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Seattle Tunnel Partners has reconnected the SR 99 tunneling machine’s 2,000-ton front end to the section that remained in the access pit during repairs. With the two sections of the machine now bolted together, crews from Mammoet have unhooked the front-end piece from the massive red crane that performed this week’s lift.Photos of the lift are available on Flickr, and the time-lapse video below shows the whole thing in 62 seconds.Significant work remains for crews tasked with reassembling the machine. Three large pieces of the machine’s outer shield will be lowered into place for reassembly in the coming days, according to STP’s most recent schedule. Crews also must weld the pieces back together, in addition to the lengthy task of reconnecting the hundreds of wires and hoses that are integral to the tunneling operation. STP and manufacturer Hitachi Zosen will conduct a series of tests following reassembly to ensure the machine is ready to resume mining.— more —
3:20 p.m. update: Seattle Tunnel Partners and crane crews from Mammoet have successfully lowered the 2,000-ton front end of the SR 99 tunneling machine to a platform at the bottom of the access pit.Crews will now use the crane to fine-tune the position of the piece. When that process is complete, they will begin reconnecting the piece to the portion of the machine that remains in the ground.The effort to return the tunneling machine's front end to the 120-foot-deep access pit began early Monday morning. Crews started by vertically lifting the piece, which includes the machine’s cutterhead, motors and the new main bearing assembly. The crane then moved horizontally on its rails to the north. When the piece was above the pit, crews rotated it to a semi-vertical position and lowered it partway into the pit before breaking for the evening. Work resumed early Tuesday morning, with the piece reaching the bottom of the pit Tuesday afternoon.Three pieces of the machine’s shield that remain at the surface will be lowered and reinstalled in the coming days, according to STP’s latest schedule. After the machine has been reassembled, STP and manufacturer Hitachi Zosen will conduct a series of tests will follow reassembly to ensure the machine is ready to resume mining.The tunneling machine's front end as it nears the bottom of the pit on Tuesday afternoon.***Original post: On Tuesday morning, Seattle Tunnel Partners and crane crews from Mammoet resumed lowering the front end of the tunneling machine into the access pit.The effort to return Bertha to the 120-foot-deep access pit began early Monday morning. Crews started by vertically lifting the piece, which includes the machine’s cutterhead, motors and the new main bearing assembly. The crane then moved horizontally on its rails to the north. When the piece was above the pit, crews rotated it to a semi-vertical position and then lowered it partway into the pit before breaking for the evening.We’ll continue to provide updates here and on Twitter as the work progresses.The view from the top of the crane responsible for lowering machine parts back into the access pit.— more —
5:30 p.m. update: The front end of the tunneling machine has been partially lowered into the access pit. Crane crews will break for the evening and lower the piece to the bottom of the pit on Tuesday. Look for an update in the morning.12:34 p.m. update: With the front end of the tunneling machine now suspended above the access pit, crews have begun rotating it vertically. When the piece is in position, crews will begin lowering it toward the bottom of the pit. Track the action on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates.A shot of the machine's front end suspended over the access pit.11:14 a.m. update: The front end of the tunneling machine has been safely lifted off the ground. Crews have begun moving the crane horizontally toward the access pit. You can track the action on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates.***After completing motor installation over the weekend, Seattle Tunnel Partners is nearly ready to lower the SR 99 tunneling machine’s newly reassembled front end into the access pit.Crane crews have finished connecting the 2,000-ton piece to the crane and are performing final tests. They expect to begin the lift later this morning. Lifting and lowering the piece into the 120-foot-deep pit could take 14 hours or more, but there is no set schedule. Crews will take as long as necessary to prepare for and safely complete their work.The front-end section is the largest of four pieces that will be lowered into the pit for reassembly in coming days. The section being lifted today includes the machine’s cutterhead, motors and the new main bearing assembly.The crane doing the lifting was built by Mammoet, a firm that has performed similar lifts around the world, including the successful recovery of a Russian nuclear submarine from the bottom of the Barents Sea. Equipped with nearly seven miles of steel cable, the crane lowering Bertha into the pit is capable of lifting more than 2,400 tons. This video (links to YouTube) shows what it looked like when Mammoet lifted this section of the machine from the pit on March 30. This narrated video (links to YouTube) explains the entire repair sequence in detail.Once the front end of the machine is in place at the bottom of the pit, crews will begin reconnecting wires, hoses and cables to the portion of the machine that remains in the ground. STP’s latest schedule shows that three pieces of the machine’s outer shield will be lowered into the pit for reassembly in the days following the front-end lift. A series of tests will follow reassembly to ensure the machine is ready to resume mining.— more —
This week, at the south entrance to the bored tunnel, Seattle Tunnel Partners is pouring concrete for a section of the future southbound highway. On one hand, the pouring of concrete (also known as a "concrete placement”) is nothing extraordinary – it’s a common occurrence on a project that will use enough concrete to build nine football stadiums. But their frequency belies the complex choreography that goes into executing each pour successfully. Since concrete plays … more
Keeping the public informed about our work to replace the Alaskan Way Viaduct is an important part of what we do every day. Our goal is to give you as much access as possible to this amazing project, which is why we regularly post updates, photos and videos of our progress. We even offer walking tours from our information center, Milepost 31, to a viewing platform that overlooks the pit where tunneling began in summer 2013.
Unfortunately, there’s one frequently received request … more
As reported elsewhere on our website, work to access and repair the SR 99 tunneling machine is coming along. We’ve heard from some people that Seattle Tunnel Partners’ repair plan is hard to picture. Enter STP’s Chris Dixon, who was nice enough to narrate a video that explains what crews are doing to resume tunneling by March 2015. Watch it on YouTube or download a WMV file.
Seattle Tunnel Partners repair work plan (pdf 4.8 Mb) … more
We’ve been asking you to do your part to reduce congestion when SR 99 closes for four days starting Friday night, Aug. 22. That includes things like changing your commute habits and choosing an alternate way to get around.
But what are we, the agencies tasked with keeping traffic moving during this closure, doing to help? Quite a bit, actually. Here’s a roundup of some of the steps we’re taking to help you and your fellow commuters through the closure.
Washington … more
Less than three years ago, crews demolished the southern mile of the Alaskan Way Viaduct. When they did, they shifted traffic onto a new section of State Route 99 south of downtown Seattle.
Much of that new section of SR 99 is permanent, but the piece west of the stadiums is temporary. This curving stretch of road takes drivers around the SR 99 tunnel construction site and connects to the remaining section of the viaduct near South King Street. It’s nothing fancy, but it’s … more
Just in time for Bike Month, we opened a new permanent connection between the on-street bike lanes south of South Atlantic Street and the shared-use path from South King Street. Here’s a map that shows the improvements, which include:
A dedicated, 14-foot-wide shared-use path with improved paving.
A separate northbound and southbound path for more efficient navigation.
Signs warning of vehicles crossing the intersection of … more
You may have noticed more construction along State Route 99, just north of the Battery Street Tunnel. That work is part of the SR 99 Tunnel Project, but it has its own name – the North Access Project. It’s also being built under a completely different contract than the one we have with Seattle Tunnel Partners, the contracting team responsible for most of the tunnel work. A map of major contracts within the program can be found here (pdf 1.1 Mb).
Our contractor for the North … more