Don’t Close the Book on Elliott Bay Bridge

While our esteemed leaders (Gregoire, Sims, Nickels) appear to have settled on a deep-bore tunnel as their collective preference for replacing the Alaskan Way Viaduct, it seems fitting to pay homage to an idea that never made it off the cutting-room floor: the bridge over Elliott Bay.

Option No. 11, as it was known, was eventually deemed too costly and potentially harmful to the environment. For one thing, the bay is so deep that the bridge's footings would have had to be the "size of a football field," former Viaduct program spokeswoman and WSDOT consultant Emily Fishkin, whose last day on the project was December 23, said recently.

But one Burien architect says he's got a way around that. Roger Patten has a patent pending for buoyancy stabilized piers, ideal, he says, for a bay with a mud bottom that's covered with more than 200 feet of water. Instead of resting on supports lodged in concrete, the bridge would sit lightly on the sea floor, thanks to his new "floating foot" technology.

"The buoyancy supplied is enough to offset the load of the bridge and any external forces," Patten explains. "It's not susceptible to tsunamis or earthquakes, and is less expensive than most foundation systems."

The problem is that a bridge with such a foundation has never been built, though similar technology is used for stabilizing offshore oil rigs. Nevertheless, argues Walter Blair, a retired engineer who used to consult on oil-rig projects, Patten's buoyancy-based system should have been given a chance. "WSDOT rejected the [Elliott Bay Bridge] because they thought you would have to pour massive concrete footings," he says. "You wouldn't want to do that. [Patten's idea] is so gentle. It won't harm anything."

Fishkin says WSDOT considered some floating technologies for the bridge option, but that the problem, other than expense, is that they are untested.