Application of the wave equation analysis to friction piles in sand

Based on the information gathered during a design pile testing program and the subsequent construction of a large pile foundation in Quebec City, the potential and limitation of the wave equation method for analysing pile driving behaviour are demonstrated.The application of the wave equation method to instrumented precast concrete piles driven under well controlled conditions leads to excellent predictions both in terms of driving stresses and of ultimate bearing capacities.The same high quality of prediction is obtained for a steel H-pile and a precast concrete pile driven incrementally to a depth of 53 ft (16.2 m) in a uniform sand deposit. However, proper simulation of the joints is required for the precast concrete pile.On the contrary, a very poor correlation between computed and observed ultimate capacities is obtained for the production piles. This is attributed to the poor reliability of the blow counts used as input data in the classical wave equation method of analysis.