Bertha undergoing a $125 million underground repair

[LiteYear]

Figured this one would interest the general engineering audience:

Fixing a 7,000-Ton Drill

A 7000 ton tunnel boring machine nicknamed "Bertha" has been stuck under downtown Seattle since last December after it struck a pipe and a seal failed. Work is under way to enact a fix: a vertical shaft is being excavated to reach the stricken TBM, supported with massive concrete pilings. As I understand it, once the shaft reaches the depth of the TBM, the TBM will be inched forward, cutting through those pilings, until the front of it reaches the centre of the shaft. The damaged cutting head will then be detached, lifted up to the surface, and a new, more powerful cutting head will be lowered in place.

Not only is the engineering involved in planning and performing the fix quite extraordinary, the background debate about who is responsible for the colossal repair bill will be an interesting fight to watch.

 

[ornerynorsk]

Realtime webcams and updates here:

http://www.wsdot.wa.gov/Projects/Viaduct/About/followbertha

It is better to have enough ideas for some of them to be wrong, than to be always right by having no ideas at all.

 

[IRstuff]

Someone posted something about this a few months back

TTFN
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Need help writing a question or understanding a reply? forum1529

 

[LiteYear]

Ah yes, couldn't find it on the first search:

http://www.eng-tips.com/viewthread.cfm?qid=364499

Well, in 3 months Bertha hasn't moved, but she is closer to seeing the light of day.

 

[davefitz]

regarding the repair bill , there is no doubt whatsoever that the Seattle taxpayer will be saddled with it. Every Seattle project , whether executed or even just simply proposed, ends up soaking the Seattle/ King county taxpayer way in excess of the original projections. The contract T+C's seem to be produced by a kindergarten class.

"Whom the gods would destroy, they first make mad "