When the underground borer Bertha gets stuck under Seattle – for a year

The construction of massive infrastructure underground can be impressive but it doesn’t always go as planned:

A year ago this month, North America’s largest tunnel-boring machine got stuck just 10 percent of the way through a 1.7-mile-long dig under downtown Seattle. Throughout 2014, engineers have been plugging away on an ambitious plan, outlined in a Popular Mechanics feature, to free the mechanical marvel and get the project going again.

But today, Bertha remains stuck under the city. And according to an update from The New York Times, crews monitoring the project to free the machine have noticed something alarming: one inch worth of settling in the downtown district under which Bertha now sits…

Instead, investigators eventually concluded that Bertha was overheating—that grime and gunk had gotten past bearing seals, entered the machine, and muddied the operation. Engineers still aren’t sure why all this happened to the 326-foot-long machine, but they decided they had replace not only the seals but also the $5 million main bearing.

But just getting to Bertha, which sat more than 60 feet below downtown Seattle near the stadium district and the waterfront, posed a serious problem. Crews could go through the painstaking, time-sucking process of disassembling the machine from behind to make the fixes, but instead chose to dig a 120-foot-deep access pit in front of Bertha.

It shouldn’t be too surprising that such a big project could lead to a problem that doesn’t have a quick fix. Putting together a machine this size is notable in itself and getting it back on track likely requires a lot of careful planning and long hours. Yet, these sorts of projects tend to go on without much attention until they are done and people experience the benefits. Unless something goes wrong. It would be interesting to see how Seattle responds to the delay and if someone is blamed for the problems, what kind of negative consequences they suffer.

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