Seattle Tunnel Project: World-Record Drill

Discussion in 'Architecture & Engineering' started by Tiassa, Nov 24, 2012.

  1. Tiassa Let us not launch the boat ... Staff Member

    Messages:
    34,694
    A Note on Seattle Governance

    Did you know that being the Mayor of Seattle is a dead-end job? It is said that no Mayor of Seattle has ever gone on to statewide elected office; in 1969, Mayor d'Orma Braman took an appointment to Nixon's Department of Transportation, which might be the highest any of them ever managed.

    It will take some digging to get the real story on that old claim, but digging is also the key to understanding the latest example of why the job is a political career killer.

    To bring you up to date on the Dumbassed Dig, it is enough to simply say that Bertha remains broken↑, officials are still arguing not just over whether and how to fix the drill, but are also trying to consider the dangers of trying to either extract the drill or repair it in place versus the financial loss of simply leaving her where she is.

    Nobody says they'll do that, as far as I know. But there is also widespread cynicism by which it's also what many expect.

    Sydney Brownstone↱ of The Stranger tries to explain the bureaucratic situation:

    Pit bad? No, pit good.

    That about sums up much of the two-hour Washington State Department of Transportation briefing in front of the city council yesterday, in which council members peppered the state with questions about a strongly worded letter the Seattle Department of Transportation and Seattle Public Utilities fired off last week. In it, city officials expressed alarm over the fact that language about "risk of a catastrophic failure" disappeared from a draft report by rescue pit engineers with no explanation.

    Shouldn't city agencies have been contacted about concerns related to a potential "catastrophic failure"? Why weren't they? And why did the language change? Did "risk of a catastrophic failure" refer to the pit's impact on the viaduct? Did the Washington State Department of Transportation tell the contractor to stop digging in mid-December because of this risk?

    WSDOT's Todd Trepanier hardly disguised his irritation with the letter and the city council's subsequent line of questioning. "There never has been, and there is currently not, any risk of failure," he said. "That is a gross mischaracterization of that word ‘catastrophic' in the report."

    Earlier, Trepanier stressed WSDOT's disappointment with SDOT's actions: "To send this letter, to provide it to the press before we were able to respond, is not in keeping with the partnership we established with the city, the county, and the port, and needlessly escalates public fear," he said.

    According to the state, Seattle transportation officials went into the tunnel project's shared database, cherry-picked the report, then cherry-picked the language in it. The draft report listed action items needed in order to keep excavating. WSDOT says the language that changed dealt with stabilizing soil between support columns around the hole. When the report's authors—rescue pit engineers—noticed that the grouting between those columns ("piles") had not been fully completed, they issued a report warning about "repair as we go" excavation and the potential for "catastrophic failure."

    Which still didn't make a ton of sense to most other people in the room ....

    And government being what it is, local government being what it is, and Seattle government being Seattle government, what we come to is an overpriced bureaucratic circle of indecency:

    So, what did we learn?

    - SDOT still hasn't gotten a full explanation for the language changes.

    - WSDOT staff saw those changes, or at least they signed off on them.

    - We still don't really know why "risk of a catastrophic failure" was deleted.

    - The rescue pit is roughly 20 feet away from the nearest bent (a viaduct support structure), and Council Member O'Brien is pretty worried about that.

    - WSDOT is pissed that SDOT went through its drawers.

    - The city council is trying to make peace between the two levels of government.

    - SDOT has a mid- to long-term contingency plan for shuttering the viaduct. It's also hired independent engineers, CH2M Hill, to get another opinion on whether dewatering and Bertha's rescue threaten the aging structure.

    As to actually dealing with the problem?

    I bet now the council members who have been around long enough to remember wish they'd built the fucking monorail the first three times they were told to do so. Because when it comes to actually dealing with the Dig and Bertha, we're past the point where people argue over which of the obvious things that need to be done should be done and have moved on to interbureau political warfare.

