A finite-element computer program, Soil-Pipe Interaction Design and Analysis (SPIDA), was developed for buried concrete pipe. The purpose of the program is to update the current concrete pipe design methods based on the Marston-Spangler approach with the expectation of reducing the cost of the installations and providing a more accurate representation of field conditions. Separate computer models were prepared for a positive-projecting embankment installation and a vertical-sided trench installation to optimize the representation of these two different cases. A wide range of bedding and soil conditions can be simulated. Experience with SPIDA indicates that it gives reasonable results. The program has advanced to the stage where it is ready for trial applications in pipe design.

Research was under taken to develop a finite-element computer program for design and analysis of buried concrete pipe. The resulting program, Soil-Pipe Inter action Design and Analysis (SPIDA), is described and some examples are given of results obtained with it. Some of the details of the suppor ting research have been given elsewhere (l). The purpose of the program is to update the current concrete pipe design methods based on the Mar ston-Spangler approach. This effort is expected both to reduce the cost of the installations and to provide a more accurate representation of the wide range of conditions experienced in the field. The guidelines for the development of the com-