VIDEO: Here’s what the West Seattle Bridge pre-reopening ‘load testing’ looks like

1:52 PM: As we first reported last week, today’s the day that SDOT planned to begin one of the last critical tasks before reopening the West Seattle Bridge on Sunday (September 18th) – load testing. It involves trucks moving across the bridge with “specialized heavy loads,” and SDOT has recorded some of it via drone video we just received.

While this needs to be done before the bridge reopens, SDOT has said repeatedly that the repaired bridge already has been tested in other ways and has performed as expected, so they’re not anticipating any surprises. Still no word of exactly what time Sunday they plan to start pulling down the barricades to end the 2 1/2-year closure.

3:31 PM: So what happens now? SDOT spokesperson Ethan Bergerson says, “It will take us a few days to analyze the data.” Likely that’ll be complete by Friday afternoon, when a pre-reopening media briefing is planned.

Boinsted September 13, 2022 (3:05 pm)

What does success look like here? If none of the dump trucks fall through the bridge deck then we open?

WSB September 13, 2022 (3:30 pm)

Adding one line – they’ll analyze the data over the next few days.

Diane Fields September 13, 2022 (3:21 pm)

As long as it can hold my little Nissan. I am good. Holy cow, so close.

AMY September 13, 2022 (3:36 pm)

I’m not sure I remember how to get to the bridge on ramps!

Days to analyze?!? September 13, 2022 (4:15 pm)

They’ve been touting their state-of-the-art sensor array and monitoring… unless some alarms were going off, the bridge should be open. Now. Cut the crap and get out of the way. And if there were alarms going off, well then we should secede from Seattle. That would then make this either a county or state roadway and get a new agency running the show. Everyone associated with this project should be unemployed and probably unemployable.

ColumbiaChris September 13, 2022 (4:41 pm)

Good thing you’re not the one who’s in charge of everyone else’s safety.
Jethro Marx September 13, 2022 (4:49 pm)

I hope after the bridge opens, we can continue to count on the comment section to out-engineer the people who are trained and paid to make sure your car doesn’t fall through the bridge. That includes dump truck teams, technicians of all sorts, and analysts.
- MyThruppence September 13, 2022 (5:00 pm)
  
  Did someone call for an armchair analyst? Let me just begin by saying that everything that everyone is doing is wrong…
Reed September 13, 2022 (5:45 pm)

I have a crisp $100 bill betting Days to analyze causes the accident that will close the bridge on the first day of opening.
- Ketie September 14, 2022 (8:18 am)
  
  Oh please don’t jinx it, I have been waiting so long for that damned bridge to open again, that would be so upsetting if it closes right away
- WS Res September 14, 2022 (9:19 am)
  
  I’ll totally take your bet.

S September 13, 2022 (4:34 pm)

Anyone putting money on the bridge opening before school starts?

North Delridge September 13, 2022 (5:10 pm)

Is there a spread anywhere?
WestSeattleBadTakes September 13, 2022 (5:33 pm)

Wow, you lost that within an hour.

Doug Greenswag September 13, 2022 (5:18 pm)

I wonder why the load testing seems to have the trucks standing still. It seems to me that load testing would involve weighted loads in motion. I think that motion would send vibrations through the bridge structure. Such vibrations would perhaps better indicate how the crack repairs hold up in conditions closer to real world use of the bridge.

WSB September 13, 2022 (5:33 pm)

This isn’t the entirety of the testing – they sent some clips from the early going. And these are two of five clips they sent – another shows one truck in motion at ground level; I’ll add that a bit later.
- Douglas Greenswag September 14, 2022 (6:07 am)
  
  Watched the video of the single load testing truck in motion. In contrast, a typical day after the bridge reopens will involve hundreds of trucks, busses and cars headed in both directions, often at highway speeds. It would be nice to get an explanation of how the load testing gets analyzed/interpreted so that it is considered an appropriate proxy for the expected day-to-day regular use of the bridge. I am not saying that it can’t be done this way, only that I think we are entitled to an explanation of why the testing done is appropriate and adequate to the task. Kraemer North America ( the contractor ) is a good company with lots of experience in this field. They have a lot on the line in this project. They should be able to explain it in lay terms.
Neighborhood Engineer September 14, 2022 (7:59 am)

Vibration Engineer here: Like the other commenter said, they do both. With the trucks standing still they do what’s called a SLT, or static load test. This helps them determine live load distribution factor (basically how well the bridge distributions a fixed force) and load rating factor (how much force it can withstand essentially). They can also judge how serviceable the bridge would be by looking at deflection limits. Now comes my specialization haha; the modal characteristics (frequencies where the structure is most vulnerable due to physical design) are found by doing these moving tests (dynamic load testing). They do this with different weights and speed cases and should check it against their finite element model (super complex simulation)

Mj September 13, 2022 (5:22 pm)

S – I’ll wager everything that school starts before the bridge opens.

David September 13, 2022 (7:25 pm)

Oh bridget – My heart furloughs, begot in ancient Hello’s.

CAM September 13, 2022 (8:41 pm)

Thank you David. Less of all the rest, more of this. 5 more days.

Odd son September 13, 2022 (8:13 pm)

The curve on the bridge near Fauntleroy is almost notorious for accidents. If you haven’t driven on the bridge, please be careful. If you have driven on the bridge, this is just a gentle reminder. I want everyone to be safe but it’s also a major traffic jam when people hit the wall and or spin out at the curve. Thanks.

WSB September 13, 2022 (8:18 pm)

As reported previously, they’ve put a special anti-slick coating and grooving on that curve, so things just might be better.
- RCS September 14, 2022 (11:30 am)
  
  Oh wow I hadn’t heard about this. Thanks for the scoop and ongoing reporting!