Accuracy of pile capacity from static analysis

Abstract

This research evaluates accuracy and precision of pile capacity calculation by Meyerhof (1976)method by calibrating the predictions with results of static and dynamic pile load tests for piles with their tips embedded in sand.  The skin friction predictions are calibrated with results of dynamic pile load tests.  The end bearing predictions are calibrated with results of static and dynamic pile load tests.  The study finds that pile capacities from dynamic pile load tests are 63% and 68% of those from static pile load tests for bored and driven piles, respectively.  The calculated end bearings are 21% and 52% of actual end bearings for bored and driven piles, respectively.  The calculated skin frictions are 42% and 54% of actual skin frictions for bored and driven piles, respectively.  The calculated ultimate pile capacities are 34% and 59% of pile capacities from static pile load tests.  It is also found that the calculated skin frictions are more precise than the calculated end bearings.  The end bearings have COV of 0.88 and 0.74 for bored and driven piles, respectively.  The skin frictions have COV of 0.46 and 0.32 for bored and driven piles, respectively.  Finally, the proposed factors of safety are 5, 1.5, and 2.5 for end bearing, skin friction, and ultimate capacities, respectively.