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Magnolia Bridge Replacement Project

From The Queen Anne News:

(Also in Magnolia News)

Sticker shock: Price for Magnolia Bridge replacement skyrockets - May be cheaper to rehab

02/08/05

The dynamics of replacing the Magnolia Bridge have changed with a new cost estimate that makes the earlier 2002 figure of $100 million to $135 million look a bit like a bargain-basement price.

The new figure is plus or minus $200 million for all three alternatives, said Grace Crunican, director of the Seattle Department of Transportation. The jump in the cost estimate, in turn, has led the city agency to consider rehabilitating the bridge rather than replacing it with a new structure, she said.

The change in the price tag is based in part on geotechnical information that has come out in only the past couple of months. "We are looking at more uncertain conditions than what we thought we had before, so we have to worry about stability of the soil," Crunican said.

"It's a liquefaction issue ... and it's the depth of that," said project manager Kirk Jones of a process that destroys soil stability during an earthquake. Soil borings for all three alternatives showed that the problem goes much deeper than previously thought, he explained.

Other factors

Soil conditions aren't the only reason the price has gone up. SDOT has developed better estimates of the money needed to acquire the needed rights-of-way, along with a better idea of the costs for staging and detours, she said. "It's a tight, confined area no matter what you do."

Another reason the price is higher, Crunican said, is that she directed SDOT staff to come up with a cost estimate based on the mid-point of construction, a three-year project scheduled to begin at the earliest in spring 2009.

The more detailed information has led to a shift in thinking as well. "The other thing I've asked them to just assess right now is taking the bridge we have and retrofitting it," she said. "We're not calling it an active alternative right now, but I'd like them to scope it out."

Scoping out the idea will take a couple of months, said Crunican, who added that the retrofitting alternative could end up being included in the project's Draft Environment Impact Statement, which is due out next winter.

A rehab approach could end up being as or more expensive than the replacement alternatives, she conceded. "I just don't know what the situation is here."

Then again, rehabilitating the bridge could potentially be cheaper than replacing it, according to SDOT engineer Richard Miller.

"The first thing you do is work with the soils," he said. "The work that's been done so far is bracing, with no foundation work."

SDOT engineers would also have to decide if the existing deck could be kept, he added. "You might have to start with a totally new deck," Miller explained, "and then you'd need to look at what's between the deck and the soil, and that's all the column work." The question is whether the columns can be retrofitted, Miller said. "It might mean taking some of the bracing out, putting new bracing in."

If the bridge is retrofitted instead of replaced, it would still have to be brought up to current standards because of funding requirements, Jones said.

And a rehabilitated bridge would be expected to have the same useful life span as a brand-new bridge, Miller said. "It would take a lot of work," he conceded.

The traffic crunch

Jones estimated that retrofitting the bridge would put it out of action for at least two years, forcing roughly 20,000 car trips a day onto alternate routes on the Dravus and Emerson street bridges.

The time would be shorter if the bridge is replaced with another structure, because the existing bridge could stay in operation while a new one is built, he said. "The idea on all of these [existing alternatives] was to try to keep the existing bridge in operation as long as possible," Jones added.

In the worst-case scenario, the bridge would be out of commission for nine to 15 months, he said. It might not be that bad, though.

"When we sat down with some construction people this fall, they started looking at some ways they thought we could build some temporary structures ... that would substantially shorten that [time]," Jones said. SDOT won't do a detailed analysis of the possibilities for temporary structures until a preferred alternative is selected, he added.

The funding

The city is using $9 million in federal funding and $1 million in local dollars to pay for design work and the environmental impact study. It's an amount which will pay for approxi-mately 50 to 60 percent of that part of the project, Crunican said. "And so we'll be asking for additional money to finish the design work, and then we're looking for construction money," she said.

Money for construction costs will come from federal, state and local sources, but who pays for what piece of the funding pie still needs to be determined, according to Crunican.

"We don't know what the financing plan is going to be," she said. "We're trying to get through the environmental part and the design part...." The nickel gas tax is a possi-ble source of some funding, Crunican said. "But really, at a local level, we've lost money because of Eyman's initiatives."

Mayor Greg Nickels has lobbied the state legislature and the feds in the other Washington for funding, she said, stressing that replacing or perhaps rehabilitating the neighborhood bridge is a priority project in Seattle. "No one has forgotten the Magnolia Bridge, most of all not the mayor."

Staff reporter Russ Zabel can be reached at rzabel@nwlink.com or 461-1309.

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