2010 Top 10 Bridges - No. 3

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HURRIEDLY YOURS - Lake Champlain Bridge built with speed and consensus


PROJECT: Lake Champlain Bridge
LOCATION: Chimney Point, Vt., to Crown Point, N.Y.
OWNER: New York State DOT
COST: $80 million
Speed is of the essence in constructing the replacement of the Lake Champlain Bridge.
The 80-year-old bridge was an important commuter route for residents on both sides of the lake, and there is no convenient substitute. About 3,400 vehicles made the crossing on an average day. When the bridge was found to have significant deterioration of its concrete piers and closed in October 2009, the two states involved, New York and Vermont, hurried to build a new dock and set up a free ferry service.
In December 2009, the old bridge was demolished. Because of the effect of the loss of the bridge on the local economy and the everyday lives of the local residents, construction of the replacement bridge is on what HNTB described as “an extremely expedited schedule.”
Preliminary design began in December 2009, and the design was fi nished in April 2010. The new bridge should open to traffic in fall 2011.
The new Lake Champlain Bridge will be a signature network tied arch span, with steel-girder approach spans and concrete piers. The arch will be 402 ft long, sitting on triangular rigid frames that flank the arch span, and the entire bridge will be 2,200 ft long.
Constructability played a big part in the design process. To expedite construction, the arch span will be constructed off-site concurrent with the steel-girder approach spans. Once the arch span is completed, it will be floated to the bridge site and lifted as a whole into place.
The deck of the arch span also will be constructed off-site in the form of precast concrete panels. Once the arch span is in place, the deck panels can be installed relatively quickly.
Another major part in designing the new Lake Champlain Bridge—and a factor in expediting the approval process—was enlisting the public in delivering the most desirable bridge. A public meeting in December 2009 allowed the local residents to vote for their favorite of six concepts for the new bridge.
Aesthetics were an important part of the bridge design. The bridge’s color, lighting, height and appearance were considered by the designers, owners and public.
Residents also made their voices heard on issues such as lane and shoulder widths for farm equipment, vertical clearance, navigational clearance for boat traffic and inclusion of sidewalks. A variety of “consulting parties” were involved in the design process. The parties included historical groups, environmental groups and government agencies.
The landscape on both sides of the lake is rich in archaeological resources. Artifacts dating back tens of thousands of years have been found near the bridge site. To disturb as little previously undisturbed ground as possible, the new bridge is being built at the same site as the old bridge. Pile locations were carefully selected to minimize soil disturbance.
The builders will monitor nearby historic structures for construction-related vibrations. They don’t want to damage the historic structures and create a situation that might slow progress toward a new Lake Champlain Bridge.
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