March 31 project update: Bertha lift complete
Posted on Mar 31 2015 7:51 AM
2:35 p.m. update:
On Tuesday afternoon, Seattle Tunnel Partners safely placed the front end of the SR 99 tunneling machine on the repair platform located just south of the access pit. The set-down marked the end of a successful lift process that began early Monday. This time-lapse video shows the lift from a spot just north of the tunnel access pit.
Crews will continue disassembling the machine’s 2,000-ton front end in the coming days, using the massive red crane that completed yesterday’s lift to arrange pieces on the repair site. Repair work will take place south of the pit beneath a large canopy that will soon be moved into place to protect the workers and machine pieces from the elements.
This was the fourth and final lift to bring pieces of the tunneling machine to the surface, a process explained in detail in our narrated video
(links to YouTube). At 2,000 tons, this was also the largest lift crews undertook. In addition to the cutterhead, the newly removed drive unit section includes motors and parts that enable the cutterhead to rotate. It also houses the main bearing and seal system that will be replaced during repairs.
On Monday, Seattle Tunnel Partners lifted the SR 99 tunneling machine’s front end from the access pit. The lifting process began early Monday morning with a series of tests to ensure the massive red crane performing the lift could handle the weight of the 2,000-ton section. The piece began rising from the pit around noon and was visible at the surface a few hours later. By 9 p.m., crews had positioned the piece above the platform where it will be set down for repairs.
STP chose to wait until Tuesday morning to complete the lift with a fresh crew. You can track the conclusion of the lift on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates.