Computer Assisted Analysis - Pile Groups.

A computer assisted analysis is a reasonable alternative for obtaining reliable estimates of the performance of pile groups.  Several computer programs can assist the analysis and design of groups.

a.   CPGA.  Program CPGA provides a three-dimensional stiffness analysis of a group of vertical and/or
battered piles assuming linear elastic pile-soil interaction, a rigid pile cap, and a rigid base (WES Technical Report ITL-89-3).  Maxtrix methods are used to incorporate position and batter of piles as well as piles of different sizes and materials.  Computer program CPGG displays the geometry and results of program CPGA.

b.  STRUDL.  A finite element computer program such as STRUDL or SAP should be used to analyze the performance of a group of piles with a flexible base.

c.   CPGC.  Computer program CPGC develops the interaction diagrams and data required to investigate the structural capacity of prestressed concrete piles (WES Instruction Report ITL-90-2).

d.   CPGD.  Computer program (Smith and Mlakar 1987) extends the rigid cap analysis of program CPGA to provide a simplified and realistic approach for seismic analysis of pile foundations.  Program CPGD (in development stage at WES) includes viscous damping and response-spectrum loading to determine pile forces and moments.