×
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

Janssens Formula and Unit Weight of Grain

Janssens Formula and Unit Weight of Grain

Janssens Formula and Unit Weight of Grain

(OP)
I am looking for a book that has a good description of Janssens Formula for circulat tanks.  I am hoping for a good explanation of theory as well as application.  The latter being most important.  The method we use has different variables than the one a structural engineer uses.  Our values differ by 50%.

Also, can anyone give me a good rundown on the unit weights of grain (compacted and uncompacted)?  Would like pounds per bushel as well as pounds per cubic foot.  Metric units is fine.  Mostly grain bins and silos we deal with use wheat, corn, beans, sugar, sunflowers, and flax.  We base our calculations on wheat.  I understand that wheat is the heaviest grain we have.  We use 50pcf for wheat, the structural engineer is using 57 pcf, a web search shows values ranging from 46 to 50 pcf for wheat.

I just want to get a handle on this, grain bins have been dramatically increasing in size.  There is becoming a problem with soil capacity and settlement.

Thanks in advance for the assistance.

RE: Janssens Formula and Unit Weight of Grain

(OP)
I just found out the reason for the difference.  Apparently the structural engineer is using a correction factor.  This correction changes Janssens results to correlate with the results of another method.

I would like to know the what the other method is, and how to use it, if there are any other ideas as to what it is.  I will try to find out who this other engineer is and get the details.

Thanks.

RE: Janssens Formula and Unit Weight of Grain

wheat 750 to 760 kg/m3
oats 410 to 540 kg/m3
corn 670 kg/m3
barley 600 to 700 kg/m3
rye 685 to 790 kg/m3

hope it still helps !

RE: Janssens Formula and Unit Weight of Grain

I have a copy of a translation of the original Janssen Paper 'Experiments in Corn Pressure in Silo Cells', Aug 31st 1895, including original fig's.  The experiments he performed are great, and the basic formula still in use today!  

RE: Janssens Formula and Unit Weight of Grain

Perhaps you can request SlideRuleEra to put on his website?  He is putting on a lot of the "old" stuff. SRE??

RE: Janssens Formula and Unit Weight of Grain

Jim - thanks to see you back!! Terima kasih for the link!

RE: Janssens Formula and Unit Weight of Grain

jheidt2543,
Perfect. I often print articles off the internet and so long as they have a reference otherwise haven't a clue where i got them.  This paper is an essential for those of us designing bins and silos, it is infact the starting point despite the fact that Janssen took advantage of others previous work in this area at the time.

RE: Janssens Formula and Unit Weight of Grain

connect2 when I download papers off the net, I usually (try almost always) to copy the URL to a "Note" comment that I put on the efile pdf copy.  This way you can always find the URL again.  Just a thought.

RE: Janssens Formula and Unit Weight of Grain

(OP)
Thank you jheidt2543 for the link.  Very interesting paper, I like reading the theory behind the formulas.  Thanks for the tip BigH.

RE: Janssens Formula and Unit Weight of Grain

BigH, good idea.  I have much to learn about electronic filing and files.

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