×
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 footing design

circular footing design

circular footing design

(OP)
Any guideline on design of circular spread footing

RE: circular footing design

I guess they would rather drill them than dig them?  If you are designing for gravity only, reinforce them like they were rectangular (two mats) and design worst case for 1' section.

RE: circular footing design

I don't know how big your footing is, but I would probably want an orthogonal rebar layout versus a radial layout.  With an orthogonal layout I would inscribe a square and then design as a rectangular footing.  

RE: circular footing design

What are the plan dimensions of the circular foundation.  They are commonly used for single pedestal elevated water tanks.

Joe Tank

RE: circular footing design

(OP)
8 feet dia to 32 feet dia tanks and high up to 50 feet. So footing can be 0ne or two feet larger. No pedestal. Tanks are directly mechanically anchored to circular slab on grade.

RE: circular footing design

For the 8 ft diameter tanks I would expect to see a square footing, not round.  Forming and rebar fab would be less for a square footing.  The square would probably be cheaper for tanks up to about 20 to 25 feet in diameter.  After that I would expect a hex or octagonal shape.  Again forming costs would be lower.

Joe Tank

RE: circular footing design

(OP)
Any design aid, freeware, spread sheet to design hex or octagonal shape footing

RE: circular footing design

Typically, a circular tank footing would have rebar laid out in a square grid.  Sum moments and shears about a straight cross section to design; also check shear on circular sections outside the tank.  With no seismic or wind moment, the controlling section is normally at the slab center.  With large moments, the controlling section can be nearer the toe of the slab.  Most economical shape can vary depending on the contractor.  See ACI-318 App. D, latest revision, for anchor bolt design.  I've not seen any design aids online.

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