March 9 project update: New 360-degree video takes you inside the tunnel as Bertha enters Zone 10

Posted on Mar 9 2017 10:00 AM
The countdown is on as Bertha, the SR 99 tunneling machine, mined into the 10th and final zone of the 9,270-foot tunnel drive this week. With 1,294 concrete tunnel rings installed in the ground behind her, Bertha is less than two blocks from the disassembly pit where her journey will end.
 
How is the interior of the tunnel shaping up? And how is Bertha doing? It’s probably best if we show you. Click below to join Program Administrator Joe Hedges on a 360-degree tour of the project. Move your smartphone up and down to move around the tunnel. Or, if you’re on a computer, grab the picture with your mouse for a 360-degree view of the work that’s happening out of sight, underneath Seattle.   
 
 
Looking ahead
 
It’s still too early to predict when Bertha will reach the disassembly pit. Seattle Tunnel Partners’ most recent schedule shows that tunnel boring is slated to end in May, but mining rates will continue to vary based on maintenance needs and ground conditions.
 
There’s still plenty of work to do after tunnel boring is complete. STP will begin disassembling the tunneling machine soon after the cutterhead breaks into the pit. They will remove the machine in small pieces and haul them away by truck, a process that will take several months.
 
Meanwhile, crews will continue building the double-deck highway inside the tunnel. This work is completed in different stages, as shown in our weekly interior structures report. The roadway deck is now at the southern edge of Pike Place Market, or nearly 50 percent complete.  
 
Crews are also installing mechanical, electrical and plumbing systems that must be completed before the tunnel can open to traffic. This is a big job that is scheduled to last well into 2018. 
 
As construction continues, WSDOT and STP will begin an extensive commissioning program. This involves a series of thorough inspections, tests and quality verification procedures to ensure the tunnel systems are functioning properly.  
 
Based on STP’s schedule, the tunnel is projected to open in early 2019. Progress updates are posted on Mondays and Thursdays at our Follow Bertha page. You can also follow Bertha on Twitter @BerthaDigsSR99.