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Punching shear (?) question.

Punching shear (?) question.

Punching shear (?) question.

(OP)
I need to install a safe in a friend's house on a metal structure so the safe will sit about 2 ft above floor level.

I wil design the metal structure, but I need to know whether I can put the thing on 4 legs, or if I need to have a square frame at the bottom as well to spread out the load.
Problem is that if I need a frame at the bottom, it'll need to be field welded partly (exisiting pipes and electricity in the way).

Weight is around 600 kg (1300 lbs).

What data should I prepare before consulting an engineer that does this kind of work?
I know the thickness of the slab and the grade of concrete. I do not know what's below. Should I even bother to ask in this case, and go directly to a full frame, with the problems that go with this solution (welding inside ahouse, near piping and electricity)?

If I could put the whole thing on 4 legs, that would make the install mush simpler.


please guide me on how to proceed...

RE: Punching shear (?) question.

My gut (engineering judgement) says you dont need to worry. 325lb point load on a concrete slab isnt really much. It more than likely would be safe to put it there.

What is the thickness of concrete and size of the safe?

RE: Punching shear (?) question.

(OP)
Footprint of the safe is about 20x20 or 20x30 inches, and as high as a normal gun safe. I will check actual data next week.
Slab is poured inside the house (and has nothing to do with foundation of the house), and is 4-5 inches thick. low grade concrete (again, I don't know by heart, but I will get his paperwork of the delivery/payment/installation, and that will mention the class of the concrete). Also, no rebar or fibers.

you're talking point load, legs will be 30x30 or 40x40 mm ( 1 1/4 x 1 1/4 or 1.5 x 1.5 inches) with a square plate of this size welded on. that should also lower the contact pressure.
Thanks already for sharing your opinion.

RE: Punching shear (?) question.

If it is slab on ground, do not worry about it. It is simple enough to use loose plates or lumber under the feet to distribute the load over a larger area (mostly to avoid local, surface damage.) If it is a floor above ground, that is, if it is a slab on structure, you might also be worried about a concentrated load on the structure.

RE: Punching shear (?) question.

(OP)
It is slab on ground, but I do not know the quality of the soil.

Thanks for your replies, it appears I can solve this with some common sense and without having to weld inside the house...

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