SPT Energy Transfer Measurements for Liquefaction Evaluations in the Northeast

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Johnsen, Lawrence F.; Bemben, Stanley M.; Jagello, Jon J.
University of Missouri--Rolla
Geotechnical Engineering
conference paper description
Energy measurements were made during Standard Penetration testing at Northeast locations with 16 drilling rigs having various energy transfer mechanisms including automatic safety hammers, wire line safety hammers, rope and cathead safety hammers and donut hammers. The energy measurements were used to correct the field N values to the standard 60% reference energy transfer. Examples are provided to illustrate the significant effect which the energy transfer efficiency has when working with Building Codes. The uncertainty regarding the use of field N values as opposed to energy corrected N values when using the codes is discussed.