×
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

Mat foundation, what "strip width" to design for

Mat foundation, what "strip width" to design for

Mat foundation, what "strip width" to design for

(OP)
A four column footing, columns space 20' each way, supported on a 26' square footing.  i.e. edge distance outside columns is 3'-0".

Footing approx. 2'-6" thick, all pedestals are 2'-0" square.

To design for shear & moment by strips, I read in an old textbook that rule of thumb for strip width is Pedestal + 3d, which gives strip 2' + 3(2'-2") = 8'-6" wide.

Sounds reasonable, but looking for any possible references to confirm.

 

RE: Mat foundation, what "strip width" to design for

I would just duplicate the outside width and use 6 foot strips between/beyond columns, (including the diagonals).

RE: Mat foundation, what "strip width" to design for

I would either design this as a two way slab, using the ACI rules, or analyze it with a finite element computer program.

DaveAtkins

RE: Mat foundation, what "strip width" to design for

Concentrate reinforcing under the columns within a band as specified by Code.

HTH

VOD

RE: Mat foundation, what "strip width" to design for

You could take a six foot wide strip centered on each of the four columns.  The 14'x14' slab in the middle could be reduced in thickness in order to save material (your option).  It would be designed as a two way slab spanning between all four beams.

Any reasonable assumption would be okay.



 

Best regards,

BA

RE: Mat foundation, what "strip width" to design for

(OP)
Thankyou to all for your input.

As I did not have access to a F.E. program last week, I designed 6' wide strips along all four column lines, and reduced the reinforcing somewhat for the 14x14 interior.

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