As we speak (write), Bertha is boring under the Alaskan Way Viaduct. We no longer have the opportunity to watch the recovery effort because the greatest activity is happening underground.
WSDOT found a fix for that. They released a video of a drone's flight through the tunnel and up to the machine. Tunnel boring may seem like a simple operation, but while Bertha digs up front, crews build road beds and install systems behind.
You can check the tunnel progress on a couple of maps and sites run by WSDOT. One map shows the entire tunnel, where it has dug and where it intends to dig. The tunnel is divided into ten zones, each one distinctive for a variety of reasons. As of May 4th, 1,455 feet of the 9,300 total are complete.
The part under the viaduct from South Washington Street to Columbia Street is in Zone 2. Bertha now not only has to stay on a straight line but the machine is also diving to remain 15 feet under the foundations. Zone 2 is critical enough to warrant its own page where the progress is foot by foot and panel by panel. Of the 59 rings and 385 feet, they've completed 22 rings and 149 feet.
It'll be a huge accomplishment when Bertha completes Zone 2. But don't get to cocky, there's Zone 3 after that. And then Zone 4. And Zone 5...
· View from a drone inside the SR 99 tunnel [YouTube]
· Tracking Bertha [WSDOT]