×
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

High Uplift forces in shallow foundations

High Uplift forces in shallow foundations

High Uplift forces in shallow foundations

(OP)
Hi, what can be the best options to deal with high uplift forces in shallow foundations? This is a warehouse. Soils are unsaturated medium stiff to stiff elastic silts. I am thinking on increasing Df so I can get more overburden on the footing. Thanks in advance for your opinions.

RE: High Uplift forces in shallow foundations

I don't know enough to say it's the best option, but increasing Df or the thickness of your footing are some of the simplest solutions, and ones that I see implemented regularly. Then it's just a matter of determining which is more expensive, more excavation (consider if dewatering will be req'd) or more mass concrete.

RE: High Uplift forces in shallow foundations

I suspect your need for this resistance is when weather is rough. Many times this is during heavy rainfall events and sometimes the ground water has high elevations, meaning soil density is its submerged unit weight, significantly reducing its effectiveness. Same would go for the footing unit weight, no longer 150 pcf.

RE: High Uplift forces in shallow foundations

(OP)
OG, actually I got high uplifts from the structural analysis from the structural engineers. I assuming that because it is a warehouse with large spans and openings, uplift forces due to wind are high. I am also located in a quite active seismic area. Groundwater is deep (more than 5 meters below ground surface). We may need to go for short helical piles if uplift is really high. Thanks again for the input.

RE: High Uplift forces in shallow foundations

Put the footing deeper so that you have more soil overburden on top. Increase the size or thickness of the footing. Or, use a grade beam to tie it to a nearby adjacent footing (i.e. make it into a combined footing).

Combined footings work great when you're tying the two columns in the frame together, because the one in compression will really help to stabilize the one that went into tension.

RE: High Uplift forces in shallow foundations

(OP)
Thanks for the responses. I have to look at the plans but since we may not have columns closely spaced perhaps combined footings will be difficult to implement. Anyways, as always thanks for your opinions.k

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