Flexibility coefficients and interaction factors for pile group analysis

Abstract

Flexibility coefficients of single piles and interaction factors established for groups of two piles are presented to facilitate analysis of arbitrary pile groups exposed to static horizontal loads. Such an analysis may yield pile group flexibility, stiffness, deflection, and distribution of loads on individual piles. The data given are complete in that they include horizontal translation, rotation in the vertical plane, and cross effects between the two, making it possible to establish complete stiffness and flexibility matrices of pile groups provided with either rigid caps or arbitrarily flexible caps. Homogeneous, parabolic, and linear (Gibson's) soil profiles are considered and the piles may have a free length sticking above the ground surface. The methods of group evaluation based on superposition of interaction factors are reviewed and compared and numerical examples are given. Key words: piles, pile groups, lateral loads, flexibility, stiffness, load distribution.