July 27, 2015
Bertha, one of the world’s largest tunnelling machines will resume work underneath the US city of Seattle in November, nearly two years after breaking down.
Bertha, at 17.4m diameter, began her journey in July 2013. She was boring a path to relocate a 3.2km stretch of the elevated State Route 99 Alaskan Way Viaduct, built between 1949 and 1953 and which carries around 100,000 vehicles daily.
The elevated section will be moved underground allowing the creation of public space along Seattle’s downtown w