WEST SEATTLE BRIDGE: Another stabilization milestone – Pier 18 bearing release

12:01 PM: SDOT says its stabilization contractor Kraemer North America has reached another milestone. SDOT spokesperson Ethan Bergerson tells WSB, “We have completed the Pier 18 release work as planned.” SDOT detailed the Pier 18 bearing problem in April: “We discovered that one particular joint has become stuck, which appears to be magnifying the daily stresses on the bridge. Specifically, the issue is with the lateral bearings at the top of the Pier 18 support columns. This isn’t the sole cause of cracking on the bridge, but our bridge experts think it is a major part of the problem.” The bearings are pieces of rubber that “manage movement” as the bridge handles traffic and other stresses. The release is just part of the stabilization work – other parts involve strengthening the damaged section of the bridge – but it’s definitely a milestone. SDOT promises more details later today on what the Pier 18 release means and what’s next. We’ll add that information when it’s in.

2:12 PM: SDOT’s full announcement is now out, including:

… SDOT bridge engineers worked with the contractor to determine the best way to “release” the bearings so they are no longer compressed.

This involved building a temporary platform to perform the work. Then, specialized equipment was used to precision-demolish the concrete surrounding the bearings. Over the next couple of weeks, we will place the new bearings, and then pour the new concrete to hold them in place, setting the stage for future repair or replacement of the bridge.

The bearing release is part of a series of vital steps we’ve taken to stabilize the bridge since it closed in March. Within weeks of closing the West Seattle High-Rise Bridge, SDOT has had crews on top, underneath, and inside the bridge working six days a week to stabilize the center span, make it stronger and keep options open.

As the important discussion about repairing or replacing the bridge continues, crews are continuing to focus on measures that need to occur regardless of whether the bridge will be repaired now or if we will pivot immediately to replacement. This includes carbon fiber wrapping and installation of a post-tensioning system, both of which will wrap up later this month.

As colder temperatures and increased moisture can cause bridge elements to expand and contract, SDOT will continue to monitor the bridge with the intelligent monitoring system installed in May.

Flivver November 5, 2020 (12:22 pm)

Let’s hope sdot get’s their bearings and repairs and opens the bridge!

Brian November 5, 2020 (12:57 pm)

I recall from the reporting, that this Pier 18 bearing problem was first seen in 2013 or 2014. Why wasn’t this addressed back then? I’m not a civil engineer, but if you have an important component of a bridge that starts to malfunction, and could threaten the integrity of the bridge, why wouldn’t one resolve that malfunction sooner than later? Again I only used a plastic straw to model what has been described, but if you twist a plastic straw from both ends the middle of the straw collapses. The bearing at Pier 18 keeps the box girder supporting the bridge from “locking” and hence twisting, and cracking which is what we are now attempting to resolve. While it would have been painful back then, if the bridge had been closed for a month or two 6 or 7 years ago, we just maybe could have avoided this? I reiterate I’m no expert but someone or some part of the organization was unable to look at the information that was available and make the correct call.

Frog November 5, 2020 (2:02 pm)

The question has been asked many times before, and the answer seems to be: they found a consultant who said they didn’t need to. (Also, the dog ate their homework.) Look a little deeper, and it probably reflects SDOT priorities in recent times. All the passion there is for closing roads, shrinking roads, building obstacles in roads, and any other thing they can think of to make life harder for drivers of private cars, because global warming etc. Maintaining roads is expensive and boring.
BBILL November 5, 2020 (2:38 pm)

The report you reference (http://www.seattle.gov/Documents/Departments/SDOT/BridgeStairsProgram/West%20Seattle%20Bridge/Inspection%20Report%20-%207-5-13.pdf) has a lot of recommendations/observations in it, and in many cases the recommendation was “Continue To Observe (CTO).” Looking backward it’s “easy” to pick one thing out and say more should have been done for that one item. The problem is identifying which item needed extra attention beyond the recommendation looking forward at that time with the information known.
- Pete November 5, 2020 (3:40 pm)
  
  But the city and SDOT specifically have a history of not doing routine maintenance on our infrastructure. It is much easier to spend tax dollars on the shiny new object in the window than to take care of what you already have it seems.
  - BBILL November 5, 2020 (3:56 pm)
    
