To address the vertical displacement estimation of conventional pile groups subjected to mechanical loads, various numerical and analytical methods have been proposed. These methods include the finite element method [e.g., 2,3], the boundary element method [e.g., 4,5], the finite difference method [e.g., 6], the interaction factor method [e.g., 7,8–11], the equivalent pier and raft methods [e.g., 12–14], and the settlement ratio method [e.g., 15]. The finite element method, while providing the most rigorous and exhaustive representation of the pile group-related problem, is generally computationally expensive and considered mainly a research tool rather than a design tool. Conversely, the versatility of simplified (approximate) methods, such as the interaction factor approach that allows capturing the (e.g., vertical) displacements of any general pile group by the analysis of the displacement interaction between two identical piles and by the use of the elastic principle of superposition of effects, makes them attractive as design tools because they allow for the use of expedient parametric studies under various design conditions.
