Building Better Bridges
New copper alloys are poised to change the face of building bridgesA new type of steel is changing the way bridges are built, thanks to the addition of a tiny percentage of copper. In a novel process, copper is combined with iron at the molecular level to produce an exceptionally durable material. This modern alchemy results in an alloy that is easier to weld, more resistant to corrosion and weathering, and almost 40 percent stronger than commonly used structural steels.
While some alloys such as Architectural Bronze or Cor-Ten steel earn easy-to-remember monikers, to date, the steel-copper alloy is known only by its technical designation, ASTM A 710 Grade B High Performance Steel. Illinois recently became the second state to put the material to use by specifying it for bridge construction in the town of Lake Villa. Some 500 tons of the material went into the 430-foot bridge.
According to Timothy W. Martin, secretary of the Illinois Department of Transportation (IDOT), "Not only is this steel strong, tough and easy to fabricate, but it withstands the elements better than typical steel, meaning it doesn't have to be painted. This makes construction easier and will significantly reduce long-term maintenance costs." Martin estimates IDOT saved $300,000 by not having to paint the bridge.
Illinois was so pleased with its bridge that it recently applied to have the steel-copper alloy designated as the standard for bridge construction throughout the United States. If it wins the approval of the American Society for Testing and Materials (ASTM), and American Association of State Highway and Transportation Officials (AASHTO), all bridges here and elsewhere may one day contain an important copper component. Cu
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Also in this Issue:
- Got Copper (In Your Diet)?
- Copper Ions Keep Roofs Clean
- Heating and Cooling "Green" With Copper
- A Copper Dollar in Your Pocket
- Building Better Bridges