Sounds like a silly question maybe, but it’s seriously meant. We have cast vaults here, both on the entrance floor and the upper floor. The construction itself is that a ceiling is cast, then there are some kind of indeterminate fill masses, and then another layer of concrete, which then becomes the floor. It's far from even, with dips and quite a bit of slope in some places. But there are no visible cracks anywhere. Mostly curious if it was sloppy from the beginning or if it can settle that way without cracks over 50 years? When I think about it, I tend to believe the latter since I've seen the same at work.
I have seen many concrete foundations under large silos that have buckled under the weight load from the silos, but the concrete slab has not cracked. It looks a bit odd because the concrete foundations have buckled quite significantly.
But as for an arch that buckles, I've never seen it, but I have definitely heard of private customers who have skimped on the reinforcement (5 mm mesh instead of 10 mm mesh) and the following year they can't open or close the interior doors on the lower floor and the walls buckle under the weight.
When the insurance company sees that the vault is only reinforced with a 5 mm mesh, they drop the case.
But as for an arch that buckles, I've never seen it, but I have definitely heard of private customers who have skimped on the reinforcement (5 mm mesh instead of 10 mm mesh) and the following year they can't open or close the interior doors on the lower floor and the walls buckle under the weight.
When the insurance company sees that the vault is only reinforced with a 5 mm mesh, they drop the case.