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

Unconfined strength and Net all. bearing value

Unconfined strength and Net all. bearing value

(OP)
What is the relation between these two numbers, if any?

RE: Unconfined strength and Net all. bearing value

If you are running the unconfined compression test, I'll go ahead and assume that you are dealing with a fine-grained (i.e., cohesive) soil.  Therefore, let's discount any contribution from internal friction.

According to the Terzhagi equation, for phi=0 (as appropriate for soils without internal friction), Nc=5.7 so qult=cNc.  For undrained analyses, c=Su (cohesion equals the undrained shear strength.  Undrained shear strength is equal to one-half the unconfined compressive strength.

So, ultimate bearing pressure would be:

qult=5.7*qu/2 or qu*5.7/2 or 2.85*qu

If you consider a safety factor of 3 q-allowable is then equal to:

q-allow=0.95*unconfined compressive strength. Heck that's about like saying the allowable bearing pressure is equal to the unconfined compressive strength!!

Wow!  That was easy, eh?

f-d

¡papá gordo ain't no madre flaca!

RE: Unconfined strength and Net all. bearing value

Nice explanation fattdad.

I might add, also check settlement & differential settlement, since it can lower your design allowable bearing pressure.

www.FoundEng.com  

RE: Unconfined strength and Net all. bearing value

(OP)
papa gordo, muchas gracias.
 

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


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