On January 22, 1997, the State Route 509 cable-stayed bridge over the Thea Foss Waterway opens to traffic. It is one of only 13 such bridges in the nation and is part of a $165.3 million project that connects Interstate 5 to downtown Tacoma. The artery will be an important feature in the renaissance of the city.
The twin towers of the bridge are 180 feet tall and the two spans totals 707 feet. The unusual design was first suggested in 1991 by architect Jim Merritt who approached Tacoma Mayor Karen Vialle. Merritt wanted to see something more interesting than the design planned by the State Department of Transportation. U.S. Representative Norm Dicks was enlisted in the plan for a better design and he helped convince state officials to consider Merritt’s idea. Tacoma offered to pay for any additional costs of the new bridge, but the project came in under budget.
The decks of cable-stayed bridges are steadied or even supported by cables hung straight down to the deck from masts or pylons. Cable-stayed bridges differ from suspension bridges, which have horizontal cables hung like clotheslines between the towers, one on each side. Vertical suspenders hanging from the horizontal cables support the deck of the suspension bridge. Cable-stayed bridges are not new in concept, but the earliest examples were not built until after World War II.
State Route 509 and the cable-stayed bridge were built to provide an alternate route to E 11th Street, which ran straight through the industrial tideflats across the Blair Waterway Bridge and the Murray Morgan Bridge into downtown Tacoma. The new route more or less loops around the tideflats. It was built so that the Port of Tacoma could develop Blair Waterway, first by taking down the old and too-narrow 1953 Blair Waterway drawbridge, and next by dredging the waterway, which runs parallel to Thea Foss Waterway.
Residents of northeast Tacoma were particularly dependent on the Blair Bridge and to settle the years of debate and conflict over demolishing it, WSDOT and the Port of Tacoma agreed that SR 509 and the new cable-stayed bridge would be completed first. The day after the new route opened, construction crews began taking out the Blair Bridge and the dredging of the waterway began soon after. These infrastructural adjustments enabled the Port of Tacoma to undertake major improvements and expansions of port facilities.
