Fictitious pile method for fixed-head pile groups with dissimilar piles subjected to horizontal loading

Abstract

Pile groups are traditionally designed with similar piles in length, diameter, and property. However dissimilar piles may occur in the cases of foundation reuse and economical building design. This paper develops a fictitious pile method for the interaction factors between two dissimilar piles in a pile group that have different dimensions and properties. The effects of different pile lengths/properties on the horizontal load distribution, group efficiency factor and group reduction factor are studied here by using the fictitious pile method. Based on the principle of superposition and the concept of interaction factor, the proposed approach avoids the full analysis on pile groups and thus significantly improves the calculation efficiency. The horizontal load distributions for the fixed-head pile group with dissimilar piles by the proposed method match well with the results by the finite element method. The parametric study shows that, for stiffer pile group, the corner pile length is an important parameter affecting the fixed-head pile group behavior under horizontal loading.