WEST SEATTLE BRIDGE: Deck-scan plans

(WSB photo, taken atop the bridge last week)

Next week, SDOT plans a “deck scan” of the Spokane Street Viaduct – that’s the section of the West Seattle Bridge that’s still open, east of 99. The announcement explains, “A deck scan is one way we understand the condition and performance of our streets and bridges to keep them safe and durable. … Our contractor will be conducting the deck scan to identify any potential defects with the following tools: A sound scan that uses sophisticated audio equipment to listen to the road with an array of microphones. The scan notes changes in acoustic response as it drives over the roadway, which helps us identify spots on the concrete deck that may result into future potholes. … Ground penetrating radar (that) uses electromagnetic waves to locate potential concrete delamination – or a layer of unbonded concrete – on the deck. Finally, we’ll use an overhead 4K camera to complete infrared imaging to take an in-depth view of the surface of the roadway.” This work won’t close the SSV but will lead to slowdowns, 7 am-5 pm Monday (August 30th) through Friday (September 3rd) next week. SDOT says a deck scan also is planned for “closed portions of the West Seattle Bridge and streets and ramps leading to it.” The north half of the Spokane Street Viaduct is less than a decade old, completed in 2012.

Mj August 25, 2021 (5:14 pm)

Wow SDoT actually conducting a project at good time!

Roms August 25, 2021 (7:15 pm)

Nah, that’s just SDOT trying to find ways to extend the viaduct closure ;-)

cjboffoli August 25, 2021 (5:29 pm)

Maybe while they’re at it they can seek to understand the condition and performance of the malfunctioning drains on this section of elevated roadway, which easily clog in even the most modest rains, creating large pools of standing water that increase the danger of hydroplaning, and that presumably contribute to the repeated erosion of the roadbed.

bill August 25, 2021 (8:30 pm)

Maybe the design work was hired out to engineers in Arizona who did not understand the memos about rain.
Chemist August 26, 2021 (12:42 pm)

I agree on the drains. I’ve been surprised at how little attention they’d get from SDOT, including the ramp to 99 nb during the regular inspection closures that would seem like an ideal time for cleaning.

namercury August 25, 2021 (5:53 pm)

This is where SDOT suddenly finds the re-opening is delayed until December 2023. Yes! I’m a little cynical and skeptical! :-)

Mj August 25, 2021 (7:22 pm)

I’m curious as why SDoT has not yet painted double white lines with signage illegal to cross double white lines approaching the 5-way intersection from the south with some channelization arrows yet? Like what was done EB Spokane viaduct to NB SR – 5 a few years back to discourage merging at the last minute.

helpermonkey August 26, 2021 (8:06 am)

the entrance to the West Seattle bridge had been falling apart for years, giant crumbling potholes as you go around the corner by Nucor. It seems like over the last year and a half they could have at least been working on that roadway. Once they reopen the repaired bridge it will be too late. Come on, SDOT, get your shizz together on this.

Derek August 26, 2021 (9:06 am)

When does real bridge work start? Like the actual repairs?

WSB August 26, 2021 (9:32 am)

November is the most-recent estimate, with an updated timeline estimate due next month as design nears completion. SDOT will have bridge-program reps at tonight’s West Seattle Transportation Coalition meeting if you want to ask them directly.