Viaduct retrofit not cost-effective

SEATTLE – Retrofitting the Alaskan Way Viaduct would save little more than replacing it with a new elevated roadway, according to a state study.

The state-funded report by engineering consulting firm T.Y. Lin International suggests it is possible to retrofit the 53-year-old viaduct, but it would require extensive strengthening of the underground foundations.

It would cost $2.3 billion to retrofit the roadway that carries State Route 99 along the city’s waterfront. A new elevated road would cost an estimated $2.8 billion, and a tunnel – preferred by Mayor Greg Nickels and the Seattle City Council – would cost about $4.6 billion.

The Washington State Department of Transportation requested the latest study in response to retired structural engineer Victor Gray, who has said the viaduct could be repaired for $800 million.

He criticized the latest figures, saying an outside consultant should be calculating the retrofit costs.

“They can make those numbers say anything they want,” Gray said. “We need someone with an objective point of view. We need an independent, unbiased look at this thing.”

The Transportation Department has said it isn’t interested in a retrofit for the viaduct, which was damaged in the 2001 Nisqually earthquake.

“Major roadways in Washington are designed to a higher standard that ensures public safety in the event of a very bad earthquake. Gray’s retrofit proposal doesn’t meet that standard,” said Ron Paananen, viaduct project manager.

Paananen said the T.Y. Lin plan would only have a 25-year life span and would cost 80 percent of the elevated structure alternative.

“We also would be left with a structure that has no shoulders and narrow lanes,” he said.

The American Society of Civil Engineers, which also reviewed that T.Y. Lin report, found that Gray’s retrofit proposal is not a good option for the viaduct.

“With all of the factors in mind, the committee concluded that the relatively narrow difference in cost between the choice of a retrofit or rebuild weighs heavily in favor of rebuilding,” the engineering group wrote.

Gov. Chris Gregoire is scheduled to decide by the end of the year how the viaduct should be replaced.