock.