The Minnesota Department of Transportation (MnDOT) adopted a new dynamic pile driving formula in 2013, replacing the formula that had previously been used to estimate nominal pile resistance for MnDOT projects. The new formula, called the Minnesota Pile Formula 2012 ("MPF12"), was developed based on an extensive nationwide database of driven piles that included pile sizes and installation methods similar to MnDOT practice. The database included soil data, pile driving data, hammer data (including energy measurements), and other necessary information from the time of drive to calculate the estimated nominal resistance based on the MnDOT dynamic formula. The dataset included static load test data which provided reference static nominal resistances. A subset of data used for the development of MPF12, based on installations consistent with MnDOT practice, did not contain any piles from Minnesota, as MnDOT at that time had no companion static load test data. Following the formula development work, there was interest in validating the MPF12 calibration with local data to confirm that the static nominal resistance predicted by MPF12 agrees reasonably well with static nominal resistances assigned from static load testing. This paper provides a preliminary evaluation of MPF12 by examining several static load tests recently performed on MnDOT projects. Comparisons are made of nominal resistance predictions by the former MnDOT dynamic formula, PDA/CAPWAP estimates, and MPF12, using the Davisson offset failure criterion from static load tests ASTM D1143 as a reference value.
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