Many different elements of work must be completed before the SR 99 tunnel is ready for traffic. A previous program spotlight went into these areas of activity in detail. The linear distances of completed work are tracked on the progress tracker, which we are updating monthly (look for an update to the numbers soon).
But numbers only tell part of the story. This photo slideshow takes you inside the tunnel to see the recent progress being made beneath downtown Seattle.
The view of the disassembly pit from inside the tunnel.
Looking south at the top (southbound) deck of the tunnel, beneath Fourth Avenue and Battery Street.
The view looking north from the same spot as the previous photo.
Crews use a spray-on concrete to connect the roadway walls to the circular outer tunnel wall.
The view toward the south end of the tunnel. Here the top (southbound) deck and walls are structurally complete.
The launch pit at the tunnel's south end, which will become part of the future SR 99 tunnel.
Drivers on the viaduct may have caught a glimpse of the recent transformation of the launch pit where Bertha began her journey (see the final photo in the slideshow). This summer, crews working for Seattle Tunnel Partners have been busy transforming the pit into the section of tunnel that will connect the bored tunnel to the SR 99 roadway near the stadiums. We will go more in-depth on this pivotal section of the tunnel in a future program spotlight.
Disassembly of the world’s largest tunneling machine is now complete. This morning crews lifted the final pieces of the 8,000-ton giant out of the SR 99 tunnel’s disassembly pit near Seattle Center. The lift ended more than four months of difficult work, captured in this time-lapse video:
Bertha broke through into the disassembly pit on April 4, 2017, and shortly thereafter built the tunnel’s final ring. Though the machine’s tunneling and ring-building work was complete, crews couldn’t complete roadway construction at the north portal until it was removed. Crews from the contractor Seattle Tunnel Partners have been working around the clock, disassembling the machine to make room for the roadway coming up through the tunnel behind it.
It was tricky, tough, and impressive work, re-positioning the machine and dismantling its 8,000 tons of steel into pieces small enough to lift by crane or pull back out of the south end of the tunnel. The largest lift (or “pick” as crews call it) was 70 tons. Larger pieces required additional cutting on the surface before hauling. Hitachi Zosen, the machine’s manufacturer, will decide what to do with many of Bertha’s components. However, her signature 57-and-a-half-foot steel cutterhead was unique to this project and was cut up and trucked to a local steel recycler. Hitachi Zosen donated pieces of the cutterhead to the Port of Seattle and donated cutting tools and the control panel to Seattle’s Museum of History and Industry.
What happens next
Even while Bertha was still tunneling, crews were building the roadway inside the tunnel and working on electrical and other systems. With the machine completely gone, that work can continue uninterrupted along the 9,270-foot tunnel Bertha dug beneath Seattle. You can follow the work on a new progress tracker page.
WSDOT’s focus is on finishing the tunnel for an estimated early 2019 opening, along with preparing for the Alaskan Way Viaduct’s demolition, the decommissioning of the Battery Street Tunnel, and improving surface street connections at the tunnel’s north and south ends. With disassembly complete, we are retiring the Follow Bertha webpage and updating the program Twitter account. But we will keep the same Twitter handle, @BerthaDigsSR99, because although the machine is gone, the product of her labors remains.
The final lift out of the disassembly pit, Aug. 23, 2017.
Seattle Tunnel Partners is now past the halfway point in disassembling the 8,000-ton tunneling machine Bertha. All of Bertha’s cutterhead is out of the disassembly pit and crews are working their way from top to bottom, cutting sections of the machine and lifting them by crane.
Much of the machine’s trailing gear remains inside the tunnel, out of view of our time-lapse camera. Inside the tunnel, crews are cutting and hauling pieces of the trailing gear out of the tunnel via the south portal. This new time lapse video captures the work happening inside the tunnel.
Work has progressed enough inside the disassembly pit to allow STP to use Bertha’s thrust rams to pull a large section of the trailing gear into the pit. Crews will now work from both outside and inside the tunnel to continue removing the trailing gear, which will help expedite work.
Much of the conveyor system that moved extracted soils from the tunnel onto barges has also been removed. The photo below shows crews lifting the white over-water section of the conveyor last week.
While crews dismantle the machine, work continues on the road inside the tunnel. The photo below shows crews building the upper roadway inside the launch pit near the stadiums, where Bertha began her 9,270-foot tunneling journey underneath Seattle. You can monitor progress here.
In August, we held an open house and online open house to discuss viaduct demolition. We are planning the work, scheduled to begin in full once the SR 99 tunnel opens in early 2019, and we wanted to tell you what lies ahead and ask for your comments and concerns.
Thank you to the 12,000 people who visited our online open house and the 150 people who attended the Aug. 10 open house on Seattle’s waterfront. In total, we received 410 responses to our eight-question survey. We will use … more