Feb. 19 afternoon update: Bertha reaches daylight
At midday Thursday, the top portion of the SR 99 tunneling machine’s cutterhead broke through (links to YouTube) the southern wall of the access pit. Crews will continue to mine an additional two feet before stopping to build another concrete tunnel ring.
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.
We recognize that the public has great interest in STP’s repair effort. We will continue to provide photos, video and regular updates about their progress as they work to resume tunneling.
Repair plan resources:
- Video of Bertha's breakthrough (links to YouTube)
- Time-lapse camera view of access pit
- Narrated video (links to YouTube) explains STP’s repair plan in detail
- Time-lapse video (links to YouTube) shows assembly of the massive crane that will lift Bertha to the surface for repairs
- Video of crews chipping (view on YouTube) a Bertha-sized circle on the face of the pit’s southern wall