Pressures Acting on Grain Silo Discharge Hopper

[Duster475]

Hello all, this is my first post on here:

I looked through some previous threads but I do not believe my question is quite covered by similar topics.

I have been asked to review the loading on a steel pyrimidal hopper in which grain discharges from at the bottom of a square concrete silo. I have dove into ACI 313-97, the commentary of that document, and the information provided by Jenike. What I was intrigued to find was that in ACI 313-97 the initial filling pressure increases with the depth of the hopper, but yet the Jenike information shows the opposite.

As well, one must consider the discharge pressures for mass flow for this particular geometry. The mass flow pressure equations as laid out in ACI 313-97 increase with the depth of the hopper, whereas in the commentary of this document a completely different formula is presented and suggests that the mass flow pressures actually decrease with the depth of the hopper. Jenike also supports this decreasing load with depth of hopper for mass flow.

You seem to get different pressure distributions along the depth of the hopper no matter what method you choose. I was wondering if anyone has encountered these different methods and can shed some light onto what way is most accepted and has been used effectively in their experience.

Thanks,

 

[Splitrings]

You might check out ASABE EP545, "Loads Exerted by Free-Flowing Grain on Shallow Storage Structures". I am not certain it applies to your situation or not.

 

[Duster475]

Thanks for the reply. I am not too sure if it does since it applies to shallow structures but I will check it out!

 

[MiketheEngineer]

A number of Universities with AG depts have papers on such mundane subjects. You might want to call or check them out. Ones that come to mind are MO, IA, NE, KS, etc --- where most of the grain is grown.