Shake Table Testing of a Full-Scale Five-Story Building: System Identification of the Five-Story Test Structure

Abstract

A full scale five-story reinforced concrete building was built and tested on the NEES-UCSD shake table. The purpose of this test was to study the response of the structure and nonstructural components and systems (NCSs) and their dynamic interaction during seismic excitations of different intensities. The building specimen was tested under base-isolated and fixed-based conditions. To analyze the effects of the construction process, NCSs, the isolation system and structural/nonstructural damage on the dynamic properties of the building, a sequence of dynamic tests were performed on the test specimen, including ambient vibrations, impact/free vibration and forced vibration tests, the last including low amplitude white noise (WN) and seismic base excitation. In this paper, the measured response data from accelerometers are used to estimate the modal parameters (natural frequencies, damping ratios and mode shapes) of the building at different stages of construction, during the placement of NCSs and at different damage states of the structure and NCSs. Different system identification methods, including output-only and input-output, are used for this purpose. The results clearly show the effects of changing the state of the building on its equivalent linear dynamic properties, providing significant insight on the effects, absolute and relative, of the construction activities, NCSs and structural/nonstructural damage on the modal properties of the building.