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Charles River Bridge
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Vital Statistics:
Location: Boston, Massachusetts, USA
Completion Date: 2001
Cost: $86.4 million
Length: 1,457 feet
Type: Suspension (cable-stayed)
Purpose: Highway
Materials: Steel, concrete
Longest Single Span: 745 feet

In September 2001, Boston, Massachusetts, will unveil its crown jewel -- the Charles River Cable-Stayed Bridge. The bridge will be the first of its kind ever built -- a "hybrid" cable-stayed bridge made of both steel and concrete. Two planes of steel cables will support the 745-foot-long, 183-foot-wide main span, and the side spans will be constructed of post-tensioned concrete.

Charles River Bridge
Click photo
for larger image.

The Charles River Bridge is being built within a congested transportation region in the city, an area that already houses Interstate 93 and the Massachusetts Bay Transportation Authority's (MBTA) Commuter Rail and Orange Line. In order to squeeze the bridge into such tight quarters, architects came up with a brilliant solution. They designed the bridge to be supported by two inverted Y-shaped towers. The legs of the concrete towers actually straddle the MBTA tracks at a 55-degree angle, allowing plenty of room for the Orange Line and its ventilation buildings.

When completed in 2001, the bridge will carry 10 lanes of traffic: eight through the legs of the two towers and two cantilevered off the east side. Not only is this design unique, it's practical as well. The asymmetrical design gave engineers the freedom to construct such an enormous bridge within inches of a major elevated highway without interrupting the flow of traffic.

Here's how this bridge stacks up against some of the longest-spanning bridges in the world. (total length, in feet)
Chart showing the relative size of the longest bridges in the world
Charles River Bridge 1,457'

Fast Facts:
  • Upon completion in 2001, the Charles River Cable-Stayed Bridge will be the widest cable-stayed bridge in the world.
  • It will also be the only asymmetrical cable-stayed bridge in the United States.

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