Repairing Viaduct would cost $2.3 billion, state says

Retrofitting, rather than replacing, the Alaskan Way Viaduct will cost $2.3 billion, according to a study by the Washington State Department of Transportation.

The numbers, released today, support a memo that viaduct project manager Ron Paananen sent to the city of Seattle and others on Friday. It was in response to a state-funded report by T.Y. Lin International that suggested it was possible to retrofit the aging viaduct, but it would require extensive strengthening of the underground foundations.

The state Department of Transportation has long said it wasn't interested in retrofitting the viaduct, but commissioned the study in response to assertions by retired structural engineer Victor Gray that a retrofit made economic sense.

Gray has said the viaduct could be repaired for $800 million.

"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," wrote Paananen. "While T.Y. Lin has developed a plan that will, it doesn't pencil out. It 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."

The cost of a new elevated structure is estimated at $2.8 billion.

The new numbers, released today, say the cost of a retrofit would be almost as much as a new elevated structure. It said T.Y. Lin has developed a plan that could retrofit the viaduct, but the costs are prohibitive.

"For an earthquake of serious severity likely to have a one in 10 chance of occurring in the next 50 years, the standard would require that the viaduct, though it might be damaged, would still be usable after repairs," said the new state report. "T.Y. Lin's report outlines what would be necessary to meet this standard, including new bracing and other improvements, and also strengthening the footings and piers located in the weak and earthquake vulnerable soil on which the viaduct rests."