GROUP is a well-accepted tool for analyzing the behavior of pile groups subjected to both axial and lateral loadings. The program was developed to compute the distribution of loads (vertical, lateral, and overturning moment up to three orthogonal axes) applied from any multiple locations in the pile cap to piles arranged in a group.

The program generates internally the nonlinear response of the soil, in the form of t-z and Q-w curves for axial loading, in the form of p-y curves for lateral loading and in the form of T-q curves for torsional loading. A solution requires iteration to accommodate the nonlinear response of each pile in the group model. Program GROUP solves the nonlinear response of each pile under combined loadings and assures compatibility of deformations and equilibrium of forces between the applied external loads and the reactions of each pile head.