Punching shear (?) question.

[kingnero]

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...

 

[ztengguy]

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?

 

[kingnero]

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.

 

[TXStructural]

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.

 

[kingnero]

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...