cbr correlation

[wvnomad]

The Marine Corps has recently purchased a new "Soils Testing Kit" which includes a Dual Mass-Dynamic Cone Penetronemeter. This kit also includes a Vertec Data Acquisition System with a Soil Moisture Probe. It is awesome equipment which works well for us and our mission which is of an expeditionary nature (structure design life of six months to two years). One of the down sides is that many of our FM's and TM's which predate the use of the DCP refer to the soils bearing capacity in pounds per square foot or tons psf.

As a means to make a quick correlation between the two I (and I am not a college trained Engineer by no means) believe that we can take the 3000psi which is the standard effort used in a CBR test and multiply it times the CBR expressed as a percent to arrive a soils strength per squard inch and doing the relative converstion to lbs/psf or tons/psf. Keeping in mind the expeditionary nature of our work, is this feasible?

 

[DBNodurf]

I am in possession of a correlation between CBR and "bearing pressure" for this type of DCP...

704-436-8080

D. Bruce Nothdurft, MSCE, PE, PG, M.ASCE, etc, etc,...
Principal Engineer/Geologist
Atlantic Geoscience & Engineering
Charlotte, NC

 

[Focht3]

Bruce!

Is it "super double top secret - I'd tell you, but then I'd have to kill you" stuff?!





Please see FAQ731-376 by [blue]VPL[/blue] for tips on how to make the best use of Eng-Tips Fora.

 

[sc]

Bruce,

Given other discussions on this topic and the number of variables involved, I would love to see the correlation as well.

 

[DBNodurf]

I have a paper entitled "Dynamic Cone Penetrometer Criteria for Evaluation of Subgrade and Aggregate Base Courses" by Mohammed A. Gabr, Phillip C. Lambe, et.al. of NC State Univ (Moo Yoo) dated August 1999. It describes results of tests using both the Scala DCP (some call it the Kessler DCP; I'm not sure they are really the same) and the CBR, and offers a correlation. NCDOT has actually been using a correlation, presumably from this report.

I believe Messrs. Tom Hearne and Shane Kepley of the NCDOT Pavement Management System helped with the report. Tom can be reached at (704)983-4019 or email: thearne@dot.state.nc.us

Shane appears to not be in that department any longer.

http://pmu.dot.state.nc.us/

I have a copy of a handout from DOT with a correlation which I can send you if you provide me an address; I also might get it scanned in and could then email it as a pdf...

D. Bruce Nothdurft, MSCE, PE, PG, M.ASCE, etc, etc,...
Principal Engineer/Geologist
Atlantic Geoscience & Engineering
Charlotte, NC