Unsupported browser

For a better experience, please update your browser to its latest version.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

SR 99 update: Contractor tests TBM cutterhead

Seattle Tunnel Partners (STP) is preparing to resume tunnelling on the Alaskan Way Viaduct replacement project with testing of the stalled tunnel boring machine’s (TBM) cutterhead underway.

Last week, STP began rotating the cutterhead a few degrees at a time, stopping periodically to take measurements before completing a full rotation.

Yesterday, the crew marked the first sustained rotation of the cutterhead since the machine broke through the southern wall of the access pit on 19 February.

STP has indicated that it will now rotate the cutterhead in both directions for about one hour at a time. Watch a short video of the cutterhead rotating below:

During the next phase of work, STP will backfill the access pit with sand and gravel to prepare the TBM for tunnelling.

The machine is expected to resume tunnelling on 23 December.

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Links may be included in your comments but HTML is not permitted.