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Seattle's Behemoth Boring Machine, Idle Since 2013, Makes Some Progress
After being blocked by an obstruction ("the object") which left it idle just over two years ago, repair work has continued on Bertha, Seattle's enormous tunnel-boring machine. Now, reports KOMO News and The Seattle Times, Bertha is once again ready to work. From The Times' coverage:
Tuesday morning's push of one and a half feet provided Seattle Tunnel Partners (STP) enough space behind Bertha’s drive motors to fasten the next concrete ring at the 1,085-foot mark of the planned 9,270-foot tube. Chris Dixon, STP project manager, is calling this a testing phase. The team is measuring how Bertha responds while rotating through heavy loads of compacted sand. Last week, a fixed steel arm in the front end broke and needed a one-day repair. ... This week’s two-day push would leave the nose of the drill just short of the north edge of the concrete vault, dug in 2014 so STP could reach and lift the 4million-pound front end for repairs. The winning bid from STP called for the tunnel to be completed this month.
Yes. But the path of the tunnel runs through what is essentially an old land fill. So the machine should have been designed to deal with old steam boilers, scrap iron, chunks of concrete/rebar, etc.
Have gnu, will travel.
Rock crumbles, is brittle, and has a low tensile strength even though the compressive strength is high. The sort of steel used for a pipe is none of those things.
See also stuff designed for "soft rock" suddenly hitting Basalt.
Seattle taxpayers are not paying for this project, except insofar as they are taxpayers to the State and the Feds, which are. "Local" funding is a small percentage of the $3 billion project. Further:
1. I-5 is a parking lot. Traffic congestion in Seattle is 5th worse in the nation.
2. The current Alaskan Way Viaduct is an ugly concrete behemoth.
3. The current Alaskan Way Viaduct is going to fall down.
4. The current Alaskan Way Viaduct carries 110,000 vehicles a day.
5. We can all ride bicycles because the city has closed one entire lane of most downtown streets to accommodate it.
How about a moderation of -1 pedantic.
And maybe, just maybe they'll come away with some lessons learned form this kabillion dollar, 0.5mph joyride.
Maybe one of those lessons is "there are risks when you try to save money by pushing the boundaries with new, untested drilling technology".
Meanwhile the tunnels Sound Transit has been recently digging in Seattle, following ho-hum old smaller bore twin-tunnel principles, are going well - they're under budget and ahead of schedule. I am really looking forward to taking light rail to UW in a month or two! No more sitting on a bus that's stuck in traffic gridlock...
#DeleteChrome
In a country who's infrastructure is crumbling; roads, bridges, fresh/waste water systems, electrical grid - failure to fix public works projects IS a threat to our security
The scaremongering about our "crumbling infrastructure" comes mostly from ASCE, construction companies, and politicians trying to get pork for their district. These are all special interest groups with their snout in the trough. There is little evidence that our infrastructure is actually getting worse. On a per capita basis, infrastructure failures such as bridge collapses, are less common than they were a generation ago.