Adaptive Stiffness Structures with Dampers: Seismic and Wind Response Reduction Using Passive Negative Stiffness and Inerter Systems

High-rise structures and large-span bridges have low vibration frequencies intrinsic damping hence are subjected to multimode vibrations under environmental excitation. Supplementing is a viable means suppress such vibrations. The amount of supplemental nevertheless limited as the devices in practice can only be attached structure at positions while displacements or relative small. Introducing negative stiffness, passively by stiffness (NSDs) inerters, device an effective enhancement approach. This study focuses on effects dampers enhanced NSDs inerters for flexible structures, with emphasis frequency-independence (NSDs)/dependence (inerters) introduced stiffness. Tall buildings/bridges outrigger systems incorporating (NSDOs) (IDOs) taken examples demonstration response mitigation performance. First, principle equal modal applied tuning IDOs achieve maximal target mode. Then, equivalent NSDO determined same level Subsequently, ratios first several modes compared building respectively tuned NSDOs. results show that when particular mode (e.g., second mode) almost no effect lower (first mode)—as what achieved conventional damped outriggers (CDOs). tend lock motion between perimeter columns higher structural because their frequency dependence. However, NSDOs comparable all CDOs independence. It also found it might preferable use small inertance requires large absolute value, although adding levers values demonstrated recently author. findings been confirmed numerical analyses typical seismic wind loading. Practical implementable NSD rate-independent developed based classical Maxwell—Weichert model help mitigate modes, which subject future study.