The program simulates the behavior of a pile (a slender elastic rod) and the surrounding soil (an elastic, plastic and viscous material) under the impact of a pile driving hammer. Powerful options combine the basic analysis of one hammer blow into the simulation of a complete pile driving process. Today the GRLWEAP software is recognized by many specifying agencies as the most reliable predictor of dynamic pile driving stresses, hammer performance, and either blow count or bearing capacity of an impact driven pile.