Bertha has left the tunnel, finally. What’s next?

This time-lapse video captures the difficult and challenging work to disassemble the world’s largest-diameter tunneling machine. For four months, crews cut, hoisted and trucked away 8,000 tons of the machine's equipment and steel, removing it from inside the tunnel it had built. Up next – finishing the double-deck highway inside and installing all the operating systems to open Seattle's new SR 99 tunnel by early 2019.

As of August 24, 2017, Bertha has been completely disassembled. Bertha was working for nearly 4 years under the objective of a much larger project, The Alaskan Way Viaduct Replacement Project. If you weren’t keeping up with Bertha and what the largest tunnel boring machine has been up to, less than 215’ below downtown Seattle [view the simulation below], here’s the highlight reel.

  • 2008 – The Alaskan Way Viaduct Replacement project officially began (primarily legislation, planning, mitigation, and demolition)
  • 2009 – WOSCA building demolition
  • 2010 – Pier 48 demolition
  • 2011 – SR 99 Tunnel project kicked off (mitigation and structural work)
  • 2011 – Demolition and repair of the South end of the Viaduct
  • 2012 – Cedarstrand building demolition
  • 2013 – Bertha began digging, boring, tunneling, and doing what “she” does. (Bertha was named after Bertha Knight Landes, elected mayor of Seattle in 1926)
  • 2014 – North Tunnel Access construction began
  • 2016 – South Tunnel Access construction began
  • 2017 – Bertha completed her boring and tunneling

…so, what’s next?

  • 2016 – South Tunnel Access construction began
  • 2017 – Bertha completed her boring and tunneling
  • 2018 – Connections between Tunnel, Access, and surface streets
  • 2019 – SR 99 Tunnel completion and open to the public
  • 2019 – Demolition and decommissioning of Alaskan Way Viaduct
  • 2019 – Begin Alaskan Way Surface Street Project
  • 2023 – Complete Waterfront and Alaskan Way Street

A Glimpse into 2023

When the entire Alaskan Viaduct Replacement project is completed (2023), Seattle will have a brand new 1.7-mile-long tunnel, an additional mile-long stretch of highway at the south end of the tunnel, new Alaskan Way street, new Alaskan Way Waterfront, Elliot Bay Seawall, and a seismic-safe way to travel. The current budget stretching into 2019 (when the tunnel will be open to the public) is set at $3.2 Billion. Another $149 Million may be needed to complete the program, estimated 2023. We can’t wait to see the entire project completed in all of its glory (and to have some major construction wrapped up around here). What are your tunneling thoughts?

Extras for your entertainment

Did you know? Bertha actually built the tunnel behind her as she bored through the earth.

This video shows how Seattle Tunnel Partners crews build the highway inside the SR 99 tunnel in Seattle. For more information, visit SHOW MORE
WSDOT simulation, taking you underground along the crown of the tunnel.

The Washington State Department of Transportation, in partnership with the Federal Highway Administration, King County, the City of Seattle and the Port of Seattle, is leading a program to replace the Alaskan Way Viaduct section of State Route 99, which runs along Seattle's downtown waterfront.

Visit Milepost 31 for a museum-like tour of projects that shaped Pioneer Square and the SR 99 Tunnel project.