Book excerpt: When the soil immediately below the base of a structure will not provide adequate bearing capacity, piles can be used to transfer load from the structure to soil strata which can support the applied load. This report deals with analysis of the lateral interaction of pile shaft and soil. Examples of such problems encountered by the Corps of Engineers are single-pile dolphins and baffles for grade control structures. A computer program called COM624, along with documentation, was developed at the University of Texas (UT) at Austin, to analyze laterally loaded pile problems. Analysis performed by program COM624 is dependent upon soil parameters input to the program. These soil parameters take the form of curves which simulate the nonlinear interaction of the pile and the surrounding soil. The UT Report also presented criteria for developing these soil response curves in various types of soils. This report consolidates the information available on laterally loaded pile analysis and provides supplementary data on Program COM624 (redesignated as COM624G). It describes modifications made in the input procedures and the addition of graphics options.