CHOKEPOINTS

How Seattle plans to demolish the Alaskan Way Viaduct

Dec 5, 2018, 5:42 AM | Updated: Dec 14, 2018, 3:13 pm

What happens to the Alaskan Way Viaduct once the new SR 99 tunnel opens in 2019? After Jan. 11, the process of dismantling the viaduct begins.

RELATED: Seattle getting closer to Alaskan Way Viaduct closure

WSDOT laid out the process in a recent video on its website Tuesday, taking the public through step-by-step on what the demolition and dismantling process will look like.

In all, the demolition will take around six months, starting at the Columbia Street on-ramp, and extending north of Pike Street. From there, the demolition will extend out from Columbia north and southward.

Kiewet Infrastructure West will be overseeing the demolition, cordoning off two to three blocks at a time, and spending roughly 30 days on each section. The viaduct will be dismantled level-by-level from top to bottom.

Viaduct

The real difficulty of the project comes with how close the viaduct is from buildings and other elements of the city.

“What makes this unique is the close proximity of the buildings, [and] the massive grid of utilities that we’re going to be protecting,” said Dan Hemenway, Kiewet’s project manager overseeing demolition.

Girders close to those buildings will be removed via crane, and in some cases, barriers will added to protect them from rock, debris, and dust. Additionally, sensors will be implemented to ensure that noise and vibration are “kept within limit.”

WSDOT expects the the waterfront, Pike Place Market, Pioneer Square, and access to the ferry terminal to all be open and available during the demolition.

“Our goal is to have as little impact as possible,” Hemenway said.

The SR 99 tunnel will officially open in early 2019. Before that happens, there will be a three-week closure of SR 99 through downtown Seattle to realign the highway. Both the viaduct and the tunnel will be closed during this period. Additional ramp closures could mean up to six weeks of traffic disruption.

Chokepoints

I-405...

Chris Sullivan

Full I-405 closure coming this weekend

This is not the weekend to hit the Eastside because Interstate 405 (I-405), south of Bellevue, will be closed the entire time.

1 day ago

Image: SR 99 north in Seattle was closed due to a massive fire on Tuesday, July 9, 2024....

Steve Coogan

SR 99 north in Seattle reopens after major brush fire closed it for hours

All lanes on State Route 99 north end at the 1st Ave Bridge in Seattle were blocked Tuesday due to a fire. It reopened Wednesday morning.

3 days ago

sr 11 buckles heat...

Frank Sumrall

Stretch of SR 11 Highway buckles under extreme heat

WSDOT had to shut down State Route 11 to just one lane after concrete panels under the asphalt had buckled due to the region's recent extreme heat.

3 days ago

Image: The Good To Go Flex Pass sticks to a car windshield with small Velcro tabs and can be switch...

Chris Sullivan

‘Convincing’ Good To Go! toll scam rears its ugly head

Scammers are at it again, trying to get your personal information with bogus scam text messages posing as Good To Go! toll reminders.

4 days ago

Photo: Washington State Patrol troopers responded to a semitruck crash on I-5 north just before Sou...

Julia Dallas

Weekend I-5 delays: Semitruck driver suffers serious injuries after crash

Washington State Patrol troopers responded to a semitruck crash on I-5 north just before Southcenter on Sunday.

5 days ago

first avenue bridge...

Frank Sumrall

Southbound SR 99 closed over First Avenue Bridge for several hours

The First Avenue bridge on State Route 99 (SR 99) has been closed for multiple hours Saturday due to police activity.

6 days ago

How Seattle plans to demolish the Alaskan Way Viaduct