Physical Properties of Plywood and Waferboard as Pile Cushion Materials

The use of wave equation software (e.g., GRLWEAP) to determine driving stresses of piles requires the input of pile cushion thickness and elastic modulus. Up to this point in time, the values of pile cushion thickness and elastic modulus after a number of blows have been assumed and input into the program for an "end of drive" analysis. Based on the results of this laboratory study, two graphs and an equation have been developed that can be used to determine the thickness and elastic modulus, after a number of blows, for plywood and waferboard pile cushions.