Gregory Reuter, PE, PG, D.GE and Dr. Gianni Togliani published their paper on CPT/CPTu pile capacity prediction methods in the 3rd International Symposium on Cone Penetration Testing :: May 12-14, 2014 – Las Vegas, Nevada.
Numerous CPT/CPTu methods are available for predicting pile capacity. Pile capacity is not, however, a single value, because it is not only linked to the selection of the failure criterion in the load-movement curve, but it is also time-dependent (setup and relaxation). This latter condition is a very important perspective which is, unfortunately, missing from most CPT/CPTu capacity prediction methods. A case history is presented of a pile testing program where pile capacity was determined during initial pile installation, and again periodically for up to 3 years. This testing showed a continued increase in pile capacity with time due to soil setup. A seismic piezocone sounding was performed at the site, and the results were used to predict pile capacity using various published CPT/CPTu methods. As expected, the results indicate differing predicted capacities. Potential modifications to the CPT/CPTu prediction methods are discussed to address the 100-day reference time capacity goal.
Greg is a Principal Geotechnical Engineer with American Engineering Testing, Inc. in St. Paul, Minnesota. Dr. Togliani is a geological-geotechnical consultant in Massagno, Switzerland.
A copy of the paper can be downloaded from the conference site at: http://www.cpt14.com/cpt14-papers