Vibration mitigation of long-span bridges with damped outriggers

Chen, Lin; Liu, Zhanhang; Nagarajaiah, Satish; Sun, Lijun; Zhao, Lin; Cui, Wei

doi:10.1016/j.engstruct.2022.114873

Cited by 21 publications

(5 citation statements)

References 57 publications

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“…Then the equivalent dynamic stiffness of the damper was found based on the maximum damping force and maximum displacement of the damper. 41 The equivalent dynamic stiffness of the damper is given as shown in Table 10. Finally, this equivalent dynamic stiffness is used to approximate the dynamic stiffness of the viscous damper in real engineering.…”

Section: Determination Of the Equivalent Dynamic Stiffnessmentioning

confidence: 99%

“…First, the time‐history analysis was performed for model M1 subjected to frequently occurring earthquakes to find the maximum output force and maximum displacement of the damper. Then the equivalent dynamic stiffness of the damper was found based on the maximum damping force and maximum displacement of the damper 41 . The equivalent dynamic stiffness of the damper is given as shown in Table 10.…”

Section: Determination Of the Equivalent Dynamic Stiffnessmentioning

confidence: 99%

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Application of amplified damped outrigger in seismic design of high‐rise buildings

Xue,

Zhao,

et al. 2024

Structural Design Tall Build

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SummaryThe application of the outrigger technology effectively improves the lateral stiffness of buildings, reduces harmful deformation, enhances the seismic resistance of structures, and contributes to the rapid development of high‐rise buildings. To improve the response speed and energy dissipation of a viscous damping outrigger under seismic excitation, a viscous damping outrigger with an amplifier was proposed, and its effectiveness was verified by combining it with the seismic design of a 149.2 m high‐rise building in an 8.5‐degree intensity area. To determine the additional damping ratio of the building structure, investigations were carried out using both the code method and energy ratio method to evaluate the contribution of the damping outrigger. The damped outrigger equivalent stiffness determination method was studied, and the simplified engineering calculation method was compared against the refined finite element analysis results for engineering design purposes. The displacement amplification technique incorporated into the viscously damped outrigger can enhance the damper response speed, and increase the energy dissipation of the damped outrigger system. The application of an enlarged damped outrigger in engineering can result in an additional damping ratio of approximately 1% while simplifying the calculation method based on the additional damping and equivalent damper cut‐line stiffness, which can be useful in engineering design.

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Section: Determination Of the Equivalent Dynamic Stiffnessmentioning

confidence: 99%

Section: Determination Of the Equivalent Dynamic Stiffnessmentioning

confidence: 99%

Application of amplified damped outrigger in seismic design of high‐rise buildings

Xue,

Zhao,

et al. 2024

Structural Design Tall Build

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“…6(b), and have been used for bridge retrofit (LUSAS 2021). For long-span bridges, the application of damped outriggers will be further explored by (Chen et al 2022). The systems in Fig.…”

Section: System Descriptionmentioning

confidence: 99%

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

2022

Self Cite

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

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“…Tese studies investigated the optimal designs of damped outrigger systems with the seismic excitation modeled as a stationary stochastic process. To date, engineering applications of damped outriggers in buildings can be found in [9,35,36], and an interesting application scenario is to mitigate vibration of long-span bridges [37].…”

Section: Introductionmentioning

confidence: 99%

Stochastic Optimization and Sensitivity Analysis of the Combined Negative Stiffness Damped Outrigger and Conventional Damped Outrigger Systems Subjected to Nonstationary Seismic Excitation

Zhou

Fang

Zhang

2023

Structural Control and Health Monitoring

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In recent years, various kinds of damped outrigger systems, particularly with the negative stiffness devices, have been shown to effectively suppress excessive vibration induced by earthquake and wind. To gain insight into such systems, this paper proposes a stochastic optimization method to investigate optimal configurations of combined negative stiffness damped outriggers (NSDOs) and conventional damped outriggers (CDOs) subjected to nonstationary stochastic seismic excitation. The simplified analysis model of various combinations of damped outriggers is developed, and the state-space representation of outrigger systems is then formulated. The nonstationary seismic excitation is modeled as a uniformly modulated stationary Gaussian process with a time-modulating function following Clough–Penzien spectrum, and combining equations of motions of outrigger systems and seismic excitation gives rise to the augmented state-space representation of structure-damper-excitation and subsequently the differential Lyapunov equation. The optimal designs of damped outriggers are defined via the solution of the differential Lyapunov equation. The multiobjective optimization with Pareto optimal fronts is adopted to deal with conflicting objectives between harmful interstory drift and floor absolute acceleration. The sensitivity of negative stiffness devices on optimal objectives is also investigated. The optimal designs are further examined under real typical and near-fault earthquake records. The results demonstrate the efficacy of the proposed method and provide insight into the systems subjected to nonstationary seismic excitation. While the purely NSDO systems could have better performance with adequate negative stiffness devices, the proposed combined NSDO and CDO systems prove to be more effective with limited negative stiffness devices and thus provide more design flexibilities tailored to different application situations.

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Vibration mitigation of long-span bridges with damped outriggers

Cited by 21 publications

References 57 publications

Application of amplified damped outrigger in seismic design of high‐rise buildings

Application of amplified damped outrigger in seismic design of high‐rise buildings

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

Stochastic Optimization and Sensitivity Analysis of the Combined Negative Stiffness Damped Outrigger and Conventional Damped Outrigger Systems Subjected to Nonstationary Seismic Excitation

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