Remodeling Bertha’s launch pit

Seattle Tunnel Partners, our contractor for the SR 99 Tunnel Project, is remodeling the giant concrete box where they assembled, tested and launched Bertha, the world’s largest tunneling machine.  

Fittingly, Bertha’s launch pit is massive – 400 feet long and 80 feet wide. It was 80 feet deep, but it’s a little shallower now due to the remodel, which is turning the pit into part of the future State Route 99.

Remodeling the launch pit isn’t too much different than renovating an old home. Just like you might start a home remodel by removing furniture and other things in the way, crews first removed the metal frame and temporary tunnel rings that Bertha pushed off of at the start of the tunnel drive.

With those items out of the way, crews then started filling in the bottom of the launch pit and putting in a new floor, which will function as the future northbound lanes of SR 99 that traffic will use to enter the tunnel.

Another common remodeling task performed by crews: gutting part of a wall. In this case, though, it has nothing to do with creating a more open floor plan. Instead, this opening allows crews to start building permanent connections between the launch pit and the tunnel operations building under construction next door. Operations buildings at both ends of the tunnel will serve as hubs for operating and maintaining the tunnel’s lighting, ventilation, safety and traffic systems.

Later this summer, crews will start building the next floor up, which will include the new southbound SR 99 lanes that will carry traffic out of the tunnel.

All these changes may be hard to visualize. Fortunately, crews have built a similar section of the future State Route 99 just south of the launch pit.  If you click on the link, you’ll see a light at the end of a tunnel. That light is the launch pit.