State transportation officials broke their silence Friday on problems with "Bertha," Seattle's giant tunnel digging machine, and it’s not good news.
They told reporters that their contractor Seattle Tunnel Partners (STP) thought they found what has kept Bertha from digging for nearly two months. During an inspection in a pressurized chamber, they found several areas where the cutter head was clogged with earthen debris.
They cleaned up that problem and saw no obvious signs of obstacles in Bertha’s path, so they started up again.
Temperatures rose after the machine moved just a few feet so they shut it down and sent in inspectors. That’s when they found the protective seal around one of Bertha’s most important parts had been damaged. The main bearing seal was leaking allowing silt and water to get inside.
Managers said they will probably require a replacement of the seal and if there was damage to the main bearing itself, it may need to be replaced. That’s a worst case scenario, but at the very least, Bertha needs serious repairs and she won’t be moving until she gets them.
WSDOT officials said they have no idea when the digging will resume but it has to be fairly soon.
The partner project, the seawall replacement, is also underway with the understanding the tunnel project will be making progress. There are concerns a stuck Bertha could slow down that project as well.
On Friday, WSDOT posted multiple YouTube videos of crews inside the tunnel working to unclog the cutterhead.
The machine is only one-tenth of the way toward completing a 1.7-mile tunnel. The tunnel will carry Highway 99 traffic and allow the removal of the aging Alaskan Way Viaduct along the Seattle waterfront.
The total viaduct replacement is estimated to be a $3.1 billion project.
The Associated Press contributed to this report.