SOMA Nature Walk

This is my current favorite piece of construction equipment:

They are using it to dig very narrow, deep holes which they then drop girders in to. The girders are 3' tall and at least 50' long. I gather that these are the support walls that will prevent the whole block from collapsing once they drop the drilling machine in. Since this neighborhood is built on sand piled on top of broken docks and scuttled ships, they presumably have to go pretty deep to hit rock.

But the thing that I think is really great about this is that someone took the time to engineer a die-cut logo into the side wall. Maybe that didn't take much in the CAD program (it doesn't remove that much mass), but still, it suggests that someone actually gave a shit about this big scoop. It could have been bolted on, but instead it goes straight through an inch of steel.

(There are actually two different kinds of scoop pictured here, but the taller, cooler one is hard to shoot.)

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7 Responses:

  1. Stein-Greifer means "stone-claw" in German, too. I'm surprised it's not already an Industrial band name.

  2. Ike says:

    Regarding the logo, that whole sidewall plate may have just been cut with a waterjet. Or laser, or plasma cutter. When you've got a CNC machine that quickly and trivially goes through inch-thick plate steel, every piece of inch-thick plate steel looks like an opportunity for gratuitous logos made out of or removed from that steel.

    Engineering-wise, the holes those letters make might be far enough away from the edges of the plate that they have a literally negligible effect on the performance of the device, but it would be really cool to know whether someone actually finite-element modeled it to make sure, or whether the holes are even deliberate to allow a tiny bit of flex in that area for some reason.

    • Ben Brockert says:

      I would bet laser. Better tolerancing and less cleanup of the edges.

      They definitely did FEA on that, it'd only take an hour or so of work to be sure you weren't doing something dumb.

  3. It get's better: these machines are used to excavate trenches for entire walls that can be used structually or to block water from entering an area. So how do you make sure those trenches, up to 120 feet deep, do not cave in? You fill the cavity with "slurry" which has the same density as the surrounding dirt, but is liquid enough to be pumped around. Once dug, you put in rebar and fill it with concrete, which displaces the slurry. The slurry can be reused elsewhere.

    They're regularly used for "cut and cover" tunnel building; Boston's Big Dig had it's own on-site slurry producing factory, and if I remember correctly, used like a third of all slurry world wide during it's construction.

    • There was an episode[0] of "Build it Bigger" where somebody needed to build a concrete wall in the ocean, so they made a sand island, then used these shovels to dig a slurry "wall" in the sand, poured the concrete, and then sucked away the sandbar. (0.o)

      [0] ep.810: Port of Rotterdam

    • jwz says:

      I think that's probably what they were doing here, too. There was a lot of pumping going on, which sounds like the slurry.

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