|Grand Award - Construction|
|Highway and transportation|
and east-half replacement
Location: Shine, Jefferson County
Kiewit-General Joint Venture, over six years, replaced the east half of the Hood Canal Bridge — the longest floating bridge over saltwater in the world — and updated parts of the west side, making the bridge wider and safer.
Building floating bridges is a narrow specialty that requires unique knowledge and experience. Of the 11 floating bridges in the world, four of them are in the Puget Sound area.
One challenge was joining individual pontoons and constructing the elevated roadway, buildings and draw span machinery. The work was performed on buoyant foundations floating in seawater. Survey control for these operations involved an inventive adaptation of 3-D/3-point resection survey software that does not use the earth’s gravity for a reference vector.
New reinforced concrete anchors, weighing as much as 2,000 tons, were built off-site. Once at the bridge site, the anchors were accurately positioned on the ocean bottom in seawater up to 350 feet deep before being weighted in place with rock ballast.
All the equipment used to grip and lower the massive anchors was designed and fabricated especially for the project. Accurately positioning the anchors on the sea bottom involved innovative uses of instruments, including slope indicators and gyrocompasses that are normally used in other applications.
Kiewit-General completed the bridge ahead of schedule, earning commendations from state Transportation Secretary Paula Hammond at the opening ceremony for the bridge:
“This is a huge accomplishment for our project team and Kiewit-General, who overcame some tremendous engineering challenges to reopen this vital link to the Olympic Peninsula.”
Copyright ©2010 Seattle Daily Journal and DJC.COM.
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