Seismic Response Analysis of Multistory Floating Floor Structures (FFSs) With the Variant Tuned Mass Damper Inerter (V‐TMDI)

ABSTRACT Floating floor structures (FFSs) represent a powerful seismic protection technique that can substantially decrease the responses of both the main building and the attached nonstructural components. Nonetheless, the high flexibility of the isolation layer results in significant relative motion between the floated floor slabs and the primary structure, a major drawback of this system. To overcome this limitation, this paper introduces a variant tuned mass damper inerter (V‐TMDI) aimed at further improving the seismic performance of FFSs. First, an analytical model of a multistory FFS equipped with a V‐TMDI is formulated, and the governing equations are derived. The effects of the V‐TMDI frequency ratio and damping ratio on the stochastic responses of the FFS are examined. Next, a numerical optimization framework is developed to identify the optimal V‐TMDI parameters. A parametric investigation is subsequently conducted to examine how the configuration of the combined FFS–V‐TMDI system affects these optimal parameters. The robustness of the V‐TMDI is further evaluated by comparison with a traditional V‐TMD. Finally, time‐history analyses of a multistory building subjected to earthquake excitations are performed to confirm the efficiency of the proposed approach. The results indicate that, compared with the fixed‐floor structure (FS), the maximum roof displacement of the main structure, the first‐story interstory drift, and the absolute acceleration of the top floating floor slab in the FFS with V‐TMDI are reduced by approximately 53%, 50%, and 67%, respectively. Moreover, compared with a conventional FFS, the V‐TMDI reduces the peak relative displacement of the top‐floated floor slab with respect to the main structure by approximately 50%.