Assistance with foundation specifications for industrial machine.
Assistance with foundation specifications for industrial machine.
(OP)
Machine is approx 60K lbs. Layout drawings are somewhat vague and our PE does not do this work commonly.
Here are the parameters I have for now.
Min soil bearing load 3000lb/sf
Min concrete strength - 3000psi
Min foundation stiffness - 5 x 10^6 lb/in
Mod of elas E = 2 x 10^6
I realize the footprint will play into this. Just need a little guidance and general advice.
Here are the parameters I have for now.
Min soil bearing load 3000lb/sf
Min concrete strength - 3000psi
Min foundation stiffness - 5 x 10^6 lb/in
Mod of elas E = 2 x 10^6
I realize the footprint will play into this. Just need a little guidance and general advice.





RE: Assistance with foundation specifications for industrial machine.
At the very least you need to know the operating frequency of the equipment and the unbalanced forces. My belief is that this will fall outside the "light equipment" range where the foundation design is very easy (maximum of 6 kips or so in weight and 200 hp or so). If so, (and assuming your equipment is truly dynamic in nature), you may want to hire a different PE who specializes in this type of foundation design.
RE: Assistance with foundation specifications for industrial machine.
The operating frequency is unknown at this time and not quite sure how we would determine that. It is indeed a dynamic load as a machining tool.
I have examined the minimum recommended subgrade specs at only 3000psf/in or 21pci That seems very low IMO.
I am gathering data and not the one who will run the calcs but I want to opportunity to learn from this experience. We might consult a local geotech with our data but would rather run the calcs and see what we determine first.
RE: Assistance with foundation specifications for industrial machine.
http://www.slideruleera.net/foundations.html
www.SlideRuleEra.net
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RE: Assistance with foundation specifications for industrial machine.
RE: Assistance with foundation specifications for industrial machine.
I am in contact with the OEM now to determine why there is little detail on this.
RE: Assistance with foundation specifications for industrial machine.
Good Luck.
RE: Assistance with foundation specifications for industrial machine.
Your interest in learning something new is admirable, but this a significant enough problem, and a rather specialized area of practice, that you might learn best, quickest, and by doing the least damage, if you study the results of someone who really knows what he is doing on this problem. The operation/performance of your expensive equipment, the productivity of your shop and the quality of your finished product have something to do with the foundation under your machine, and it should certainly not be jumping/bouncing/vibrating/flexing around during operation. If your P.E. doesn’t commonly do this kind of work, a nice way of saying he doesn’t want to chance tackling this found. design problem because he doesn’t know how, not a disgraceful admission; you are a brave (maybe foolish) fellow to assume you will do it then. JoshPlum’s advice and admonitions are right on the money, you might do well to heed them.
RE: Assistance with foundation specifications for industrial machine.
HOWEVER, I finally got a print of the foundation specs!!! They call for 16" of crete with specific rebar placement and such, all we need! However, they are creating a full isolation pad and we now realize what is happening. They want to create a stiff, isolated pad with enough damping for the machine so that any neighboring machines will not affect it. However, the OEM has to make assumptions in shops and the only way to fully protect it is an isolation pad.
However, this shop does not have anything around that would affect the machine to a large enough degree that we would ever see it! I think we can follow the OEM recommendations on the pad but I am resistance on making it isolated. I would rather bar this with the rest of the floor to add damping.
We are still just discussing it and I am sure few here would even consider doing anything except precisely what the OEM recommends but..... has anyone done machine foundations like this? I know of several of these machines that were literally just installed on 12" floors and run great!
RE: Assistance with foundation specifications for industrial machine.
RE: Assistance with foundation specifications for industrial machine.
EIT
www.HowToEngineer.com
RE: Assistance with foundation specifications for industrial machine.
RE: Assistance with foundation specifications for industrial machine.