Feb. 26 project update: Bertha’s next move

Posted on Feb 26 2015 10:24 AM
After taking a break from mining to clean up the mixture of dirt, concrete and water that came into the access pit during last week’s breakthrough, Seattle Tunnel Partners has resumed Bertha’s final approach into the pit. 
Because the cutterhead has made it through the pit wall, there isn’t any digging left to do. The focus now is on building the concrete tunnel rings that enable the machine to move forward. Bertha must build five more rings – a process that’s explained visually in this animation (links to YouTube) – before she comes to rest near the northern edge of the pit. Bertha will continue to take breaks so crews can clean up debris.
When the machine reaches its destination, crews will begin disassembling the machine and preparing to lift pieces to the surface for repair. STP has said this process will take significant time and effort because it involves a number of steps. These steps include:
  • Installing work areas around the machine
  • Disconnecting joints, cables and hoses
  • Removing cutting tools and other parts from the cutterhead
  • Welding lift points on the body of the machine

When the disassembly process is complete, a massive red crane (links to YouTube) will move into position. Several pieces of the machine will be removed from the pit before the cutterhead, as illustrated in STP’s repair video (links to YouTube). 

We’ll continue to keep you posted as STP’s work moves forward. Remember to visit our access pit camera and follow Bertha on Twitter for the latest information.

Crews clean up debris in the access pit.
Repair plan resources:


Previous updates

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