Bertha not expected to move for months as tunnel workers attempt to fix machine
There will be no quick or easy fix for the broken tunneling machine under Seattle. The Washington State Department of Transportation now says it will be months before Bertha starts drilling again.
Seattle Tunnel Partners is working with Hitachi Zosen, the machine’s manufacturer, to determine how best to fix the broken seals surrounding the main bearing of the boring machine. They say it could be another six or seven months before the giant drill starts churning under Seattle.
The state is weighing several options on how to fix the broken seals that lubricate and protect the main bearing that powers the cutterhead. The Seattle Times reports the state might have to dig a pit 115 feet deep in front of the drill to remove the 630 ton cutter-head to replace the seals.
The contractor says the state could also take apart the drill from the rear and reach the seal that way. Depending on what inspections this week show, the contractor might be able to deliver the parts through the back of the machine.
Either way, it will be months before drilling resumes.
Engineers still don’t know why the seals on the $80 million machine failed.
The machine has been mostly idle for two months and is only one-tenth of the way toward completing a 1.7-mile tunnel.
The project is budgeted at $1.4 billion. The total viaduct replacement is estimated to be a $3.1 billion project. The tunnel project is supposed to be finished in late 2015.
The Associated Press contributed to this report.