Using supplemental linear viscous dampers for experimentally verified base-isolated building: Case study

Abstract

As a way to reduce structural vibration, many buildings are initially intended to be base-isolated. However, because of the base isolators' inherent nonlinear behavior, particularly in earthquake-prone areas, buildings equipped with base isolation systems may experience significant displacement demands. Therefore, in certain situations, it might be required to use additional damping devices to control the seismic response of base-isolated buildings. This study examines three different building models: Fixed Base (FB), Isolated Base (IB), and Isolated Base with installed Viscous Dampers (IB&VD) in the base layer of the building. Sosokan, a nine-story structure on Keio University's Yagami Campus, is utilized for this purpose. The building is modeled in MATLAB. A state-space representation of the building with a Maxwell-type viscous damper model is used. The responses of the building models with FB, IB, and IB&VD are evaluated by time history analyses using eight ground motion records. Certain engineering requirements criteria, such as inter-story drift ratios and absolute acceleration, are taken into consideration while evaluating the findings of the analysis. Based on one of this study's main findings, a base-isolated building with passive viscous damping in the base layer could significantly reduce both maximum seismic displacement and acceleration. Maximum acceleration and inter-story drift are lowered by up to 92% and 89%, respectively, when IB&VD is scaled to the FB model. Based on the results of this study, passive viscous dampers combined with building base isolation are not only useful for multi-objective optimization (i.e., reducing acceleration as well as inter-story drift) but they can also be used to reduce high-frequency accelerations, which could be important for building equipment that is sensitive to acceleration.