×
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

Circular Foundation
2

Circular Foundation

Circular Foundation

(OP)
I have to design several circular foundations. Does anyone know of either software which will do these or a standard method.

RE: Circular Foundation

2
A little more information is appropriate.  Is this a ring foundation or a flat, cicular slab?  What is the slab/ring supporting?  It may be a simple task of evaluating the stress induced by the supported load and looking up a value in Roark's Formulas for Stress and Strain.  If, on the other hand, you're looking for the stress in the soil I believe there are several texts on soil mechanics which deal with circular foundations (Bousinessq Method).  If not, a text on elastcity will be helpful - check out Prandtl's stress.

RE: Circular Foundation

(OP)
Hi Qshake, This is a circular pad foundation for a 40m high lighting mast, with large overturning moment, shear and a small axial load. Any help would be appreciated but in the meantime will check out Bousinessq. Must find those old collage notes!!!

RE: Circular Foundation

A quick look into Bowles Foundation Analysis and Design yields the following empirical procedures: Chu and Afandi (1966) "Analysis of Circular and Annular Slabs for Chimney Foundations" - Journal ACI vol 63 no 12 Dec. pp 1425-1446 and Smith and Zar (1964) "Chimney Foundations" Journal ACI vol 61 no 6 June pp673-700.  

Again, if you're looking to designing the actual slab I would also look into Roarks.  There are stress formulas for just about every imaginable configuration.

Good Luck.

RE: Circular Foundation

Why are you doing a circular foundation? A circle is an efficient shape for keeping as much material close to the center as possible but in the case of a cantilever mast foundation you want the opposite. It can be much more efficient to use a cruciform foundation or I suppose the most efficient would be a Y shaped foundation. There was some discussion on a footing for a telecommunications tower that I posted a question on a while back on this forum and you might like to look that up.

Carl Bauer
www.bauerconsultbotswana.com

RE: Circular Foundation

(OP)
Qshake

Thanks for the tip. got the ACI documents (eventually - because our Admin staff wouldn't open the post as it came from America and waited until I returned from the States) and they contained just what I was looking for. Certainly will make life easier.

RE: Circular Foundation

I need to review all methods of estimating the settlement under a thin circular foundation on compressible soil so as to compare the results with a more structural approach. I also need to find more info on the methods of estimating the stresses and moments in the foundation. Can anyone suggest?

RE: Circular Foundation

A good (in spanish) reference is

Geotecnia y Cimientos II 2ª edición
Mecanica del suelo y de las rocas
Jiménez Salas, Justo Alpañes, Serrano
Editorial Rueda
Madrid

For Boussinesq checks of soil you have free worksheets in the collaboratory of Mathsoft, civil engineering folder.

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