Concrete Foundation 9

[hnickelson]

I am planning to install a 44,000 lb hydraulic press with a 150-200 ton press capacity. How do I go about deciding what foundation I should use? It is designed to be floor mounted, so I'm not sure if I need to pour a concrete foundation or not.

Any Help Please

 

[gandersen]

hnickleson:

I have seen presses like what you are describing floor mounted on isolated footings. Depending upon the soil conditions, the press could be on a monolitic block or could be on a structural slab supported by deep foundation elements.

You should really contact a local geotechnical engineer for a specific foundation recommendation.

Good Luck

 

[witchdoc]

How are you feeding the press? Can you tolerate some settlement? This is not a big press--and hydraulics typically don't have a lot of impact load. Have you asked the press manufacturer for a standard footing detail?

 

[jimbo2]

The first thing I would ask is do you have any geotechnical data describing the shallow subsurface soil and groundwater conditions? What are the compressive/shear properties of the soils? Any foundation design must start with this type of info. Also, not being familiar with the this equipment, what is the geometry of the base of the press? Will you have any concentrated loading of the foundation?

I think gandersen is giving the proper advice - work with a local geotech to help get your answer.

 

[roeng]

Hello,

I suppose you know all loads you have to deal in order to transfer them to the foundation/floor, whatever. Check the structural element, and the soil. However I suppose you won't find sufficient structural capacity unless it was provided from the beginning. Check also for applicable codes for dynamic loads on foundation (I suppose for this kind of engines they are special requirements). Usually I'll think at a minimum 30cm RC pad under the press and, sometimes, to isolate the pad from the existing floor. So I suppose that's why this machine has floor mounted supports.
About geotechnical engineer, contact one if affordable or is yours friend.

Best wishes!

 

[BigH]

. . . if affordable?????? Geotechs are probably the "most" affordable of the lot (more so that structurals ! ). - Look at that guy who does house investigations for US$60 each!! (see some other thread!)

First: I doubt the floor of the building, unless it envisaged such a situation is designed for structural loading of this type. I would opine that it be best to cut the slab and install a separate foundation for the press. This assumes that you will have a geotech looking out for your best interests and that the detailed substrate conditions are determined along with the groundwater levels as appropriate.

Second: Even if you could show that the floor would likely be okay - I still believe it prudent to be safer than not.

Keep us advised.

 

[Focht3]

[blue]BigH[/blue] got it right. Don't trust the existing floor unless you know that the slab was designed with this particular load in mind...



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[DDS1]

I can't add much that hasn't been touched upon but here goes. First, it is fair to say that the floor that exists wasn't designed to hold this press (unless you are replacing an existing one) because it probably wasnt a conceived load at the time the floor was designed. And in line with our geotech friends, any slab, or independent foundation is only as good as the bearing surface in which it bears. If you contact a consultant engineer with your application you will end up with an isolated independent foundation that resets on soils of known allowable soil bearing capacity. Unfortunatley in practice I have seen people sit substantial loads on floor slabs that were not intended for these loads. It only shows that the world is filled with many lucky people. As to my personal opinion as to geotech affordability, I don't know that a person can "afford" not to aquire their services unless you have dont similar work in the same general area and have a geotechnical report for the soil conditions and their allowable soil bearing capacity in that surrounding area. Then dont forget that these reports a representative of what is in the area and only after you dig do you confirm or not confirm what you thought you had for soils accordign to the geotech report. I'll stop rattling now. A person could go on forever.

DDS1

 

[Focht3]

Yup - I've been known to ramble from time to time. Imagine how long-winded I might be if I could really type!






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[Grouser]

hnickelson

As a further piece of advice, shop around for a geotech consultant who has experience/expertise in machine foundations.

Are there other nearby operations in the factory that are susceptible to vibrations from the press you're installing? The geotech consultant needs to know this info to properly design the foundation system to prevent/minimize the vibration affects. Does the press manufacturer give a maximum load to the foundation by the press when it is operating?

Good luck.

 

[Focht3]

Along the lines that [blue]Grouser[/blue] raises:[ol][li]The new foundation should be separated from the existing floor slab. A good elastomeric sealant should be applied to the expansion joint to keep it waterproofed. Don't use a rigid grout; you will only cause problems - and will have to replace it with an elastomeric.[li]A broad, shallow foundation is gemerally better than a narrow, deep foundation with respect to vibration damping. This "geometric damping" is independent of the soil type or properties.[li]Be aware that the allowable deflections from reciprocating equipment need to be kept quite small since their cumulative effects can cause problems. These deflection tolerances are much smaller than the normal geotechnical tolerances for static settlement.[/ol]Let us know what you elect to do -



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