Dynamic centrifuge tests were performed on a superstructure-footing model that was placed on a dry sand surface and subjected to two different input motions having peak accelerations of 60 cm/s2 and 249 cm/s2. Two simple analyses, equivalent linear analysis (SHAKE) and dynamic response of a structure using a sway-rocking model (SR-model) were performed. The following conclusions were drawn: (1) SHAKE and SR-model analyses can simulate the recorded response of the soil and superstructure. However, the shear wave velocity of the ground that can simulate the superstructure response by an SR-model for amax=249 cm/s2 is much smaller than that of the free field estimated using SHAKE. (2) The observed relation of the base friction force with relative displacement between the footing base and the ground surface shows strong nonlinearity when amax=249 cm/s2, which probably results from the large shear deformation of the thin layer beneath the footing
