One shallow foundation, 3 m x 3 m in plan and embedded 0.9 m, has been dynamically loaded at
the National Geotechnical Experiment Site (NGES) on the campus of Texas A&M University
(TAMU) via NEES equipment. The TAMU NGES site has been extensively characterized via
both in situ and laboratory soil testing techniques, including shear wave velocity via both
borehole and surface wave methods. Two dynamic loading devices (Thumper and T-Rex from
University of Texas at Austin) were implemented in several configurations to excite the footing
in vertical, horizontal sliding, and rocking vibration modes. The dynamic load and vibration
responses were measured via appropriate electronic instrumentation. Utilizing appropriate
equations of motion and system parameters (e.g., mass moment of inertia), dynamic impedance
functions were backcalculated for each vibration mode from the measured load and vibration
responses.
