Bertha 14 feet from fresh air, improvements to finish project

Bertha dug for the first time in more than a year Tuesday night and has progressed six feet.

The tunneling machine dug three feet Tuesday night, followed by an additional three feet on Wednesday, according to the Washington State Department of Transportation.

Bertha will receive some much-needed upgrades once the tunneling machine is lifted out of the hole it has sat in for months.

About 14 feet of concrete stands between Bertha and fresh air. Once the machine is exposed, workers will begin disassembling it and lifting it to the surface, Seattle Tunnel Partner’s Chris Dixon said.

Seattle tunnel opponents: No gas tax dollars for Bertha

“We have the ability to remove the cutter head and the cutter drive unit as one piece, but in order to lift those out, we’re going to be disassembling the front part of the shield [in three pieces],” said Dixon.

When Bertha is out of its hole, workers will replace the machine’s bearings, seals and add new components to try and keep the world’s largest tunneling machine from overheating. Additional steel plates will be added to the machine’s components to add strength, said Dixon.

According to the latest timeline, tunneling should resume in April. That’s been the working date since last year, but that didn’t factor in the delays workers experienced handling the groundwater in the repair shaft.

Dixon is confident the project will get back on track. “The project’s very, very important, we’re going to complete the project, we’re going to complete it successfully.”

So here are the key facts when considering all of this:

First, we have no idea how far this 14-month delay has cost the project. No one will say exactly how much this has pushed the budget or who will pay for it, though the city and the state are quite certain Seattle Tunnel Partners will be on the hook. But that might be up to a court to decide.

Bertha has made it about 1,000 feet. It still has 8,000 feet to dig before it pops out near Seattle Center.

Under the original timeline, the tunneling would have been finished by now, and the tunnel would have opened to drivers in December.

The latest estimate is that it will be August of 2017 before the tunnel opens.

The good news is that the work on either end of the tunnel continues to go forward, and most of that work has been completed.

That’s why the state said this project is 70 percent complete, even though the 30 percent left is hardest part and represents the biggest undertaking in the entire project.

Below, WSDOT crews cut into the pit wall where Bertha will eventually emerge. The process is similar to scoring a surface before you cut into it, WSDOT reports. The process will allow concrete to break away in a controlled manner.