Lateral potato pressure?

[jeffandmike]

We have a client that is interested in building some potato storage facilities. My understanding is that the potatoes are piled in bulk on the concrete floor (apparently up to 19'-0" high in this case) against the exterior walls (also concrete) of the rectangular building. A tie from exterior wall to exterior wall is established at the top of the wall (I believe it's through the roof framing members or through tie rods). Obviously, a retaining wall of sorts is created.

So the question is, what is the active pressure of potatoes? Furthermore, if it could be assumed that the top of the wall is sufficiently restrained, what is the at rest pressure of potatoes?

I was able to look up in an older design manual we have that the bulk density of dried potatoes is 58 lbs/cu ft, although I would assume that the potatoes aren't exactly "dried" when they're first placed in the building (the actual bulk density is probably higher). Of course what I don't know is the angle of internal friction of potatoes.

Any assistance you can provide would be greatly appreciated.

Also, if anyone has any other "gotchas" on facilities such as these, feel free to voice your opinion.

Thanks.

 

[WillisV]

Mutch to my suprise there are actually standards for the lateral pressure of stored potatoes -

The American Society of Agriculture and Biological Engineers publishes ASAE ANSI/ASAE EP446.2 document entitled "Loads Exerted by Irish Potatoes in Shallow Bulk Storage Structures" - See:

http://asae.frymulti.com/abstract.asp?aid=21780&t=2

The following document also has an equation for lateral pressure due to stacked potatos which originates in the ASAE document previously mentioned:

http://asae.frymulti.com/abstract.asp?aid=21780&t=2

It gives the angle of repose at 37 degrees.

 

[WillisV]

errr...2nd link was supposed to be:

http://cigr-ejournal.tamu.edu/submissions/volume8/Invited Overview Eltawill 10May2006.pdf

see pages 10-11

 

[JedClampett]

If you don't design it correctly, make them use it for potato chips instead.

 

[COEngineeer]

Wow.. so it is 2nd order polynomial, good luck trying to find the area and the center of gravity .

 

[rb1957]

19' is higher than the recommended 3-4m

 

[COEngineeer]

19'.. mashed potatoes?

 

[SlideRuleEra]

In addition to the forces from a static pile of potatoes, be sure to consider additional forces that may be applied when the potatoes are being put in place (perhaps falling from a conveyor belt) or taken out of storage (maybe a loader pushing the pile against the wall).

http://www.SlideRuleEra.net

 

[jechols]

An engineer in my office said the material might not behave like a fluid. There might be higher pressures further up the wall than the equivalent fluid pressure method would yield. However, I think all sides have to be confined for the arching effect to take place. Good luck.