×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Tank Wall Analysis

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

Equivalent Fluid Pressure of a granular substance depend on two variable; the unit weight (pcf) and the angle of repose (deg.).

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.

www.SlideRuleEra.net idea
www.VacuumTubeEra.net r2d2

RE: Tank Wall Analysis

A couple of years ago, I went through a short course on flow of solids in bins and hoppers. One lesson from that is that if you actually want numbers that have much meaning, you have to test your actual product being stored, as opposed to fetching up a handbook value for the properties.

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.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources