One thing I was curious about, they don’t spell it out in the video. After the holes were bored for the long concrete rods, they inserted steel sleeves, which they referred to as temporary. I can only guess they were taken out while the concrete was still wet. One would think that would yield a finished product that would have more friction, which is why those things are there - so that they resist movement and anchor the foundation in place.

But speaking of friction, damn, pulling those things out must take a lot of torque. That’s the kind of stuff that would keep me awake at night. Suppose you’re trying to pull the first one out, and it just will not budge. Meanwhile, the concrete is setting up. I’ve had experience of stuff snapping way down in the middle of a hole, pretty much impossible to extract at that point.

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