Bertha timeline: From conception to tunnel completion

SEATTLE — January 2008

Washington Gov. Christine Gregoire announces state will take down Alaskan Way Viaduct in 2012.

January 2009
State of Washington, King County, city of Seattle and Port of Seattle announce agreement to replace Alaskan Way Viaduct with bored underground tunnel.

May 2009
Governor Christine Gregoire signs measure authorizing $2.8 billion in state funds for tunnel project.

April 2013
The world's largest tunneling machine, now christened "Bertha," arrives in Seattle.

July-December, 2013
Bertha begins drilling. Read more. Initial plans call for drilling to take 14 months. Bertha travels 9.270 feet of planned 9,270 feet.

December 2013
Bertha components shut down during attempts to drill at high power. Drilling halted. Seattle Tunnel Partners operators try to get Bertha moving again. Drill running at elevated temperatures.

January 2014
Steel pipe is blamed for tunnel stoppage. The Seattle Times reports steel pipe struck by Bertha was put there by WSDOT engineers to study groundwater and included in plans provided contractor prior to tunnel bid submission. The contractor says Bertha's cutting teeth struck the 119-foot pipe, 8 inches in diameter, on Dec. 3, 2013. But WSDOT disagreed with the assertion that the pipe caused the damage, and the issue is being litigated. The machine overheated and came to a halt three days later.

February 2014

WSDOT announces Bertha seals and bearing damaged, likely causing overheating problems, no schedule for repairs or resumption of drilling. Seattle Tunnel Partner project director Chris Dixon says contractor hopes to complete repairs and resume drilling by September 1.

March 2014
STP continues working with Bertha manufacturer to determine best way to repair drill and resume operations. Plans call for 120-foot-deep pit ahead of drilling machine to facilitate repairs. WSDOT digs 60 narrow test holes to check for historic artifacts ahead of repairs.

Related: Ancient artifacts could be latest issue for Bertha

April 2014
Seattle tunnel critic files lawsuit to stop repairs on Bertha. WSDOT, STP announce tunneling will not resume until March 2015.

Related: With Bertha at a standstill, project managers find time to practice their golf swings 

May 2014
The Washington State Department of Transportation tells the Seattle City Council that damage to Bertha will delay its progress further. "Even though the damage is more than they were expecting to find, it's not more than they were planning to repair at this point," said Todd Trepanier with WSDOT. Read more.

December 2014
A large crack discovered on a Pioneer Square street (on King Street near 1st Ave. S.) possibly tied to the Seattle tunnel project prompted a temporary closure as officials scrambled to respond. A map details the extent of the settlement shows the crack is just above the epicenter of the settling.  Read more.

Photos: Sitting idle for two years

July 2015
Crews began installing four 40-foot-tall yellow ventilation stacks at the south portal operations building. Still no word on when Bertha will resume. Read more.

Related: You might actually agree with McGinn, Sawant on Bertha

October 2015
Crews prepping to move Bertha forward. Bertha is still at the bottom of its access pit, but crews are beginning to treat the ground in front of the tunneling machine with water and cement. Read more.

The Washington State Department of Transportation files lawsuit against Seattle Tunnel Partners. WSDOT asked STP to agree to a stay of the lawsuit until the project is completed. Former Attorney General Rob McKenna says regardless of when the case actually goes to court, the matter will not be over any time soon. Read more.

November 2015
Bertha was originally slated to resume again on Nov. 23 (three months late), but the timeline is pushed another month. WSDOT says it's frustrated. Read more.

Related: Bertha on schedule to resume tunneling by Christmas

December 2015
STP and manufacturer Hitachi Zosen completed repairs to the machine in December 2015. Seattle Tunnel Partners Project Director Chris Dixon said repairing Bertha has taken longer than anticipated. Read more.

Testing on Seattle's tunnel boring machine was stopped temporarily due to a broken arm. Bertha resumes before Christmas. Read more.

January 2016
On Jan. 13, the Washington State Department of Transportation announced a sinkhole developed shortly after Bertha began digging again. The hole was spotted about 100 feet south of Bertha's current position. Read more.

Related: Seattle tunnel contractor downplaying Bertha’s sinkhole

Related: Bertha delays nothing compared to those of early Seattle

February 2016
Bertha resumes mining. The Washington State Department of Transportation has allowed the contractor, Seattle Tunnel Partners, to move forward and place a total of 25 rings.  Read more.

Despite the approval to move forward, the stoppage over the past month has caused another rift between WSDOT and the tunneling contractor.

"There is a disagreement with Seattle Tunnel Partners on this. It's not the first time we have disagreed," said Todd Trepanier with WSDOT. "They think the stop was not appropriate, and they would like to be compensated for the time it has cost them." Read more.

Related: WSDOT head Lynn Peterson fired

April 2016
Bertha's journey resumes on Friday, April 29, prompting the closure of Highway 99 for at least two weeks. It means at least 90,000 daily commuters had to find an alternate commute. WSDOT to closely monitor Seattle's roads.

May 2016
Bertha tunnels 292 feet since Seattle's viaduct closed for two weeks. Read more.

Engineers determined that tunneling under the viaduct did  not cause any issues with the aging structure. Read more.

Related: Seattle tunnel progress a major contrast to past problems

June 2016
Bertha nears another maintenance stop and a 3,000-foot milestone. Read more.

July 2016
Executives at Hitachi Zosen, the company that built Bertha, tells The Seattle Times that Bertha was working perfectly before running into a metal pipe near South Main Street. Read more.

WSDOT asks for $60 million more in funding and more time to finish the tunnel. "We're making good progress, we've had a delay that's affected our schedule, that's affected our budget," acting Secretary of WSDOT Roger Millar told the state legislature's joint transportation committee. "What we are looking at is a project that will be open to traffic in 2019." Read more.

August 2016
Bertha has tunneled 4,000 feet and approaches Zone 6. Crews have installed 607 concrete rings to form the tunnel walls. Read more.

September 2016
After a two-week break, Bertha is tunneling below Seattle's waterfront again. The tunnel machine was at a standstill 170 feet below First Avenue and Union Street for maintenance to the cutterhead. Read more.

The Seattle Times reports that the contractor who is operating the machine originally only had insurance until Aug. 31. That was the day the new SR 99 tunnel through Seattle was suppose to be completed. Bertha stops below First Avenue and Union Street for maintenance. Read more.

October 2016
Bertha has bored more than 5,000 feet under downtown Seattle, and has stopped under one of the city's more popular destinations. – Pike Place Market. Read more.

November 2016
Bertha reaches one-mile mark. The machine is located 200 feet below First Avenue, north of Stewart Street. Read more.

Bertha reaches deepest point in journey and is about 60 percent complete. Read more.

January 2017
Crews with Seattle Tunnel Partners resumed mining under Seattle, following 10 days of maintenance on Bertha the boring machine. Read more.

March 2017
Bertha's route had to be corrected after it was discovered that the boring machine had verred 6 inches off its alignment. Read more.

April 2017
Bertha expected to reach its final destination near the intersection of Sixth Avenue North and Thomas Street, where the drill will bust through a concrete wall into a receiving pit.

KIRO