Evaluation of Rocking and Coupling Rotational Linear Stiffness Coefficients of Adjacent Foundations

This paper presents closed-form expressions for rocking spring stiffnesses and coupling interaction rotational spring stiffnesses for a set of closely spaced footings. Substructuring is used to derive analytically the exact reduced order spring models of the system. The stiffness coefficients of this reduced order model are determined by using (1) an extended, novel application of Boussinesq's surface displacement of a point-loaded half-space and (2) an empirically derived formulation that makes use of both finite-element and experimental results. Further validation suggests that, within the scope of epistemic uncertainty present in the physical world, the interaction formulas between two footings are sufficient for more general multifooting interaction cases.