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Fixing a 7,000-Ton Drill
An anonymous reader writes: At the end of last year, we discussed Bertha, the world's largest tunnel boring machine. During an effort to drill a viaduct beneath downtown Seattle, the machine — clocking in at 7,000 tons, 57.5 feet in diameter, and 326 feet long — got hamstrung by an 8-inch-diameter steel pipe. The complexity and scope of the repair plan rivals that of the project itself. "The rescue operation (workers call it "the intervention") began in late spring with construction on the shaft to reach Bertha. Workers have been sinking pilings in a ring to prevent the shaft from collapsing, using 24,000 cubic yards of concrete — enough for a medium-size office building. Once that ring is complete, digging on the shaft will start. When the shaft is ready, Bertha, which is damaged but still operational, will be turned back on so she can chew through the concrete pilings to reach the center of the shaft. There, the machine will rest on a cradle where workers can detach the front end and hoist it out." That detachable front end? It weighs about 2,000 tons by itself. The repair bill is estimated at about $125 million.
Surely they could have used 3D printing to make a new Bertha? Preferably from fair-trade private asteroid dust?
Tell 'em that their Big Bertha is busted and they need a new one.
If that doesn't work, try Ballmer.
Blight gas incoming.
Actually, something else is causing the seals to fail on the bearings and master bearing. The sampling pipe was the original theory but it could not account for the damage being done.
FTFA “Contractors are not entirely sure what’s happening to the seals. They’re letting sand in, which is not good,” said Matt Preedy, deputy Highway 99 administrator for the state Department of Transportation (DOT). “Either you’ve got gaps somewhere, or you’ve got cracks in the seals.”
http://seattletimes.com/html/l...
Basically, our water front soil make up is not ideal. Much of the Seattle water front is fill dirt from various late 19th century and early 20th century projects around Seattle. Much of the path Bertha is taking underground is lined with caissons to keep the liquid dirt at bay.
What could possibly go wrong?
Steel pipe or drill rod?
are doing everything they can to screw Seattle. They hate us, and they want us to suffer with horrific traffic by making every project ridiculously expensive. For example, they made our light rail cost over $5 billion. With the few people that ride it each day because they wouldn't let us put it in places that make sense, we could have given every daily rider $166,000 each and come-out cheaper. With this project, they wouldn't allow it to be put in a sensible location so there are going to be fewer drivers using it than the tunnel it replaces. Also, they're going to charge so much that only wealthy people can afford to use it so that us normal people are going to be stuck with surface streets. This is the same tactic they took with the 520 bridge. It is one of two ways into the city from the east, and the Republicans closed it to minorities and the poor.
I sense an opportunity here. Maybe they are interested in "pipe insurance" ? It would be a shame if this happened again to this nice drill.
>"During an effort to drill a viaduct beneath downtown Seattle"
Viaduct? How is digging/drilling a tunnel a viaduct? "A viaduct is a bridge composed of several small spans for crossing a valley or a gorge." http://en.wikipedia.org/wiki/V... You cannot drill a viaduct.
They are digging a TUNNEL under Seattle for a car highway as an alternative to an old, damaged viaduct.
http://www.nytimes.com/2013/12...
Plasma digging robot trapped by ring of concrete pillars under Seattle.
Whether or not Mitsubishi fucked up their cutter head bearing design, or Seattle Tunnel Partners forgot to read the documents that described the exact location of the previous exploratory bore pipe, regardless of if it's even possible to sucessfully extract the cutter head without sinking the current viaduct with all the additional excavation and ground water pumping, this virtual video flythrough from four years ago is my favorite thing to come out of the project.
And if you enjoy crappy flash web cam software, you can watch the current progress on the cutter head replacement shaft here.
So who gets to pay this extra $125 million? Does the contractor company have insurance -- as a contractor who works on your house would have to cover his/her accidents? Or is the bill falling to the tax payers, like when the project goes over-budget for not-so-specific reasons?
World's largest *unclassified* tunnel boring machine.
...Must be having to sell boring machines. I would try to save the situation by going humorous, with an ad series starring Ben Stein.
Most of these TBMs are left in place in an isolation tunnel to rust away once they've finished a job. Why not just get another TBM and scrap this one? It seems like they're going through a lot of work when the TBM is probably only worth 20 to 40 million to fix it.
Harrison's Postulate - "For every action there is an equal and opposite criticism"
Well then, your mom drives a tunnel-boring machine that is not designed to back up and is so fragile that running into a buried pipe breaks it.
Or then, it's your mom who designed one like that.
There, I hope I've made your day.
Right into the wallet of Seattle and Washington residents.
What a boondoggle. And this is literally just the beginning.
So why do they have to drill a whole new vertical shaft to extract the thing? Why can't they just pull it out of the tunnel it drilled? Is this complication something to do with it being "Earth Pressure Balance" machine?
I really found the NYT article to be poorly written and useless on the technical side. It was "gee whiz this is big and expensive" without even the briefest outline as to why the rescue operation works the way it does...
By "Republicans that rule this city" do you mean the City Council, or do you mean Ed Murray, the Mayor? Perhaps you mean the overall populace with its highly one-sided voting record?
Browsing at +1 - no ACs, I ignore their posts. So refreshing!
I feel like I'm reading a porn description.
Can't make your shit out of tungsten so when you hit a teensy 8-inch pipe you don't fuck the drill head up?
They should be asking for a refund on their drill head. I've blown apart 8-inch pipes with 10 inch coring bits and did NOTHING to the bit, which itself was about 1/8th the thickness of the pipes inner walls.
Mohs hardness scale, do you even, motherfuckers?
Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
until someone hits a gas pocket and we're *all* screwed.
Yo mama is so fat, than when she's bored the bore dies.
It seems plausible that dismantling it from behind and assembling a new one in place would have cost more than $45 million (plus $80 million for the new TBM).
At first I wondered why they were going to sink a shaft and tunnel into it with the degraded-but-working machine. Why couldn't they just expand the tunnel behind the machine using less automated digging methods, then back the machine up into the room to get access to the front of the machine to repair it?
Then I looked a little deeper and discovered that they're below the water table, essentially tunnelling through mud-and-rocks under several atmospheres of pressure, and the machine is what is holding back a mudslide, followed by Puget Sound and the Pacific Ocean, and preventing the creation of a big sinkhole under whatever is above them in downtown Seattle.
OK. Sinking a caisson just ahead of them and drilling into it with the gradually failing machine now looks like the cheapest approach.
Bantam Dominique roosters crow a four-note song. Once you've heard it as "Happy BIRTHday" you can't NOT hear it that way