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!

*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.

Jobs

buoyancy design

buoyancy design

(OP)
Buoyancy design for structure with conventional steel columns and rigid mat foundation. What safety factor for buoyancy design is required? To resist buoyancy forces, can floor live loads above be used or only dead load?

RE: buoyancy design

We use buoyancy factor of safety of 1.5.

Don't usually use live loads at all unless there is some assurance that part of the live load will definitely be there all the time....That usually makes it into a dead load.

RE: buoyancy design

I agree with JAE that live loads should not be used for resisting flotation loads.

In the UK we use a MINIMUM factor of safety of 1.1 against flotation based on the highest credible water level around the structure (more often 1.2 is used).  The reason for the low FoS is based on the fact that you know EXACTLY what the uplift force due to water load is.

Andy Machon

 
 

RE: buoyancy design

Andy:  that makes sense....the 1.5 factor was just out of my head related to the 1.5 SF against overturning.  But you're right...the buoyancy is quite well defined.

RE: buoyancy design

    1

RE: buoyancy design

I have used a S.F. of 1.2 for foundations supporting non-building type structures (i.e., foundations for tanks, silos, transformers, etc.) and 1.5 up to 2.0 for foundations supporting buildings.

The following safety factors are recommended by "Duncan" in his foundation design book:

"S.F.=2.0 for basements and other parts of buildings subject to severe damage due to uplift"

"S.F.=1.5 for underground tanks and vaults not structurally connected to the building proper"

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

eBook: Metal 3D Printing
Metal can provide strength like no other material can and, throughout our history on Earth, humans have learned to harness metals for ever greater specialized applications, from radiation shielding on spacecraft to conductive components on circuits. Download Now

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