Alaskan Way Viaduct Replacement Tunnel (56/105)
Crane lifts the cutter face of the world’s largest tunnel-boring machine to the surface for repairs - March 30, 2015. The tunnel boring machine, nicknamed Bertha, has been delayed since December 2013 after overheating due to damage to the cutterhead’s drive gears, bearings and seals. This delay has lasted for more than a year as the workers have dug a 120-foot vertical shaft down the cutting head to repair it. Digging is scheduled to resume in August after the repairs are complete.
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