Aug. 1 project update: Bertha enters Zone 5
Posted on Aug 1 2016 3:49 PM
Seattle Tunnel Partners mined into Zone 5 of the tunnel drive late last week. Bertha, the SR 99 tunneling machine, has now traveled approximately 3,400 feet and installed 515 concrete tunnel rings. The completed bored tunnel will be 9,270 feet long, and will be made up of 1,426 rings.
The top of the machine is nearly 130 feet below Seneca Street, just west of First Avenue. By the time crews reach University Street – one block to the north – they will be tunneling beneath First Avenue.
Progress updates are posted each Monday and Thursday on our Follow Bertha page. You can also track tunneling progress on Twitter @BerthaDigsSR99.
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