Performance Evaluation and Design of Seismic Isolation Systems with Geometric Nonlinearity for Important Equipment
Journal
World Conference on Earthquake Engineering proceedings
Journal Volume
2021
Start Page
2g-0281
ISSN
30065933
Date Issued
2021
Author(s)
Hsu T.-W.
Abstract
Earthquakes pose risks to sensitive equipment in a structure and sometimes can induce significantly economic loss. A widely utilized technique to mitigate seismic response is to install an isolation system underneath the equipment; however, excessive displacements along isolation layers may be found during severe earthquakes. Viscous dampers are recommended to be placed along the isolation layer. Still, this combination is only designed for a certain level of earthquakes and may not be effective in a small or moderate earthquake event. In this study, an isolation system with geometric nonlinearity of viscous dampers is proposed to be adaptive with different levels of earthquakes. For example, this configuration provides a better reduction in acceleration responses during small to moderate earthquakes, while the excessive displacement responses can be effectively reduced during severe earthquakes. To understand dynamic behavior of this system, a serious of investigations are carried out. The features of the effective control force are explored by the effective damping, and the phase plane analysis is conducted to understand the isolation system behavior. Moreover, this isolation system under harmonic excitation is investigated to understand generalized frequency-domain performance. Control effectiveness of the proposed isolation system is also evaluated under nonperiodic excitation such as earthquakes and compared with the conventional isolation system. To meet the dual performance criteria, a design procedure of the proposed isolation system is also established. As found in the results, the viscous damper with geometric nonlinearity enhances seismic isolation performance to be effective in all levels of earthquakes.
Subjects
Averaging Method
Geometrically Nonlinear Viscous Dampers
Dual Control Objectives
Seismic Isolation
Seismic Protection of Equipment
Publisher
International Association for Earthquake Engineering
Type
conference paper