×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Contact US

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!

*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

What is the efficient foundation system for elevated tanks?
4

What is the efficient foundation system for elevated tanks?

What is the efficient foundation system for elevated tanks?

(OP)
Pals


This one always makes me uncomfortable and I can use your experience.

Elevated tanks supported on 4 steel braced legs, will usually have 3units of compression on 1 pair of legs and 1 unit of tension on the other pair when wind or quake works on it.

Say +75ton on each of the compressed pair and -25ton on each of the other


spaced say 25ft apart, and taking any two legs at a time:
with medium level bearing capacity, say sandy clay

1) combined footing wont usually work

2)my favorite 2 footings with a strap beam wont usually work



and I am usually left to join all 4 legs with a mat(Piles are expensive in remote areas where these structures are built)

and if it turns out that one leg can not join the mat, for some space-based reason, I get a funny mat with 3 legs on it.


Isnt there a better simpler and more efficient system?


Lets discuss

Thanks. IJR

RE: What is the efficient foundation system for elevated tanks?

2
If tension loading is the problem, couldn't you use individual footings with helical anchors (CHANCE or Atlas piers) to provide the uplift resistance?

RE: What is the efficient foundation system for elevated tanks?

(OP)
Thanks KAM

Your single footing suggestion is most welcome.

Do you want to give me more info on helical anchors. Never heard of them before


Once more thanks

IJR

RE: What is the efficient foundation system for elevated tanks?

IJR,
Why not a circular strip footing. I found it to be very economical for a masonry water tank (60m3). U will also realise its strapping advantage.
What do u propose against overturning  when tank is empty?
Riz

RE: What is the efficient foundation system for elevated tanks?

(OP)
Riz,

Nice to have you back. My problem is NOT about TANK ON GRADE. It is about ELEVATED TANK supported on 4-steel legs, braced between one another.

Thanks for commenting on ring foundations, which I usually use for tanks on grade. You mentioned strapping there which I never thought about. Thanks for that.

Regards,

IJR

RE: What is the efficient foundation system for elevated tanks?

Agree with KAM.  We have had to retrofit towers for additional loading and the anchors worked well.  Combinations of footing and anchors can reduce the footing mass for overturning moment.

RE: What is the efficient foundation system for elevated tanks?

(OP)
Thanks Ron, I am now after helicals. Guess what, we face this problem all the time, and I usually end up relying on soil mass. There was a day I had this dream: a chunk of soil mass melting like ice-cream and a bunch of columns flying like a stick.

Thanks once more and again

IJR

RE: What is the efficient foundation system for elevated tanks?

IJR,
The circular strip footing  was for an elevated tank. U can elect to taper the ends for economising concrete.
Riz

RE: What is the efficient foundation system for elevated tanks?

(OP)
Riz, I havent yet understood you. If you dont mind come back and lets get you more clearly.

I have a feeling you probably have a point, insisting on circular strip footing.

I have four steel columns to carry the tank 8m (24ft above), sort of a braced frame.

Right now I cant figure out how to run a circular strip footing to contain the column locations.

Please let me see your point closely.

Respects,
IJR

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! Already a Member? Login



News


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close