The third cycle of the Hood Canal Bridge pontoon work was completed in late February 2008 as pontoons V and X, and ZC and ZD were floated out of Concrete Technology Corporation (CTC) in Tacoma to Pier 66 in Seattle and Pier 6 at Todd Pacific Shipyards.
Pontoons V and X will connect the yet-to-be built cycle four pontoons and the rest of the eastern half of the bridge with the new transition span that will lead to Kitsap County. Meanwhile, once installed, pontoons ZC and ZD will complete assembly of the bridge’s new draw span.
The pontoons are massive by any respect and while they seem little more than hollowed-out concrete bricks weighing thousands of tons each, they must work in perfect concert to support 1.5 miles of columns, girders and roadway. Despite their enormity, pontoons ZC and ZD, for instance, will be retracted and extended as a part of the draw span assembly – which is the bridge’s most complex section.
The new pontoons by the numbers
- All 102 cells in pontoons V, X, ZC and ZD were vigorously inspected by WSDOT and Kiewit-General before they were floated out of the graving dock at CTC
- Five tug boats from Foss Tug were used to tow the pontoons out of the graving dock, a process which took about two hours. After they left the graving dock in Tacoma, pontoons V and X were transported to Pier 66 in Seattle for mooring, pontoons ZC and ZD were taken to Todd Shipyards in Seattle for additional outfitting. The entire process took about 10 hours
- Pontoons V and X are 180 feet long, 60 feet wide and are 21 feet, 6 inches and 18 feet tall, respectively. Each pontoon required 11 separate pours to ensure the 1,923 cubic yards of concrete required was properly placed. Pontoons ZC and ZD are 247 feet long, 60 feet wide and 21 feet tall.
- V and X tip the scales at approximately 7,962,000 pounds each, outweighing the 6,492,000-pound jumbo class Washington State Ferries MV Walla Walla and MV Spokane by 1,470,000 pounds apiece. Pontoons ZC and ZD weigh in at a whopping 7,458,000 pounds and 7,578,000 pounds, respectively.
- The new east-half of the Hood Canal Bridge is comprised of 17 pontoons. Fourteen pontoons will be built at the Concrete Technology graving dock -- V and X, ZC and ZD will mark 12 complete. Three pontoons from the 1980s are also being retrofitted in Seattle for the project.
- The east-half pontoon work for the Hood Canal Bridge Project is currently 75 percent complete, as the structures must still be assembled, tested, have the roadway and columns added, and have electrical, mechanical and, in some cases, hydraulic components installed.