The Hood Canal Floating Bridge is an important link along State Route 104 connecting the Seattle-Tacoma area with the Olympic Peninsula of westernmost Washington. History of the bridge dates back to 1959 when construction on the original structure began. It opened for traffic in 1961, with a length of 1 1/2 miles. The floating portion of the two-lane bridge measures 7450 feet, making it the longest floating bridge in saltwater in the world.
However, the west half of the bridge sank into more than 300 feet of water during a severe storm in February 1979. It was reopened to traffic by 1982. But by 1997 the state decided that the east half had reached the end of its service life and needed to be replaced or refurbished.
Work on the current project took awhile to get going, though by 2005 the approach spans had been replaced. Work on the pontoons and concrete anchors were located at the Port of Tacoma.
Construction proceeds in eight-month cycles, says Rich Whitlock, Kiewit General's concrete superintendent, the lead contractor on the project. Three or four pontoons are built during each cycle.
Once a cycle is completed, the dry dock is flooded and the pontoons are floated out for a tugboat ride north to Seattle, where the superstructure and the roadway deck are added. From there the completed pontoons are floated around the Puget Sound to the bridge site.
Three of the east side pontoons also are being retrofitted at the Seattle site and will be reassembled along with the new pontoons during the summer of 2009.
For detailed information on the bridge construction, including time-lapse Web cam photography, visit www.hoodcanalbridge.com.
This article is part of our October "Tools for the Concrete Pro" series. You can read other articles in the series by clicking the links below