Feb. 18 afternoon update: Bertha digs on

Posted on Feb 18 2015 4:21 PM

Since mining resumed at 10:15 p.m. Tuesday, Bertha has successfully moved forward more than six feet and work is progressing as planned. Crews stopped mining this afternoon to begin building the SR 99 tunnel’s 151st concrete ring. Mining will resume after the ring has been built.  

Seattle Tunnel Partners and tunneling machine manufacturer Hitachi Zosen are continuing to follow strict protocols as they mine through the access pit’s southern wall. These protocols are designed to prevent overheating or further damage to the machine as it mines through 20 feet of unreinforced concrete to reach the interior of the pit.

We continue to closely monitor the surrounding area as this work proceeds. 

Previous updates

Feb. 18, 2015 project update - Bertha on the move

Feb. 13, 2015 project update - Safety at the forefront

Feb. 13, 2015 project update - Long-term traffic impacts on SR 99: lane closure begins March 7 through late May

Feb. 12, 2015 - Incident at tunnel's north portal work zone

Feb. 9, 2015 project update - Cradle awaits Bertha's front end

Jan. 30, 2015 project update

Archive of previous updates