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.


Link To This Forum!

Partner Button
Add Stickiness To Your Site By Linking To This Professionally Managed Technical Forum.
Just copy and paste the
code below into your site.

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