Highway 99 tunnel: Repair-pit digging’s done, says WSDOT

(At 3:39, WSDOT’s video shows excavation on its final day, today)
Just in from WSDOT, the latest Highway 99 tunnel news: The pit being dug to lift out the tunneling machine’s damaged cutterhead has reached the desired depth, 120 feet.

… Approximately 20,000 cubic yards of material was removed from the ground over the course of excavation, which began in mid-October. With excavation complete, crews can begin construction of the concrete cradle at the bottom of the pit. The cradle will support the machine after it moves through the pit’s southern wall, which is about 20 feet thick.

STP plans to tunnel through the concrete wall. The length of time it takes Bertha to reach the pit will depend largely on her ability to mine through and digest the concrete. If she’s unable to mine through the wall, STP will create an opening from within the pit to give her an unobstructed path forward. Once inside the pit, crews will use the massive red gantry crane … to hoist the front end of the machine to the surface for repairs.

Today’s update also says, “Settlement levels near the pit remain stable.”

(WSDOT photo)
Meantime, for more info on that giant crane – which you’ve likely noticed right next to the Viaduct downtown – check out Seattle Times (WSB partner) transportation reporter Mike Lindblom‘s story from two weeks ago.

jwright January 30, 2015 (5:37 pm)

Glad to hear they are making progress! We’re that much closer to project completion. Eagerly awaiting to hear how subsequent commenters will spin this as a sign of the impending apocalypse.

Marge Evans January 30, 2015 (5:45 pm)

unreal. don’t take her out. bury her and move on.

JayDee January 30, 2015 (6:25 pm)

@jwright – 5 minutes, apparently.

I am a little curious why they don’t make it as easy as pie for Bertha to drill into the pit..why wait for failure?

Give Bertha another chance, and if she stops under an immovable downtown skyscraper, then let’s call it a day. Vultures are already flocking around Bertha…STP says the Pioneer Sq. settlement has nothing to do with dewatering, but instead “tectonic/landslide” forces. It has to pass the straight-face test and that claim doesn’t.