×
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

Bearing Capacity of Bedrock

Bearing Capacity of Bedrock

Bearing Capacity of Bedrock

(OP)
If we could put a number on the bearing capacity of bedrock, what would it be?  i.e. what is the lowest number that could be used (conservative)?  I need to make a strength comparison.
Thanks in advance

RE: Bearing Capacity of Bedrock

Depends on the Rock. Many local codes have presumptive capacities for bedrock. I think AASHTO bridge design manual has them also.

RE: Bearing Capacity of Bedrock

Rock,  1500 to 11,000 psi.

RE: Bearing Capacity of Bedrock

Maybe not "bedrock", but bearing capacity of rock in piles normally starts around 1 MPa, or say 150 psi.  This is highly weathered rock, and as civilperson says, fresh rock can be very strong.

RE: Bearing Capacity of Bedrock

Unconfined compressive strength for intact rock can vary from 21.5 psi (siltstone) to 51,500 psi for bassalt.  Just using the rational method that would suggest an ultimate bearing capacity of 60 to 144,200 psi (big range).  This would equate to 4.3 to 72 tsf with an allowable bearing presure of about 1-1/2 to 24 tsf.

Here's where the body is buried:  These values are based on laboratory testing of INTACT rock samples.  The presence of joints, the condition of the joints, the orientation of joints, the presence of ground water and natural structural layering(s) can have a dramatic affect.

In summary:  You have to define "bedrock", you have to characterize the "bedrock" and you have to do a field study to understand the nature of the defects.  Then you can work up the bearing pressure.  Here's where "oriented core" can become relavent. . . .

f-d

¡papá gordo ain’t no madre flaca!

RE: Bearing Capacity of Bedrock

Try looking for references to MJ Tomlinson. Good stuff there, promise. Also Waltham's book 'Foundations of Engineering Geology', it's a bit lighter / easier going, almost like an engineering book for pure geologists!! Good stuff there also.

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