The cutterhead will be lifted and moved over the rescue pit, where it will be rotated 90° and lowered to be rejoined with the rest of the TBM.
For articles I've previously submitted, from the arrival of the machine from Japan to final breakdown, type "Bertha" in the Blog Search Engine located in the right margin.
Out of the Pit!
Following Bertha's breakdown, a rescue pit was created in front of the TBM. Bertha was then driven into the pit, where the front end cutterhead assembly was retrieved for repairs. In this nighttime photo taken in March 2015, Bertha's head end is suspended above the tunnel rescue pit.
The rest of the machines will remain in the ground while repairs are conducted at the surface.
Mammoet Modular Lifting Device
This machine is so huge, it literally takes another massive crawler crane, traveling on a thick bed of "crane mats" to construct it! The Modular Lifting Device will pick up and move the 2,000 ton cutterhead assembly like it were a can of soup!
The hydraulic push-pull cylinder extends to the specially designed skid bed, locks in, and pulls the device along, using massive amounts of lubricating grease!
strandjacks grasp and pull the lifting cables, inches at a stroke, to lift and lower Bertha's components.
Putting Bertha Back Together
Back into the Pit!
Just after 9 a.m. Monday (24th) the impressive Mammoet Modular Lifting Device took up the slack in the lifting cables, and began the slow process of jacking the drive motor cutterhead assembly off the repair platform, advancing toward the rescue pit.
Photo captions tell the story ...
The lifting device will remain in place whilst the cutterhead assembly is reconnected to the main body of the TBM.
Progress Beyond the TBM
|Sunday August 24, 2015, Courtesy OxBlue & WSDOT|
Seattle Tunnel Partners has issued this new timeline, to resume digging the Highway 99 tunnel:
• August: Lower front end into 120-foot-deep rescue pit. ☑
• September: Connect front-end drive parts, hoses, pipes and cables to Bertha’s body.
• October: Open-air testing inside the vault.
• November: More testing, with dirt in the vault.
• Restart boring November 23rd.
• January 19, 2016: Stop at a “safe haven” just before boring beneath the Alaskan Way Viaduct, for four weeks of inspection and adjustment.
• February: Drill under the viaduct, which may be closed to vehicular traffic, seven to 10 days.
• November 29, 2016: Bertha reaches the North Portal at Harrison Street.
• June 2017: Road decks, walls and ceilings done, followed by signals, ventilation and testing.
• March 9, 2018: Tunnel ready for traffic.