    Okay, that's a gross mischaracterization of "warfare". It would be more accurate to say the city and state Departments of Transportation are having a slappy fight while dead Bertha waits dreaming.
    ____________________

    Notes:

    Brownstone, Sydney. "What We Learned at Yesterday's City vs. State Fight over Bertha's Rescue Pit". Slog. 13 January 2015. Slog.TheStranger.com. 13 January 2015. http://slog.thestranger.com/slog/ar...s-city-vs-state-fight-over-berthas-rescue-pit
     
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  3. Tiassa Let us not launch the boat ... Staff Member

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    Bertha's Still Dead

    Ah, the "Friday News Dump". Sydney Brownstone of The Stranger notes a FND trend emerging in Seattle:

    Are these Friday settlement updates going to become a regular thing?

    We hope not, but then again, WSDOT has released some of its most memorable updates on Fridays. Take, for example, finding the steel pipe (reported on Friday, January 3, 2014). Or take the announcement of an inch of ground settlement around the Pioneer Square rescue pit (on Friday, December 5). And hey, if WSDOT is committed to burying bad news on Fridays, we can stay committed to making noise about it on the following Mondays.

    This most recent Friday update came at the very bottom of the post titled "Safety at the Forefront," below a section dedicated to a time-lapse video of the construction of a red gantry crane. The crane's awesomeness noted, WSDOT then went on to note that it had observed “minor viaduct settlement.” Over the span of 500 feet south of Main Street, the viaduct has sunk up to a quarter of an inch in the last month.

    “The viaduct remains vulnerable to earthquakes, but it is still safe for everyday use,” the post read. “If we had any reason to believe the structure was unsafe, we would not hesitate to close it.”

    I followed up to ask about the maximum amount of settlement allowed on that section of the viaduct, but WSDOT spokesperson Laura Newborn said that the “contract has many points of measurement, with different amounts allowed on different parts of the viaduct.” Overall, the contract specifies maximum viaduct bent settlements between a half an inch to two inches at different bents. (Bents are viaduct support structures along the length of the route.)

    WSDOT added that the viaduct has been sinking for quite some time, and they expect it to continue to sink until it’s taken apart. In the meantime, Seattle Tunnel Partners will try to restart Bertha sometime this week so the machine can try to carve through 20 feet of concrete.

    Meanwhile, did you know there is already a museum for Bertha? As Ms. Brownstone noted a bit over a week ago:

    The only thing that's left between Bertha, the tunnel boring machine that's been stuck for a year below Pioneer Square, and the sweet, sweet freedom of release is 20 feet of concrete. On Thursday night, Washington State Department of Transportation deputy program administrator Matt Preedy explained how, exactly, the contractor plans to get Bertha into the bottom of a newly finished, 120-foot-deep, concrete-lined pit where workers will then tug her teeth and damaged front-end into the light.

    Preedy told a room of 20 or so people assembled at Milepost 31, the small Pioneer Square museum dedicated to the tunnel project, that even in her damaged state Bertha should be able to roar back to life and "make it all the way through" the 20 feet of concrete lining the wall of the rescue pit. "The contractor is confident," Preedy said, "but they do have a contingency plan if she does not,"

    Keep in mind, though, that Bertha is broken. And how broken? Her seal array, the part of the machine that separates the gunk in the cutterhead from the gears behind it, is "basically 100 percent damaged," Preedy said.

    So what's that Plan B for getting Bertha past 20 feet of concrete if she can't chew through it? Preedy explained that the contractor would lower an excavator to the bottom of the pit, build a platform for it, and mount a "giant jackhammer" to the end.

    "They would jackhammer out a Bertha-sized hole, and all the concrete would fall into the shaft, and you’d have to get all the concrete out, which would take time," Preedy told me. "But eventually they would be able to chip a hole back to the front space of the machine and push the machine out."

    This would be funny except ... er ... hey, nobody's died, yet, right?

    So ... right. This can be funny, right?

    Because it's freakin' hilarious. Morbidly so, but still.
    ____________________

    Notes:

    Brownstone, Sydney. "Here's the Bad Tunnel News the State Quietly Released on Friday (In Short, the Viaduct Is Still Sinking)". Slog. 16 February 2015. TheStranger.com. 16 February 2015. http://www.thestranger.com/blogs/sl...ha-news-dump-on-monday-the-viaduct-is-sinking

    —————. "How, Exactly, Are They Going to Get Bertha's Teeth Out of That Pit? WSDOT Explains." Slog. 6 February 2015. TheStranger.com. 16 February 2015. http://www.thestranger.com/slog/arc...-berthas-teeth-out-of-that-pit-wsdot-explains
     
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