Bertha crews are in a tight spot, and under pressure
Jul 12, 2016, 5:52 AM
Bertha crews are in a tight spot, and under pressure — literally.
As the boring machine sits idle underneath Seattle, crews are crawling, crouching and wiggling to perform maintenance in the front of Bertha. They are about 120 feet below Spring Street in downtown and have been performing maintenance since June 23.
Related: This is the process crews undergo to work on the front of Bertha
The main issue for crews is inspecting cutting tools attached to its cutterhead. The machine has more than 700 of these tools that cut and grind away on underground material. So far, crews have inspected 400 of the tools and replaced 25. Each tool weighs 75 pounds.
Crews are also under pressure while they inspect the cutterhead. To perform maintenance on the front of the machine, a person has to go into a hyperbaric chamber and adjust to different air pressure — similar to what divers must undergo when they dive in deep water.
A worker can spend up to two hours in the high-pressure conditions, then they have to come out for decompression — that takes about 90 minutes. Five crews of seven people work in different shifts to perform maintenance on the space behind Bertha’s cutterhead.
WSDOT said it hopes to have Bertha back up and boring by the end of July.
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