SEATTLE -- Now that the Bertha access pit has been excavated, officials say the next step in reaching the SR 99 tunneling machine is to dig through the concrete wall at the bottom of the pit.
WSDOT tweeted a photo of the 120-foot deep access pit which crews finished excavating on January 30th.
Alaskan Way Viaduct Replacement Program administrator Todd Trepanier says Seattle Tunnel Partners have been building a concrete cradle at the bottom of the pit. This will support the machine after it moves through the pit's 20-foot thick southern wall.
For months the world’s largest tunnel-boring machine has been damaged and sitting idle underneath Seattle. Setbacks have plagued the multibillion-dollar project.
Once contractors reach Bertha, they will replace the machine's damaged cutter head and try to get it digging again.