Share this story...
Bertha
Latest News

Bertha beats Battery Street, now faces monorail

The yellow structure above the tunnel in this graphic is the Battery Street Tunnel. It is about to pass underneath the monorail piles. (WSDOT)

Bertha just passed under the Battery Street Tunnel and is about to move below the support structures for the monorail in downtown Seattle.

At this point, Bertha is making a run toward the surface. The machine was 90 feet beneath the Battery Street Tunnel this week and 211 feet below Bell Street just a couple of weeks ago. That’s just short of its deepest point — 215 feet below the surface. Bertha is expected to be about 90 feet below the support piles for the monorail — along Fifth Avenue — in the coming days.

Related: Bertha passes under Bell Street

Bertha has traveled 7,692 feet forward since beginning, installing 1,175 rings (out of 1,426). That means the machine has 1,578 feet to go to reach its end goal. WSDOT reports that the ground has remained stable along the tunnel route under Seattle.

Where’s Bertha now?

The boring machine is currently moving below two apartment buildings — one constructed in 1998 and another in 1949 — and an office building built in 1947.

It’s a relatively short distance, spanning about a block. When crews reach Denny Way, the machine will leave zone 9 and enter zone 10 — the final stretch of the journey under Seattle.

At the other end of the tunnel, separate crews have already begun constructing the two-level roadway inside the tunnel. They are also installing electrical and plumbing. So far, 3,800 feet of new roadway has been built. That runs from the southern end of the tunnel to Pike Place Market.

Most Popular