Tensile Response of Pile Groups under Compression Part 1: Experimental Investigations

The contemporary state-of-the-art analysis and design of piles and pile groups for tension neglects the compressive load imposed by superstructure on the pile foundation. The results of an experimental investigation on model single piles and pile groups embedded in a uniformly graded medium dense Indian Standard Sand, grade-2 (Ennore sand) poured to a desired density by pluviation were reported. The piles were tested under pure compressive and pure tension, as well under predefined combinations of the two. The experimental results were analyzed for various parameters such as net tensile capacity, efficiency of pile group, unit skin friction and their variations. Net tensile capacity decreased with increase in compressive load. The highest efficiency of pile groups under combined loading (Tension and Compression) was observed at 25% compressive load and mostly at 6d pile spacing.