×
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

Residential spread footings rebar

Residential spread footings rebar

Residential spread footings rebar

(OP)
I have to add 2 spread footings to the center of my house, one to hold 9,000 lbs and the other 23,000 lbs.  I have a spread footings design using a rebar size I can't get, so I am looking for advice on how to do the footings using 1/2" diameter rebar.

The soil capacity is 3000 psf.  The footing for 9000 lbs will be 2'x 2' and the footing for 23,000 lbs will be 3' x 3'.   Both would be 1' thick.  What would you recommend for spacing for 1/2" rebar?

Thanks

RE: Residential spread footings rebar

Most interior footings like that end up with 1/2" rebar on a 12" grid.  This is usually very conservative.

RE: Residential spread footings rebar

RustyTools,

What was the rebar size and spacing in the design that you have?  With that information, it would be relatively easy to come up with an equivilant design.

RE: Residential spread footings rebar

The 2' X 2' footing works unreinforced.  The 3' X 3' footing works with (4) #4 bars each way.

DaveAtkins

RE: Residential spread footings rebar

(OP)
The original design was #5 rebar 12"O.C.  That was done by rule of thumb, not by calculation.  The 3000 psf is based on coarse, granular sand and that the builder built the rest of the neighborhood based on that

RE: Residential spread footings rebar

To get the same area per unit width of footing the 0.5 inch (#4) bars need to be installed every ~7.5 inches.  Since the original design was based on "rule of thumb" this is probably more than you need, however, in this case more is better.

RE: Residential spread footings rebar

Any soil problems with using a 2'x2' square footing?

RE: Residential spread footings rebar

That depends on the type of soil, magnitude of the load, and the tolorance of the structure for settlement.

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