Linear System Identification of the UC San Diego Geisel Library Building

This paper focuses on the linear system identification (SID) of the UC San Diego Geisel Library building using recorded seismic data. This study assumes that the structure is linear viscously damped and has a rigid base. Five state-of-the-art state-space-based time domain system identification methods, including two input-output and three output-only, are used to identify the modal properties of the structure by using the seismic vibration data recorded during a small earthquake. Results show that the first three modes are the global torsional and first flexural/lateral modes, while the remaining identified modes are coupled flexural/lateral-torsional modes. The identified state-space model was also used to predict the total acceleration response of the structure to the considered earthquake. This research provides a unique opportunity to study linear system identification of a large and complex real-world operational structure under seismic excitation.