Investigation of the accuracy of the dynamic methods of capacity estimation of piles

Capacity estimation of piles using dynamic methods is considered in this paper. Commonly used dynamic methods in Sri Lanka, high strain dynamic load testing and pile driving equations are considered in detail. The accuracy of the CAPWAP method of capacity prediction was discussed considering the results of the available comparison studies. Considering the CAPWAP predicted capacities and the capacities estimated from the Case method, the applicability, of the commonly used Case damping factor of 0.5 was investigated. Furthermore, Case damping factors to be used in the field high strain dynamic load testing are also suggested. The capacities estimated from the CAPWAP analysis of the dynamic load test data and the measured set of the pile during high strain dynamic load testing are used to evaluate the accuracy of the capacity predicted by pile driving equations. Based on the data collected, the accuracy of each pile driving method is discussed. Furthermore, the factors affecting the accuracy of the pile driving equations are also investigated. Moreover, the factors of safety to be used with different methods are also presented