Available Resources

Video: Inside tunneling under the Alaskan Way Viaduct

From WSDOT’s video description: After nearly a week of tunneling under the Alaskan Way Viaduct, crews are steadily continuing Bertha’s underground drive towards downtown Seattle. This video gives you a behind-the-scenes glimpse into how the […]


Bertha's scheduled maintenance stop
Project Related

Bertha Demo Period Done, Resumes Mining

The Bertha tunnel boring machine has resumed chewing away beneath Seattle after a ‘suspension for cause’ order from WSDOT shut it down in January following two safety incidents. The BTM began tunneling with some conditions […]


Malcolm Drilling's clamshell bucket taking a scoop out while excavating the access pit
Project Related

Update on Access Pit for Repairing Bertha TBM

There hasn’t been much to report recently for the Alaskan Way Viaduct Tunnel Project in Seattle. As you probably know, Bertha has not advanced since about December of 2013 after drilling through an abandoned steel […]

Project Related

Feb. 7 Bertha update: Two factors contributed to tunnel stoppage

WSDOT released an update on February 7 with some conclusions regarding the blockage that has stopped the Alaska Way Viaduct Tunnel Boring Machine, Bertha’s progress since December 6. Now they don’t think it was necessarily the well casing after all.

They cite two factors that contributed to the blockage. First, the cutterhead was clogged with material. You can see an cool short video of a worker unclogging the cutterhead. Not terribly dramatic, but still cool. The second factor was increased temperatures inside the equipment. STP discovered damage to a seal that protects the machine’s main bearing. They are still determining how the repairs will be done.

If you want to follow the chronology of this issue, read below for summaries and links to previous updates from WSDOT. And Check out the videos too! [Source: WSDOT]

[…]


Malcolm drilling crews setting up to drill secant pile shafts for TBM launch pit
Project Related

Digging deep to drill Highway 99 tunnel

Construction has started on the tunnel boring machine launch pit for the WSDOT SR 99 Tunnel Project (Viaduct Replacement). The 420 foot long pit is being constructed using secant pile retaining walls, with 2 rows […]