Seattle mayor chooses repair option to reopen city’s busiest bridge

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Updated May 20, 2021
The West Seattle Bridge has been closed since March 23 due to rapidly growing cracks underneath its deck. Credit: Seattle DOTThe West Seattle Bridge has been closed since March 23 due to rapidly growing cracks underneath its deck. Credit: Seattle DOT

Seattle’s busiest bridge, which has been closed since March 23, is now slated for repairs that are expected to open the bridge by mid-2022, according to Mayor Jenny Durkan’s office.

Durkan was faced with a choice of repairing or replacing the West Seattle High-Rise Bridge. The repair is estimated to cost $47 million, while replacement would cost $383 million to $565 million with an estimated completion of 2026.

In choosing the repair option, Durkan cited the faster timeframe and lower cost.

“This corridor is critical to our economy and our residents and the other options could not realistically be done in a reasonable timeframe, would cost significantly more money and provided no more capacity for transit or other modalities,” Durkan said. â€śWhile all options have risks, repair will get West Seattle reconnected the fastest and funding is more certain.”

The repair option, however, is a temporary fix, anywhere from 15 to 40 years. A Seattle Department of Transportation cost-benefit analysis of the bridge choices said it was not confident how long the repair would last. It also noted that replacement would still be required and would lead to eventually closing the bridge. Annual maintenance would also be required, and additional funding would be needed.

Consulting firm HNTB has been hired to move forward on plans for the future replacement with a new bridge size, type and location study, according to the mayor’s office.

Credit: Seattle DOTCredit: Seattle DOT

So far, the city has spent about $20 million to stabilize the bridge and make emergency repairs since cracks were found to be growing significantly. The cracks were discovered in 2013 on girders under the concrete deck but began to grow more pronounced in the past year. The mayor ordered the bridge closed March 23.

Since its closure, SDOT has released damaged bridge bearings at the Pier 18 column and installed new post-tension steel cables inside the bridge girders for additional support to the main arch, the mayor’s office reports. The recently approved repairs will continue that work to stabilize the structure.

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The 46-year-old bridge is between Interstate 5 and Fauntleroy Way SW and crosses Harbor Island. A lower two-lane bridge is open only to emergency vehicles, city buses and freight traffic, while general motorists must take a detour. Combined, both bridges handled about 100,000 vehicles a day.

For a look at the bridge’s damage and new post-tension cables installed, watch the SDOT video at the top of this article.