×
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

4 tanks - 1 mat foundation?

4 tanks - 1 mat foundation?

4 tanks - 1 mat foundation?

(OP)
I have 4 tanks. Tanks will be full of fluid, size is 32' high and 15.5' diameter.
I'm taking over this design from another engineer.
He has 1 mat foundation for all tanks, mat size is 80' x 24'.
I'm concerned if this will cause issues with differential settlement if one or few tanks are either empty or full.
Shouldn't this be addressed in Geotech report.
Geotech report only suggests use drilled pier for large vertical loads with a bunch of formulas for drilled pier axial capacity.
I don't even know why the original design is only on mat foundation and not on deep foundation but that guy is gone now so I can't ask him.

RE: 4 tanks - 1 mat foundation?

Sounds like he ignored the geotechnical report. Likely if a single mat had been feasible, the geotechnical engineer would have noted that. Considering he/she recommended drilled piers for the tanks, there are likely soil conditions below that would be detrimental to a mat foundation. You might consider a pile supported mat if you're concerned about differential settlement.

A talk with the geotech might clear up some things.

RE: 4 tanks - 1 mat foundation?

The mat could have been part of a containment system for the tanks.
If one tank is empty and others full- that would not generally be addressed in the soils report, other than to give you a subgrade modulus or something like that; that would be assumed to be elastic deflection, not differential settlement.

RE: 4 tanks - 1 mat foundation?

I have done several mat foundations with multiple tanks (90' tall- 12' diameter) on them and haven't had any differential issues. We have had really good allowable bearing pressures (5 ksf+) though, so that helps. The geotech has always been really instrumental in what we do so I second Ron's comment. One item to add is a discussion with the owner to determine what their operational loading will be. My projects have been in the dairy industry so the fluid levels are really dynamic and there isn't really the "time" for settlement to occur unless a tank goes offline.

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