City Research Online

Abstract

In recent years, inerter vibration absorbers (IVAs), such as the tuned mass damper inerter (TMDI), attracted much attention in the literature for reducing seismic displacement demands of base isolated structures (BISs). Several theoretical studies reported reduced BIS seismic demands with increasing inertance endowed by a grounded inerter element but adopted mostly idealized linear dynamical models. Herein, the potential of TMDI-configured IVAs for seismic response reduction of BISs modelled as single-mass structures is assessed under the combined effects of nonlinear inerter and structural behaviour. To this aim, experimental data from a shaking table testing campaign are considered utilizing a custom-built flywheel rack-and-pinion grounded inerter prototype with variable inertance along with high damping rubber bearings in the isolation layer and in the BIS-to-absorber link. White noise excitation and an ensemble of six ground motions (GMs) with different frequency content are used in the tests for which bearings exhibit softening nonlinear behaviour. Experimental results demonstrate improvement of BIS nonlinear seismic response in terms of displacement and base shear with increasing inertance for nonlinear and non-optimally designed TMDIs. It is found though that non-optimally tuned IVAs may be detrimental to BIS acceleration response depending on the GMs time-varying frequency content signatures as captured by the continuous wavelet transform spectrogram. Lastly, it is concluded that representing the inerter device by a simplified linear dissipative model as opposed to a nonlinear model with friction and gear backlash suffices to trace the BIS response with acceptable accuracy and, thus, can be used for optimal seismic TMDI design.

Publication Type:	Article
Additional Information:	This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. © 2021 The Authors. Earthquake Engineering & Structural Dynamics published by JohnWiley & Sons Ltd. DOI: 10.1002/eqe.3469
Publisher Keywords:	Inerter, Base Isolated System (BIS), Tuned Mass Damper Inerter (TMDI), experimental parametric analysis, seismic effectiveness, nonlinear models
Subjects:	T Technology > TA Engineering (General). Civil engineering (General)
Departments:	School of Science & Technology > Engineering
SWORD Depositor:	Symplectic Administrator

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