This paper presents the identification of the time-variant modal properties of a full-scale fivestory RC building tested on a shake table. The building was tested under fixed-base (FB) and base-isolated (BI) configurations and was subjected to a suite of earthquake motions of various intensities. The deterministic-stochastic subspace identification method is employed to estimate the variations of the modal properties of the BI building during the seismic tests by employing a short-time windowing approach. The changes of the modal parameters are tracked, analyzed, and compared to those previously identified from ambient vibrations data and low-amplitude whitenoise base excitation tests. In addition, observed and measured responses of the structure are studied and correlated with the variation of the identified modal parameters. For the base-isolated configuration, the nonlinear behavior of the isolators generates the variation of the identified natural frequencies and equivalent damping ratios of the building, which change in agreement with the input motion intensity. A high correlation between the effective stiffness of the isolators and the instantaneous frequency of the first mode is found. The effective damping ratio of the isolation system and the instantaneous damping ratio of the fundamental mode of the building are highly correlated.
|Título de la publicación alojada||11th National Conference on Earthquake Engineering 2018, NCEE 2018|
|Subtítulo de la publicación alojada||Integrating Science, Engineering, and Policy|
|Editorial||Earthquake Engineering Research Institute|
|Número de páginas||10|
|ISBN (versión digital)||9781510873254|
|Estado||Publicada - 2018|
|Evento||11th National Conference on Earthquake Engineering 2018: Integrating Science, Engineering, and Policy, NCEE 2018 - Los Angeles, Estados Unidos|
Duración: 25 jun 2018 → 29 jun 2018
Serie de la publicación
|Nombre||11th National Conference on Earthquake Engineering 2018, NCEE 2018: Integrating Science, Engineering, and Policy|
|Conferencia||11th National Conference on Earthquake Engineering 2018: Integrating Science, Engineering, and Policy, NCEE 2018|
|Período||25/06/18 → 29/06/18|
Nota bibliográficaPublisher Copyright:
Copyright © 2018 Earthquake Engineering Research Institute. All rights reserved.