Bertha breaks through on April 4, 2017. Photo courtesy of Washington Department of Transportation.
On April 4, the enormous tunnel boring machine called Bertha reached a milestone in Seattle's ambitious Alaskan Way Viaduct Replacement project.
After boring 9,270 feet of new tunnel, Bertha broke through to daylight in a pit near Seattle Center. The breakthrough came on the 64th anniversary of the opening of the Alaskan Way Viaduct, the aging highway that the new tunnel will help replace.
Working with the Washington Department of Transportation, Mott MacDonald serves as Project Management Assistant Consultant for this design-build initiative. Mott MacDonald evaluated contractor proposals and played a key role in guiding the alignment of the tunnel.
When the project is completed and the existing viaduct demolished, Seattle residents will enjoy new waterfront views, fewer delays, less traffic congestion, and a safer and more earthquake-resilient alternative for traveling through the city.