Partial mass isolation system for seismic vibration control of buildings

Summary In a previous study, the authors studied a partial mass isolation (PMI) system that through isolating different portions of story masses can provide a building with multiple inherent vibration suppressors. It was shown that the PMI strategy with isolated mass ratios (IMRs) of 0.05 or 0.90 could perform as effectively as an equivalent tuned mass damper or a base isolation system, respectively. In the present paper, the PMI system is examined in structural models with different fundamental periods. PMI configurations in a wide IMR range of (0.05:0.025:0.90) are optimized illustrating that applying an IMR of 0.25–0.50 can provide an efficient system, simultaneously satisfying the constraints related to different performance objectives (i.e., mitigating the overall building seismic responses and controlling isolated components' (ICs) responses while integrating these components into the building architecture). Simulation results reveal that using identical ICs at different stories, which have the advantage of facilitating the design and construction of the system, can lead to a near-optimal solution. It is also demonstrated that in terms of the spatial distribution of ICs, an adequate seismic performance improvement can be achieved by allocating ICs only at a subset of upper stories (e.g., top half stories), which can further simplify the PMI systems' construction.