The role of kinematic interaction on measured seismic response of soil-foundation-structure systems

Kinematic interaction transfer functions, defined as the ratio of foundation input motion to free field motion, are commonly applied, while the motion measured at the foundation may differ from that of a hypothetical foundation input motion. Results from series of centrifuge experiments on a foundation-structure model, and two foundation models revealed that: (1) inertial interaction significantly affects the lateral and rocking transfer functions around structural flexible-base natural frequencies; (2) while amplitudes of the lateral transfer functions of the foundation-structure model are smaller than those of the two other the physical models, amplitudes of the rocking transfer functions are larger; thus, using available models may lead to over-reduction and over-introduction of lateral and rocking foundation motions, respectively; (3) the effect of foundation mass is not significant; (4) increasing the motion intensity decreases the incoherence parameters; and (5) incoherence parameters had good correlations with ground motion parameters and soil shear wave velocity. •Inertial effect on interaction is around structural flexible-base natural frequency.•Kinematic interaction transfer functions depend on structural mass.•Kinematic interaction can be over- or under-estimated using analytical methods.•Good correlations exist between incoherence parameter and ground motion parameters.•Good correlation exists between incoherence parameter and shear wave velocity.