SEATTLE, Wash. — A contractor found itself without any Bertha insurance this week, but that didn’t stop the world’s largest boring machine. Bertha actually stopped itself.
Bertha is now beneath these downtown Seattle attractions
The Seattle Times reports that the contractor who is operating the machine was without Bertha insurance for one day on Sept. 1. This is because the tunnel was originally expected to be competed on Aug. 31, and the initial insurance coverage only went out that far. The coverage was soon extended to Oct. 10.
But a new Bertha insurance plan is needed, and is expected to be worked out by October.
Bertha is stopped about 170 feet below First Avenue and Union Street, again, for maintenance. It is the third time the machine has stopped for inspections of its cutterhead — the first was shortly after it resumed boring around the new year, then in June. The purpose of the maintenance is to replace cutter tools at the front of the machine. These are larger than tools replaced in the past — they can weigh up to 600 pounds. The current medium that Bertha is digging through is sand and gravel — it was previously in predominantly clay. That sand and gravel wears down the tools faster.
Unlike previous stops, crews are not required to go into a hyperbaric chamber to do the work. Previous maintenance required people to go into an environment with much higher air pressure.
This story was written by Dyer Oxley with MyNorthwest.com. Read more stories like it by clicking here.
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