Dynamic Interaction Factors for Floating Pile Groups

Keywords: Foundation, Piles, Pile Group, Dynamic Analysis, Interaction Factors, Vertical Loading, Horizontal Loading, Rocking Loading, Oscillations, Waves, and Harmonic Vibrations.

Abstract: A comprehensive set of dimensionless graphs of complex-valued dynamic interaction factors versus frequency is presented for vertical, horizontal, and rocking harmonic excitations at the head of individual piles. These readily-applicable graphs have been developed with a rigorous analytical-numerical formulation for two idealized soil profiles (a homogeneous halfspace with modulus proportional to depth) and three pile separation distances (3, 5 and 10 pile-diameters). A wide range of values have been parametrically assigned to pile slenderness and pile-to-soil stiffness ratios. The results are discussed at length to gain valuable insight into the nature of dynamic pile-soil-pile interaction. Geotechnical and earthquake engineers can use the presented graphs exactly as they use the classical interaction factors for static deformation analysis of pile groups.