Input and system identification of the Hualien soil–structure interaction system using earthquake response data

Abstract

SUMMARYThis paper presents an input and system identiÿcation technique for a soil-structure interaction system using earthquake response data. Identiÿcation is carried out on the Hualien large-scale seismic test structure, which was built in Taiwan for international joint research. The identiÿed quantities are the input ground acceleration as well as the shear wave velocities of the near-ÿeld soil regions and Young's moduli of the shell sections of the structure. The earthquake response analysis on the soil-structure interaction system is carried out using the ÿnite element method incorporating the inÿnite element formulation for the unbounded layered soil medium and the substructured wave input technique. The criterion function for the parameter estimation is constructed using the frequency response amplitude ratios of the earthquake responses measured at several points of the structure, so that the information on the input motion may be excluded. The constrained steepest descent method is employed to obtain the revised parameters. The simulated earthquake responses using the identiÿed parameters and input ground motion show excellent agreement with the measured responses.

Identification of structural and soil properties from vibration tests of the Hualien containment model

“…The present study conÿrms the 15-18% di erence between the shear-wave velocities in directions D 1 and D 2 in the top layer of soil below the foundation. Since similar results have been found [13][14][15][16] from analyses of earthquake ground motions recorded at free-ÿeld downhole arrays located away from the foundation it must be concluded that soil anisotropy must be involved.…”