×
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

HELP beam on grade with moment

HELP beam on grade with moment

HELP beam on grade with moment

(OP)
HI

I have a beam on grade to design. I have all soil parameters etc spring stiffness. But I do not have a point load(s) just a moment in the center of the beam. Been checking all my standard text books but I can only find beams on grade with vertical point loads. Mine only has a moment. Do I really have to wheel out my FE structural software package for such an apparently simple problem?

Hope anyone can help
Cheers

RE: HELP beam on grade with moment

Roark's Formulas for Stress and Strain includes beams on elastic foundation with intermediate moment.
Or you could use the solutions for vertical point loads, assume one load up, one load down, a short distance apart to make the moment.

RE: HELP beam on grade with moment

To resolve the moment, you will need to consider the dead load of the grade beam, which can be considered a point load at it's centroid.
Have you considered a short drilled pier? That is more conventional for a sign post foundation.

RE: HELP beam on grade with moment

(OP)
Yes, Roarks, Table 8.6 brilliant, thanks!

RE: HELP beam on grade with moment

If you want to be thorough, after you have applied the Roark equation you'll need to superimpose the effect of your beam's self weight (a totally trivial exercise) and make sure you don't have significant lift-off.

RE: HELP beam on grade with moment

Quote (JStephen)

Or you could use the solutions for vertical point loads, assume one load up, one load down, a short distance apart to make the moment.

It's this one for me. It's a rare, isolated foundation element that warrants FEM - or even beam on elastic -- in my opinion, especially given the uncertainties associated with the input parameters.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

RE: HELP beam on grade with moment

If the self weight of the beam is P, then apply P at eccentricity e from the center of the beam. This should have the same effect as applying a moment M = P.e while simultaneously including the dead weight of the beam.

BA

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