The West Seattle Bridge has been closed to all traffic since March due to cracks in the concrete girders. (Mike Siegel / The Seattle Times)
The West Seattle Bridge has been closed to all traffic since March due to cracks in the concrete girders. (Mike Siegel / The Seattle Times)

Seattle’s bridge-maintenance spending, which averages $6.6 million per year, is inadequate and a reason why “the condition of the city’s bridges has worsened over the last ten years,” a new audit report released Monday says.

The city’s own transportation managers told auditors that bridge investment should be five times as high.

But the report also says that the Seattle Department of Transportation (SDOT) deploys its own bridge maintainers to other divisions and departments 20% of the time, to do “reimbursable work” that helps to shore up the SDOT budget. Auditors believe the side jobs impair SDOT’s ability to tackle complex, multiday bridge fixes.

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Alex Pedersen, who heads the City Council’s Transportation and Utilities Committee, says he hopes colleagues keep the audit in mind when Mayor Jenny Durkan releases her 2021 budget proposal in two weeks.

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“They need to look at the entire budget and get back to the basics. That includes bridges. The West Seattle Bridge is a wake-up call,” said Pedersen, who requested the audit. “I think we need to move the needle in the right direction. We should be adding funds.”

SDOT closed the concrete span March 23 because several shear cracks — discovered in 2013 — suddenly accelerated to create a potential risk of collapse. Repairs to stabilize the bridge are underway, and it may be able to reopen by 2022.

Besides the cracked West Seattle bridge, the city operates a trio of century-old drawbridges over the Lake Washington Ship Canal.

Roadway structures director Matt Donahue told The Seattle Times two years ago that the city needs to increase spending on bridge maintenance. Monday’s audit cites a “conservative” SDOT estimate that $34 million a year should be spent just to maintain older bridges.

An SDOT blog post Monday said the agency concurs with most recommendations in the audit, which “reinforces ideas for improving our already strong bridge maintenance program to support our aging infrastructure.”

Property tax funds are being spent this year to rebuild a rotted Fairview Avenue timber-piled bridge near South Lake Union. The city will soon open the Lander Street Overpass above train tracks in Sodo.

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In calling for “back to basics,” Pedersen brought up the Central City Connector streetcar, whose estimated costs have reached $210 million, as a place SDOT could trim spending and apply dollars to bridge work. Supporters pointed to the prospective 20,000 daily riders, in boom times, as a reason for the streetcar line on First Avenue.

The five audit writers considered data on 77 bridges, listings in the National Bridge Inventory and interviews with SDOT and Federal Highway Administration officials.

Only 29% of Seattle bridges are considered in good condition, a rate comparable to Chicago or Minneapolis, compared with 38% in 2010, the audit says.

The University Bridge, which carries 36,000 vehicles daily, is considered poor while the West Seattle Bridge, which carried 108,000 daily vehicles before the coronavirus pandemic, was rated fair before the crack emergency.

According to a City of Seattle SDOT report, the University Bridge, pictured here Monday, September 14, 2020, condition was rated poor. The bridge carries 36,000 vehicles daily according to an SDOT report. (Greg Gilbert / The Seattle Times)
According to a City of Seattle SDOT report, the University Bridge, pictured here Monday, September 14, 2020, condition was rated poor. The bridge carries 36,000 vehicles daily according to an SDOT report. (Greg Gilbert / The Seattle Times)

SDOT pledged to establish a more sophisticated asset-management program.

Director Sam Zimbabwe, in his formal response letter, also said the West Seattle Bridge closure does not “appear to be the result of any deficiency in our bridge maintenance program,” because inspections there were increased during recent years.

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He defended the reimbursed non-bridge jobs, saying those can be managed “in a way that prioritizes bridges first.”

Zimbabwe also noted that bridges are only part of SDOT’s $20 billion in assets that need maintenance and money, a hint that obtaining some torrent of bridge cash will be easier said than done.

Pedersen said while he can’t be certain tight budgets played a role in the West Seattle crisis, there’s a definite relationship between money and bridge preservation.