Dynamic Lateral Pile‐Group Effects

Abstract

Dynamic lateral pile‐group effects are studied parametrically for a linearly elastic soil‐pile‐structure system. The soil layer is assumed homogeneous, and all piles are identical and vertical. Pile‐group responses for the soil‐pile systems used in this study are affected primarily by the spacing ratio, the dimensionless frequency, and the directional angle between two piles. Spring and damping coefficients of a pile group are strongly frequency dependent. Spring coefficients of a pile group can be negative for a clustered group, and they can be larger than a simple summation of single pile stiffnesses. Damping of a pile group also is frequency dependent, and it can be either larger or smaller than that of a surface footing with identical plan dimensions. Distribution pat terns of shear and moment among piles are affected largely by frequency. The study demonstrates potential importance of dynamic pile‐group effects. Also, it provided a procedure to generate theoretical pile‐group effects for dynamic analyses of complex soil‐pile‐structure systems.