The SPT Analyzer measures the energy transferred into an instrumented SPT rod. This permits the adjustment of the measured N-value to the normalized N60 for standard 60% energy transfer into the rods. Compensating for widely variable efficiencies from different SPT rigs and hammer types improves the reliability of soil strength estimates used in geo-technical designs.

This instrument includes an SPT rod instrumented with two strain gage bridges and two accelerometers. These sensors obtain the force and velocity signals necessary for the calculation of transferred energy and transfer them to the SPT Analyzer. The equipment is light and small, and operated by a high contrast touch screen that doubles as a keyboard.

This project ("Documenting Incidents of Ground failure Resulting from the August 17, 1999 Kocaeli, Turkey Earthquake.") was a cooperation of research universities and government agencies in Turkey and the USA. "I would personally like to thank you (PDI) once again for your support of this important project. Yes, indeed, Rodolfo (n.e.: Rodolfo Sancio) did an excellent job, but it was your equipment and training that made it possible. (...) The demonstrated usefulness of the equipment (...) for enabling reliable N60 numbers to be obtained cannot be ignored by the profession. Thanks again for your help."
- Jonathan D. Bray, Professor, U.C. Berkeley

The SPT Analyzer is compliant with EN ISO 22476-3:2005. ASTM D1586-08 recommends normalizing results from any SPT test using energy measurements. When these tests are performed to determine the liquefaction potential of sands, ASTM D6066-96(2004) not only recommends but mandates the normalization. ASTM D4633-05 states that the only acceptable method of determining energy for normalization of N values is by force and velocity measurements.