March 3 project update: Disassembly begins

Posted on Mar 4 2015 9:01 AM
Bertha reached her stopping point in the SR 99 tunnel access pit on Tuesday night, clearing the way for Seattle Tunnel Partners to begin a disassembly process that will likely take weeks.
 
Bertha moved forward a total of 57 feet between Feb. 17, when mining resumed, and yesterday. Along the way she built nine permanent concrete tunnel rings, which aren’t visible in the pit because they’re obscured by the ground and the machine’s exterior.
 
This time-lapse video (links to YouTube) documents Bertha's move into the pit.
 
With Bertha now in position, crews have begun the challenging task of taking apart the world’s largest tunneling machine. They will move through a number of methodical steps as they prepare to lift four pieces weighing up to 2,000 tons to the surface for repairs. Among other things, they must disconnect hundreds of hoses and cables, remove motors and weld lift points to the machine’s exterior.
 
When disassembly is complete, a massive red crane (links to YouTube) will move into position above the pit. Several pieces of the machine will be removed before the cutterhead is lifted out of the pit, as illustrated in STP’s repair video (links to YouTube). 
 
 
This Wednesday morning photo of Bertha in the pit was taken by our time-lapse camera.
 
Repair plan resources:

 

Previous updates

Feb. 26, 2015 afternoon update - Bertha's next move

Feb. 20, 2015 afternoon update - Tidying up the launch pit

Feb. 19, 2015 morning update - Bertha reaches daylight

Feb. 19, 2015 morning update - Bertha approaching the pit

Feb. 18, 2015 afternoon update - Bertha digs on

Feb. 18, 2015 project update - Bertha on the move

Archive of previous updates