Tensile Response of Pile Groups under Compression Part 2: Analysis

A semi-empirical procedure was developed for analyzing the effect of compression on tensile response of pile groups based on the concept of interaction factor and the experimental results on model single piles and pile groups embedded in a uniformly graded medium dense Indian Standard Sand. Correction factors for tension, pile shape and limited depth of soil media were suggested, which were applied to the basic interaction factors for compressive loads to make them applicable for tensile load. Using the principle of superposition, the method of analysis for two-pile group was extended to predict the efficiency in tension for four- pile groups. A semi-empirical formulation was derived for percent decrease in interaction factor due to compression. Results obtained from the developed predictive model were compared with the experimental studies conducted by the author and the analytical results were in good agreement with experimental findings. The highest efficiency in tension for almost all the cases was obtained at 25% compressive load and the lowest at 100% compressive load.