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


Point Load Testing

Point Load Testing

Point Load Testing

Is there a non-graphical method (Brock and Franklin) method of converting Is to Is50? (e.g. formulae)

Reading from the correction graphs is a little clumsy and can give errors.

Thanx in advance for your help.

RE: Point Load Testing

In my opinion, the point load not a very accurate test but tend to give an approximation of strength. In this case errors according to graph ranges are not a big deal.  Otherwise you have to work on the equation of the curve - if mentioned.

RE: Point Load Testing

Formula is

Is(50) = F x Is

where F = (De/50)** 0.45    (** means to the power of 0.45)
De is the "equivalent core diameter"

De**2 = D**2 for diametrical test,
De**2 = 4A/phi for axial. block and lump tests
  (A = WD= minimum cross sectional area of a plane through platen contact point)

Reference :
1.ISRM - "Suggested method for determining Point Load Strength"
2. N. Brook , "The equivalent core diameter method of size and shape correction in Point Load testing", Intl Journal of Rock Mech., Mineral Sci. and Geomechanics  vol 22 no. 2 pp 61-70, 1985


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!


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