Alert 6/7-8: Spokane Street Swing Bridge to West Seattle will close for repairs

SDOT will close the Spokane Street Swing Bridge (the lower West Seattle Bridge) June 7 and 8 to reinstall one of the key components in the mechanism that allows the span to open and close. There is no simple detour for a the swing bridge and its vital biking and walking trail. Instead, SDOT is advising folks to take the water taxi or the bus if they don't want to detour all the way to the 1st Ave Bridge. Though the Duwamish Trail provides a quality connection on the west side of the river, there is no all-ages-and-abilities bike connection on the east side. Refer to this excellent Bob Svercl video for guidance on how to bike across the river when the swing bridge is out. The city is not planning a temporary bike lane like the glorious 1st Ave S bike lanes installed during an extended emergency closure back in January 2023.

Crews are reinstalling one of the orange ones. Diagram from SDOT.

The work will reinstall one of the turn cylinders SDOT removed from the west pier during a previous closure and has since refurbished with some custom design changes they hope will avoid the kind of damage that led to the December 2022 emergency closure. The bridge has two piers, both of with much turn their spans in order to open the bridge for maritime traffic. Each pier can operate with only one turn cylinder each, but that leaves the bridge with little redundancy in case of another failure. Having two functional turn cylinders in each pier should improve reliability so long as repairs made in recent years to the large central lift cylinders and hydraulic systems hold. There sure are a lot of potential points of failure in this bridge design. Perhaps that's why nobody has copied this design in the 35 years since it opened.

The upcoming work is part of the city's ongoing project to keep the bridge functional, a need that became especially clear during the extended closure of the upper bridge starting in 2020. In addition to rehabbing some of the turning mechanism, the city has also removed important wiring from the upper bridge and installed it under the Duwamish River instead, further decoupling the low bridge's operations from its also unreliable and larger cousin. Work on the project will continue through 2025.

More details from SDOT:

From June 7 through June 8, crews will reinstall the refurbished cylinder we removed from the west pier during the October 2024 low bridge closure. This operation will require the closure of the low bridge for people driving, biking, and walking for about two days. We appreciate your patience as we complete this critical work.

Over the last several years we have also:

• Strengthened the bridge by injecting epoxy resin into existing cracks and adding carbon-fiber wrapping in several locations on both interior and exterior surfaces (completed 2022)
• Made earthquake safety upgrades (completed 2024)
• Upgraded the bridge control and communication systems (completed 2024)

These improvements are possible with local funds, including the 2015 Levy to Move Seattle. Additional phases of this project are expected to continue through 2025. Short-term closures will be required as part of our ongoing preventative maintenance work on this bridge.

Bob Svercl's video guide to detouring around a swing bridge closure: