After months of delays and an additional $179 million, Washington State’s Hood Canal Bridge reconstruction reached 80% completion this month with the completion of the last pontoon sections for a new eastern half.

Washington State DOT A new Hood Canal bridge section heads to Seattle to receive systems outfitting.

A joint venture of Kiewit Pacific Co., Vancouver, Wash., and General Construction Co., Poulsbo, Wash., on Aug. 1 floated the last two of 14 pontoons out of a graving dock in Tacoma for a trip to Todd Pacific Shipyard in Seattle. Electrical and mechanical systems will be added there in preparation for a six-week final installation at the site of the 7,869-ft-long bridge next spring.

The post-tensioned pontoons are rectangular concrete boxes filled with empty cells, rebar and mechanical and electrical equipment. The last two pontoons are each 18-ft tall, 60-ft wide and about 340-ft long.

The pontoons were built in a 150-ft-wide, 465-ft-long graving dock owned by Concrete Technology Corp. The day they were completed, workers from Foss Tug, Seattle, opened a hole in the gate, allowing water to fill the dock and the approximately 6,000-ton pontoons to float. Tugboats took them 35 miles to Seattle.

The original dry dock being built in Port Angeles had to be abandoned when Native American remains and artifacts were discovered .The project shut down for over 15 months. The incident caused “a lot of political turmoil,” says Jeff Swett, senior bridge engineer with WSDOT. “We decided to suspend the original contract, pay everyone in full and renegotiate to a target price.” The $292 million project is now about $471 million. The joint venture’s original $204 million contract is now $347 million.

Washington State DOT Last two floating pontoon sections leave graving dock.

The old western half of the Hood Canal Bridge, one of only 11 permanent floating bridges in the world and the longest over salt water, sank in 1979 after a storm. Tidal variations are as much as 16 ft a day. Winds can top 40 mph.

Parsons Brinckerhoff, New York City, completed plans for the eastern half replacement in 2003. PB’s bridge engineering director Michael Abrahams had worked on the western half replacement in the early 1980s. Three pontoons from that job were saved for the anticipated eastern half, in addition to the 14 new pontoons. “All along, we knew the east half had a remaining life of about 20 years,” he recalls. “In 1988, we were retained by WSDOT to update the plans and proceed.”

As traffic increased to 15,000 vehicles per day, WSDOT wanted to widen the two-lane bridge to accommodate wider lanes and shoulders. Designs had to be revised to allow for the extra loads, says Abrahams. Funding issues also delayed the start of eastern-half replacement work until 1997. Opening is slated for 2010.

For the new east half, “we borrowed a lot of technology from the oil industry,” says Becky Hixson, a WSDOT spokesperson. “The steel used in the [transition] trusses is round, as on oil derricks, so that water doesn’t collect on the surfaces and cause corrosion. An inspector with expertise in the oil industry flies in from Dallas just to inspect the welds.”