Cooling down hot moving bridges

Dawn breaking on the Ballard Bridge | Photo by David Johnson


What do you do when the city experiences three consecutive days of 85+-degree weather?

A. Drink a lot of water

B. Cool off your britches with a pool dunk

C. Cool off moving bridges with a water flush

D. All of the above


Admittedly, any of these answers is right – though our Roadway Structures bridge crews focus on “C”. That’s because temperature changes cause steel and concrete to expand and contract, a potential problem for bridges that open and close for passage of marine vessels. Too much expansion can create pinch points, where bridge sections can rub – and therein lies the rub, and reason for the flushing.


With this week’s high temps, the cooling truck (like a calming goat, only different) was out Thursday, at all three Ship Canal bridges – University, Ballard, and Fremont – consecutively. The water flushing operations are scheduled when Seattle experiences 2 – 3 consecutive days of at least 85-degree heat. Lucky for us, it didn’t get as hot as THIS looks…

2011 Google Earth Visual | Discover Magazine |


Thanks to everyone for your patience during those 5-10-minute bridge closures! If temps creep up again, expect to see moving bridge gates down, just briefly, for that cooling/flushing truck and our team to work some misty magic!

SDOT Roadway Structures crews using the bridge cooling truck.



W Seattle Lower Bridge is Operational!

Luck Favors the Prepared

Snapshot from live traffic cameras | 06.26.18

In case you haven’t heard, the Lower Spokane St Bridge (a.k.a. West Seattle lower bridge) is open to all pedestrian, bicycle and vehicle traffic! The swing bridge went into its ‘open for marine vessels’ position last Wednesday at 8 PM, with an expected week or more to get it back online.  The key to pulling it together? A spare!


Love the Spare

The SDOT Roadway Structures team thinks about future needs, and had a spare piston assembly stored in case the swing bridge ever lost its swing. Like a spare tire, the spare hydraulic cylinder got people up and traveling again, much sooner than it might otherwise take to fix a leaking piston assembly.

The spare assembly is a lot to love, about 15 tons, and took a special heavy duty forklift to move it. Thanks to United Motor Freight, Inc, located right next to the bridge, and President Jeff Landstrom, for making the emergency response vehicle available!.


PM Commute Joy

Around lunchtime today, Roadways Structures crews completed several test openings, with the installed spare, then picked up all the traffic control and detour signage…to swing back into business! That means the bike shuttle put in place during bridge repairs, provided its unceremonious last operation during this morning’s commute.


Many Thanks!

Thank you to everyone for your patience and understanding—and crews for your 12-hour shifts! More details to come on the originally identified problem, when the damaged piston assembly is inspected later this week. Work this last week focused singularly on efficient opening of the Spokane St Bridge, as a priority for travelers.


For more on what’s impacting traffic, visit…

What’s Moving Seattle This Week?

Update 5: W Seattle Lower Bridge

Weighty Subject

Today, the Roadway Structures crew is moving a 15-ton replacement cylinder into its exact place, inside the west shore pier house of the W Seattle Lower Bridge.

The bridge was swung out to its marine vessel position last Wednesday, to further investigate a hydraulic fluid leak.

Roadway Structures crew maneuvers 15-ton cylinder | June 25, 2018

Roadway Structures crew maneuvers 15-ton cylinder | June 25, 2018




Photo by Casey Allen | Pexels

Maneuvering replacement parts the combined weight of two elephants is no simple task. The nearly 30,000-pound cylinder must be installed per specific controls, right down to cleaning it, along with reconnecting hydraulic oil lines, rewiring electrical conduit, etc.

Huge piston assembly cylinder must be clean for install.


There’s also continuous monitoring and testing along the way (not of the elephants; rather, operation of the 15-ton replacement cylinder). It all means there are several more days of hard work ahead.


4 x 12 Effort

On Saturday, the team worked a 4th consecutive 12-hour day, pulling the huge, damaged piston assembly out of its tightly placed spot, and delivering the new one to just inside the pier house dome. With such long hours and critical work, the team rested Sunday to ensure both a safe and successful effort kicking off again this morning.


The damaged piston assembly cylinder will be inspected in detail locally, to determine to cause of its hydraulic fluid leak.


What You Can Expect

The Spokane St Swing Bridge, a.k.a. W Seattle Low-Level Bridge over the Duwamish River, remains out of commission, potentially through the end of the week. We expect to know more tomorrow, June 26, 2018.


 Detour routes are marked at the following locations:

  • Chelan Ave SW
  • 1st Ave S
  • E Marginal
  • Harbor

Visit our What’s moving Seattle this week? blog for navigation tips.



 Shuttle service for bike commuters is running during the week, 6 – 10 AM and 3 – 7 PM, carrying up to 15 passengers each trip.

 Shuttle pick-up & drop-off is at bridge approaches; arriving at each side every ~20 minutes.

For biking around the Duwamish River to the next cross point, see our Bike Detour Map and suggestions in Update 4


Here’s to a successful West Seattle Lower Bridge Repair this week, coming back strong and swinging!

SW Spokane Street Swing Bridge to Close to Marine Traffic December 8

SDOT advises travelers that the SW Spokane St Swing Bridge will be closed to marine traffic on Thursday, December 8, for approximately four hours from 8 a.m. to 12 p.m. for maintenance.

The date and time was picked to minimize the impact to marine traffic. Vehicle traffic across the bridge will not be impacted by this work.

Questions or concerns about the closure can be directed to Paul Elliott, SDOT Community Relations, (206) 684-5321 or

Update: Northbound Lane Restriction on Ballard Bridge Scheduled for November 22-23

SDOT is advising travelers that the northbound right lane of the Ballard Bridge will be closed for maintenance on Tuesday, November 22, and also on Wednesday, November 23, from 8:30 a.m. to 3 p.m.

The work will not affect the east side northbound pedestrian path or marine traffic.

SDOT thanks the public for its patience while this work is being completed.