DYNAMIC CHARACTERISTICS OF A SEISMIC SHAKE-TABLE TESTING FACILITY FOUNDATION

This paper presents the results of an experimental and analytical study of a 550 m3 concrete foundation below a shake-table testing facility. This facility will house two shaking tables, which will be used for seismic evaluation of components and structural systems. One of the tables is a 6-DOF 4 m square table and the other is a high payload, long-stroke, uniaxial 6.5 m by 7 m table. A finite element (FE) model of the foundation was developed based on design drawings and site soil data for the new Earthquake Engineering Research Facility being built at the University of British Columbia in Canada. The purpose of the model was to determine the expected behavior and response of the foundation to loading from various dynamic tests that could be run on the 1-DOF or the 6-DOF shake-table. The modal analysis was done using commercial nonlinear FE software and sensitivity studies were conducted for various parameters affecting the model. Upon construction of the building foundation, an ambient vibration test will be performed to determine the actual natural frequencies and mode shapes of the structure. Results of the experimental testing will be used to calibrate and update the FE model of the foundation.