Input energy reduction-oriented control and analytical design of inerter-enabled isolators for large-span structures

Abstract

Seismic isolation technologies for large-span structures have rapidly developed alongside the popularization of the seismic resilience concept. To produce a high-efficiency isolation technology with lower energy dissipation demands, this paper proposes a novel inerter-enabled isolator (IeI) and a tailored input energy reduction-oriented design method. The inerter-based damper within the IeI is developed by combining the dashpot, tuning spring, and two inerters to facilitate the optimization of inerter distribution. Assuming the large-span structure remains linear, the overall seismic input energy of the large-span structure with IeIs and its allocation in the superstructure and additional damping are quantified using stochastic energy analysis. The advantages of the IeI over the conventional linear viscous damper (LVD) isolator are elucidated through dimensionless parametric analysis. Based on the results of parametric analysis, an input energy reduction-oriented design method is proposed for the IeI, along with an easy-to-follow diagram that helps with preliminary design in practical applications. The effectiveness of the IeI and the proposed design method is validated through a design case study of a benchmark large-span structure. The results demonstrate that the IeI reduces the seismic response of large-span structures by simultaneously employing the input energy reduction effect of grounded inerters with the damping-enhancing effect of inerter-based dampers. The proposed design method effectively balances the performance of controlling the large-span structure and the isolator displacement. Under consistent control performance and isolator displacement constraints, the IeI requires much less damping coefficient and energy dissipation capacity than the conventional LVD isolator. Moreover, leveraging the damping enhancement and input energy reduction effects, the IeI achieves comparable control performance to the conventional LVD isolator, even under stricter isolator displacement constraints.