11:39 AM: If you’ve been on the Alaskan Way Viaduct this morning and noticed a dust cloud – the Highway 99 tunneling machine is “preparing to break through” the wall of its repair pit, according to a Twitter update a few minutes ago. Earlier this morning, WSDOT published a web update saying the machine had moved 14 of the 20 feet it needs to go to break into its repair pit. It had warned that they expected the machine to overheat and have to stop down, but aside from a stopdown reported last night so other work could be done in the pit, there’s been no word of that happening. WSDOT says it’s switched the pit camera to more frequent updates – every five minutes – so you can check in here (left-center frame).
12:44 PM: And while we were away from the desk for a bit:
The top of my cutterhead has broken through the wall. I'll dig 2 more ft. before stopping to build a ring. pic.twitter.com/SVcThsimnv
— Bertha (@BerthaDigsSR99) February 19, 2015
Online, WSDOT adds:
This is just the beginning of the repair effort being led by Seattle Tunnel Partners and manufacturer Hitachi Zosen. The machine will continue to move forward in 6 ½ foot increments, stopping to build rings on its way into the pit. When the front end of the machine is fully exposed, crews will begin the disassembly process. STP has told us that taking the machine apart and lifting it to the surface will take significant time and effort.
ADDED 5:22 PM: WSDOT offers this video including the first glimpse of the machine’s cutterhead (most visible around 1:15 in):
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