Tank Wall Analysis
Tank Wall Analysis
(OP)
I am working on analyzing the framing for the wall of a tank that holds 300 tons of roof granule. I am struggling with determining the load to apply to represent the granule when the tank is full. Does anyone have a recommendation for an equivalent fluid pressure that could be used? I have seen an EFP around 25 psf/ft used for gravel backfill, but the granule is loose and much smaller. I appreciate any suggestions.






RE: Tank Wall Analysis
Unless you have more appropriate info, I found this data: Roofing Granules Physical Properties
The "bulk density" is given as 90 to 96 pcf.
Published angle of repose for "dry gravel" is about 37o.
For "clean, dry sand", about 34o.
Suggest staying conservative and calculating EFP using 96 pcf and 34o.
Note: Looking at a table of angle or repose for various granular materials, 34o is the lowest (most conservative) value I saw.
EFP = 96 pcf x tan2 (45o - 1/2 x 34o) = 27.1 pcf
Say, 28pcf
Not much different than the value you found, but at least 28 pcf is based (partially) on the properties for roofing granules.
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RE: Tank Wall Analysis
If the structure is small enough, treating the product as liquid (using the actual density) for the outward pressure and treating it as plugged (product entirely supported by the shell) for vertical shear loads will simplify the design considerably.
RE: Tank Wall Analysis
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