    For most items in the report above, the official recommendation was CTO. If I put you in the position of spending other people’s money (taxpayers’ money), how much more would you personally have spent [=raised taxes], and would you have been elected by the voters to tax them that much?
    - Canton November 5, 2020 (8:51 pm)
      
      Guessing Brian’s reply, is similar to a car’s oil leak. Do you observe the leak and CTO? Or do you remedy the problem before the engine seizes?
    - BBILL November 6, 2020 (1:04 am)
      
      Haven driven a vehicle with an oil leak for a few years, and I continued to observe. Oh, yeah, that’s right, I added oil as necessary.

Steve November 5, 2020 (1:59 pm)

Maybe this is good news if the bearing is fixed? It sounds like it was definitely a factor in the cracking. Now that the post-tensioning cables and carbon wrap are about finished along with filling the cracks maybe the bridge could reopen in the next few months? I imagine they need to look at weight…maybe an engineer can tell us which is worse….three lanes of moving traffic or two lanes of standing traffic? I imagine that four lanes eastbound are gone and were likely a big mistake that wasn’t adequately studied. Keep all the buses on the low bridge and eliminate the bus lane?

BBILL November 5, 2020 (2:43 pm)

“I imagine that four lanes eastbound are gone and were likely a big mistake that wasn’t adequately studied. ” Your imagination is not evidence as to whether the live load was properly assessed at the time that changes were made. If the basic claim is true, that the change in live load was inadequately considered, it would be nice if someone would present *some* evidence of such. Interestingly enough, I have personally observed that many of the commenters here on the WSB complain that too often the City/SDOT considers too many factors, thus taking too much time. For example, let’s say that SDOT recommends an engineering study before reopening the bridge that will take a year or two–how many would support that?

smittytheclown November 5, 2020 (2:56 pm)

Inching closer to repair!Woo Hoo!

Colonel Mustard's Wrench November 5, 2020 (3:56 pm)

Why is it that bearing suppliers in the industry know that bearings need to be maintenanced at the 30 year mark, but SDOT didn’t seem to know that ?

Can someone remind me why Sam Zimbabwe still works for the city ?

dsa November 5, 2020 (4:26 pm)

To quote SDOT from the link above “The bridge’s four main support piers hold up the three highest spans of
the bridge – the part that goes over the Duwamish River, between Harbor
Island and West Seattle. Pier 18 is the support structure on the east
side of the high-rise span, towards Downtown Seattle. “So if the stuck bearing really did have something to do with the cracking on the east side, *what caused the cracking on the west side*? Is the pier 16 bearing stuck too?

BBILL November 5, 2020 (8:36 pm)

In regards to your basic question as to where/why cracks are forming relative to the location of bearings, take a look at where the tendon anchors are, which is outlined in the bridge reports.

Busses and Emergency vehicles across the high bridge November 5, 2020 (5:43 pm)

When the carbon wrapping is done and high bridge is stabilized I hope they will allow emergency vehicles and busses across the high bridge. The “ intelligent monitoring system” the City installed in May can quickly tell of more load is creating more stress. Then they can increase access across the lower bridge for more (people, hours, types of vehicles) or all (people, hours, types of vehicles).

Alkilocal November 5, 2020 (8:54 pm)

This is great news. And since the buses and heavy trucks have gotten used to using the lower bridge, car traffic only can be maintained on the upper bridge to reduce weight induced wear to prolong the fix…right? But I’m sure SDOT is familiar with load, load assessment, live and active load issues with heavy weight trucks and buses and such like that.

David November 5, 2020 (10:27 pm)

Not to mention that when traffic gets jammed due to heavy trucks slowly entering and exiting, that for sure increases the weight load. But good luck getting city government to say no to big business… considering that they prioritized them for the lower bridge in the first place.

Rick November 6, 2020 (9:27 am)

BBILL- I’ve had a few of those cars. It was usually “fill it up with oil and check the gas”.

BBILL November 6, 2020 (12:32 pm)

If the bridge could have been saved with a couple quarts of oil every few weeks, I’m willing to bet SDOT would have done so.

Sorry, comment time is over.