SR 99 Tunnel
Tue March 11, 2014
Bertha's Very Bad Week, A Timeline
It’s been hard to get straight answers about what forced Bertha, the world's largest tunnel machine, to halt. It began boring July 30, 2013, and when Bertha broke down in December, it was ahead of schedule. Since then, the machine has been mostly idle beneath the Seattle waterfront. Project officials still haven't publicly identified a root cause.
We obtained internal Washington State Department of Transportation documents under the state’s public records act to try to piece together what went on beneath the surface when Seattle's $3.1 billion megaproject went off the rails.
Tuesday, December 3: Record Day
Already ahead of schedule, Bertha has its best day ever – moving forward 59 feet. A WSDOT inspector mentions noticing “lots of grease present” near the machine’s main bearing in a report.
Wednesday, December 4: Stops And Starts
Early Wednesday morning, drilling stops three separate times to remove unusual objects from Bertha's conveyor belt: a piece of steel pipe, then a large boulder or chunk of concrete, then more steel pipe. The drilling resumes, and Bertha keeps moving forward.
Thursday, December 5: Heating Up
Workers on the graveyard shift try to drain off the groundwater in front of Bertha. They want to see if something is blocking the machine. They fail – water keeps filling up the space in front of Bertha but drilling resumes.
By the afternoon, Bertha is stuck. The crew spends three hours trying to get the machine to move forward. Each time they do, the seals around Bertha's main bearing quickly heat up, and they have to shut it down and wait for it to cool off.
They even allow Bertha to heat up a little more than usual, up to nearly 150 degrees Fahrenheit, but it doesn't help. Bertha only advances 4 feet all day.
Friday, December 6: Shut Down
A plan is made to drill little holes down from the surface to see what might be blocking Bertha's forward progress.
That morning, contractors are drilling two different holes 5 feet in front of Bertha when they learn that workers down below are trying to budge Bertha forward again. After "several phone calls and much confusion," the surface crews are told to stop drilling and move their rigs out of the area.
But attempts to move Bertha forward again end without luck.
The WSDOT inspector on site reports "lots of grease leaking out" of one joint and grease "spraying out" of another joint near Bertha's main bearing. He reports hearing that sand has been found in some of the grease.
Seattle Tunnel Partners has spent the full eight-hour shift struggling to get their $50 million machine to move forward without success. They decide to cancel the graveyard shift.
Saturday, December 7: Ground To A Halt
Seven Weeks Later, And Beyond
The contractor decides to try again. But in moving forward another 4 feet, Bertha overheats and needs to be shut down.
Other than that tiny advance in January, Bertha's been at a standstill for more than three months.
Final Diagnosis And Payment
The contractor and the state have been trading jabs over who's to blame. If WSDOT gave bad information about the project or underground conditions to the contractor, then WSDOT is on the hook for any cost overruns that result, according to John Schaufelberger, a civil engineer who studies megaprojects and is the dean of the College of Built Environments at the University of Washington.
"If the problem is there's a mechanical deficiency in some way in the boring machine, that's the contractor's issue, and who's going to sort all that out is a judge," said Schaufelberger.
Seattle Tunnel Partners have promised to reveal what they believe is behind Bertha's breakdown and how they're going to fix it after Hitachi Zosen Corporation, Bertha's Japanese manufacturer, finishes its investigation.
That announcement could come as soon as this week. In the meantime, repairs are expected to take at least six more months.
Produced for the Web by Kara McDermott.
SR 99 Tunnel Project
SR 99 Tunnel Project
Alaskan Way Viaduct