Bertha maintenance crews are working under pressure to get the job done
Apr 1, 2016, 5:49 PM | Updated: 6:18 pm
Bertha crews must enter these pressure chambers located inside the boring machine in order to work in tight spaces behind the cutterhead. (WSDOT)
(WSDOT)
Bertha is sitting idle, but maintenance crews aren’t as they work to get the boring machine ready to dig underneath Seattle’s viaduct.
And to do that, crews have to undergo an unusual procedure to work on the machines. Crews are working in hyperbaric conditions located directly behind the cutterhead. This means the pressure where they are working is greater than the normal atmospheric pressure humans experience. It is similar to conditions divers experience when going into deep conditions.
The task at hand is to clean material from the cutterhead openings and replacing parts that need to be replaced.
Crew members must complete a physical examination before even working in the pressurized conditions. Then they must go into a pressure chamber for up to an hour to allow their bodies to adjust to the new conditions. These chambers are located inside Bertha.
Five or six crew members can go into a chamber at a time, then spend up to two hours working in the pressurized conditions before they must come back out and return to normal pressure. Decompression can take up to 90 minutes. So far, 60 pressurized shifts have been completed,and a person can only do one shift per day.
