Tacoma could play a lead role in the multibillion-dollar project to replace Seattle's state Route 520 floating bridge over Lake Washington.
Survey crews from the Washington State Department of Transportation are probing, testing and measuring six tracts on the Tacoma Tideflats this week. Their task is to determine whether those sites are suitable for construction of concrete floating sections of the new bridge.
Five of those sites are owned by the Port of Tacoma. The sixth site is a graving dock used by Tacoma’s Concrete Technology Corp. to build floating pontoons, breakwaters, bridges and docks.
The state would lease the space, but it was unclear Thursday what that might cost.
The state needs 77 pontoons for the new six-lane floating bridge. Thirty-three of those floating structures will be built at a site in Grays Harbor County. Tacoma could become the site for construction of the remaining 44 of the pontoons.
Two of the port sites are on the water, one just north of the Hylebos Bridge on East 11th Street and one adjacent to the Concrete Technology graving dock on the Blair Waterway south of East 11th Street.
Three port sites are inland but near East 11th Street.
Suanne Pelley, spokeswoman for the bridge construction project, said the bridge pontoons are small enough that they could be built on a landlocked site and moved to the water for barging or floating to Lake Washington.
The pontoons measure 100 feet long by 60 feet wide by 20 feet high.
“The Port of Tacoma could provide contractors with an optional location for building floating bridge pontoons,” said 520 program director Julie Meredith. “We have an aggressive schedule to open a new floating bridge to drivers in 2014. We want to provide maximum flexibility to the contractor who will be responsible for constructing the new floating bridge.”
Kiewit-General Joint Venture has a $367 million contract to build the first 33 pontoons in Grays Harbor County.
The department last month began the search for firms that meet qualifications to build the bridge and fabricate the remaining pontoons. Bids will be due next year.
The state will leave the decision where to build those remaining pontoons up to the winning bidder on the bridge construction project. Tacoma won’t be the only candidate. The state will be surveying sites in Olympia next week, and the Grays Harbor site is also in the running.
The new bridge and its approaches is a $4.65 billion project. The bridge will be funded in part by tolls and federal funds.
The bridge construction work could create hundreds of construction jobs for local workers if the pontoons are built on the Tideflats.
Concrete pontoons for the Hood Canal Bridge were built at Concrete Technology’s graving dock beginning in 2006 during reconstruction of the bridge’s eastern half. The Concrete Technology site was picked after an Olympic Peninsula site initially picked by the Department of Transportation was discovered to be the site of an ancient Indian settlement.