The Boston Central Artery/Tunnel Project is the largest and most complex urban transportation project ever undertaken in the United States. Dubbed the "Big Dig" by Bostonians, it is the result of more than 30 years of planning and 12 years of construction to replace the elevated section of Interstate 93 Central Artery through downtown Boston with a much wider underground highway and to extend the Interstate 90 turnpike to Logan Airport via a third harbor tunnel. Among the only other transportation projects on this large a scale were the Panama Canal and the Channel Tunnel.
The project comprises 161 lane-miles of interstate highway--over half of it underground. Its host of civil engineering firsts include the world's widest cable-stayed bridge, the deepest underwater connection in North America, state-of-the-art freeway segments built only inches above 19th century public transit railways, and an unprecedented ground-freezing program to stabilize Boston's historic soils during construction. The project has been widely recognized through dozens of awards for engineering excellence and aesthetics.
The Leonard P. Zakim Bunker Hill Bridge is one of the widest cable-stayed bridges ever built. It floats above the Charles River as part of the Big Dig, the largest overall highway construction project in the United States. Bechtel served as management consultant in a joint venture with civil design firm Parsons Brinckerhoff.
In 2004, the American Society of Civil Engineers (ASCE) awarded the bridge its Outstanding Civil Engineering Achievement award.
Boston is already becoming known for its new bridge. Atlanta and other cities have requested similar designs. Swiss bridge designer Christian Menn won approval for his willowy cable-stayed bridge, a design that ties cables from the roadbed directly to the support towers. Asymmetrical, it carries two outer lanes cantilevered on its east side. An additional eight lanes pass through the legs of the twin 91-meter, obelisk-topped, inverted Y towers which echo the nearby Bunker Hill Monument. The 10-lane, 56-meter-wide structure picks up Interstate 93 traffic as it emerges from the new Central Artery tunnel and carries it across the Charles River to points north.
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Cleaning Up From Boston's Big Dig
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Boston's 14.8B Big Dig Finally Complete
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Lessons of Boston's Big Dig
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How the Big Dig is Transforming Boston (See P. 12)
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Don't let Big Dig scandals obscure great achievement
Dec 12, 2006
Big Dig roads are safe, says Romney
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Dig the Big Dig
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