Information from Seattle Department of Transportation

The Seattle Department of Transportation (SDOT) is continuing to make progress on repairs to the Spokane St Swing Bridge (Low Bridge), which has been stuck since December 23 when the mechanical and electrical systems were damaged during a severe ice storm. A more detailed version of this story with photos, videos, and diagrams is available on the SDOT Blog.

Crews worked hard over the weekend and successfully removed a damaged hydraulic turning cylinder inside the Spokane St Swing Bridge. This represents a significant step forward in the repair effort. Bridge engineers are continuing to work to reconfigure the eastern span of the bridge to run on one turning cylinder and continue testing to verify when the bridge can safely be reopened. 

The massive turning cylinder was removed over the weekend and transported to an off-site hydraulic repair facility to be overhauled. Removing the cylinder was a 12-hour process that involved hoisting the 15,000-pound cylinder onto an overhead rail system and carefully moving it outside the bridge pier housing. Our crews then used a forklift to move the cylinder onto the back of a truck to transport it to the repair facility. 

Bridge engineers have reprogrammed the computer system which controls the bridge equipment, and are now working to reconfigure the hydraulic system to function with one cylinder. Technicians are replacing the valves and hoses on the hydraulic power unit pumps which send fluid to the cylinders that open and close the bridge. During testing this week, engineers determined that several of these valves were broken and needed to be replaced to ensure the bridge operates safely and reliably. 

Once the hydraulic power unit pump valves and hoses have been replaced, bridge operators will continue testing the bridge systems to determine when it can safely be reopened to the public. People may see the bridge moving as we open and close the bridge for these tests. 

Once the bridge reopens, the eastern span of the bridge will operate on the one remaining turning cylinder while the broken cylinder is being refurbished. During this time, opening and closing the bridge for passing ships will take about 10-15 minutes longer than usual. 

Preparations to overhaul all four of the bridge’s hydraulic turning cylinders (two cylinders on each side of the bridge) began several months ago as part of this comprehensive repair and maintenance effort. When the unexpected damage to the cylinder occurred, the planning work that had already been completed allowed engineers to quickly jump into developing a response plan and will likely lead to repairs being completed sooner than if engineers had been starting from scratch. 

 Over the coming months, there will be additional bridge closures to reinstall the repaired cylinder and to complete other aspects of the Spokane St Swing Bridge Rehabilitation Program. SDOT already completed work to strengthen the bridge structure in October 2022 and is also planning to replace several other hydraulic components.

In response to the emergency bridge closure, SDOT worked to address the closure’s impact on freight movements and people who bike, walk, and roll. This included building temporary protected bike lane segments on West Marginal Way SW and First Ave S, adjusting traffic signals to keep freight moving, and working with Metro to activate the Transit GO Ticket app for free trips on the Water Taxi or bus rides.  When the bridge reopens, these temporary programs will end and SDOT will begin work to return the detour routes to normal.