The Washington State Department of Transportation announced Monday that Bertha, the tunneling machine digging its way under State Route 99, has passed the halfway point of the project. On Friday, September 30th, the machine tunneled past Pike Place Market, which was the halfway mark of the 9,270-foot tunnel underway.
“This program turned a corner earlier this year,” said Secretary of Transportation Roger Millar. “We’re now closer to the end of the tunnel than we are to the beginning, and everyone on the team is working toward the day when the machine comes out the other side.”
Over the past five months, since April 29th, Bertha has tunneled more than 3,000 feet. The machine is currently approximately 190 feet under 1st Avenue between Pike and Pine Streets. According to Seattle Tunnel Partners, the contractor on the project, the machine will mine a little bit further before stopping to receive about a month of planned maintenance.
During the stop, which is expected to last about a month, STP crews will replace cutterhead tools that are found to be in hyperbaric conditions and inspect machine components.
“Bertha has been steadily on the move and made her way to the second half of the tunnel,” Gov. Jay Inslee said. “This is good progress and I appreciate everyone’s focus on making sure we safely complete this project.”
Bertha is tunneling toward a receiving pit at the north end of downtown at Thomas Street, which is now mostly complete. The final connections to the highway will still need to be made toward completion of the project, but many of the ramps into and out of Bertha’s tunnel are finished. The tunnel operations buildings at each portal are also complete.
STP’s most recent tunneling schedule puts completion at summer 2017, with the work to finish the interior structures of the tunnel and install and test all systems to be finished late in 2018. WSDOT estimates that the tunnel will open for traffic early in 2019.