Optimum Parameters for Large Mass Ratio TMDs Using Frequency Response Function

Yahyai, Mahmood; Zebarjad, Leila; Head, Monique; Shokouhian, Mehdi

doi:10.1080/13632469.2019.1624228

Cited by 15 publications

(7 citation statements)

References 22 publications

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“…However, as discussed in previous study (e.g. [25,27,21]), reasonable variations of ξSDOF do not significantly affect the optimal TMD parameters.…”

Section: Comparison With Other Literature Solutionssupporting

confidence: 57%

“…Only more recently, various investigations have been directed towards TMDs with large mass ratios, also called nonconventional TMDs, given the growing interest in innovative applications such as mega-sub-control-structures (MSCS), inter-storey isolation systems and sliding roof systems (e.g. [21]). These TMDs have shown greater robustness than those with low mass ratios, due to their lower sensitivity to tuning (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…[28] provided the equations for optimal TMD tuning, using a 2 DOF reducedorder model without damping in the main structure, minimizing (i) the maximum amplitudes of the base shear force under harmonic excitations, or (ii) the variance of the base shear force under a band-limited random excitation of white noise. [21], similarly to [25], proposed a TMD optimization approach that approximately equals the damping ratios of the 2 DOF system and, at the same time, minimizes its overall response; in particular, in addition to minimizing the FRF of the displacement of the primary structure, as done by [25], [21] simultaneously minimized the FRF of the acceleration of the nonconventional TMD, holding the latter also structural functions.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Investigations on Inter-Storey Seismic Isolation as a Technique for Adding Upper Storeys

Bernardi¹,

Donà²,

Porto³

et al. 2021

Proceedings of the 8th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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The inter-storey seismic isolation technique is becoming increasingly attractive for the seismic risk mitigation of buildings, also as alternative strategy to base isolation. The reasons for applying this technique can be various and of different nature, such as: architectural concerns, feasibility of construction, and performance benefits. An interesting application of this technique concerns its use for adding upper storeys to existing buildings, avoiding the increase of seismic forces on the substructure, or even reducing them. Therefore, this technique could also be effective for seismic retrofit applications, using the mass of the superstructure as a nonconventional TMD for controlling the dynamic response of the substructure. Among the main issues concerning this application, there is the need to control the relative displacement between the two structural parts and the acceleration of the superstructure, while improving the seismic performance of the substructure. In this paper, a multi-objective optimization method for the dynamic characteristics of the additional superstructure is presented, which uses a TMD approach and considers the performances of the substructure, isolation system and superstructure. A 3-storey (3 DOF) case study structure was taken as a reference, analysing a wide range of isolated masses, isolation periods and damping ratios. Time-history analyses are finally performed, based on the optimization results, in order to assess the effectiveness of both the optimization method and the isolation technique, also considering the structural non-linearity.

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“…However, as discussed in previous study (e.g. [25,27,21]), reasonable variations of ξSDOF do not significantly affect the optimal TMD parameters.…”

Section: Comparison With Other Literature Solutionssupporting

confidence: 57%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Investigations on Inter-Storey Seismic Isolation as a Technique for Adding Upper Storeys

Bernardi¹,

Donà²,

Porto³

et al. 2021

Proceedings of the 8th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

View full text Add to dashboard Cite

show abstract

“…Various methods of TMD optimization are currently available, which differ mainly in the pursuit of different objective functions. Some of these maximize the effect of TMD (e.g., Sadek, 1997) or the energy dissipated by it (e.g., Reggio and De Angelis 2015); others minimize a certain structural response (e.g., Moutinho 2012;Zhou et al, 2016;Pietrosanti et al, 2017) or functions that take into account multi structural responses (e.g., Yahyai et al, 2019); still, some rely on multi-objective approaches to minimize primary structure response while controlling isolation drift or acceleration (e.g., Bernardi et al, 2021).…”

Section: Optimization Proceduresmentioning

confidence: 99%

Effectiveness of load-level isolation system for pallet racking systems

Donà

Bernardi

Zonta

et al. 2022

Front. Built Environ.

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Recent Italian earthquakes have shown the high seismic vulnerability of pallet racking systems. In the down-aisle direction and in the absence of bracing systems, these structures are very flexible moment-resisting frames. Instead, in the cross-aisle direction they consist of slender trusses, stiffened by various bracing systems; the latter, although necessary for lateral stability, attract significant seismic accelerations, which can cause the stored goods to fall, posing a threat to human safety. To reduce this risk while increasing the rack structural performance, some mitigation systems were proposed, based on specific base-isolation or dissipation devices. In this paper, an innovative passive control system is investigated, i.e., the Load-Level Isolation System (LLIS), which consists of applying isolators to the load level to control the movement of pallets in the cross-aisle direction. The LLIS is based on the Tuned Mass Damper (TMD) strategy and exploits the high payload of these structures. Among the major uncertainties of this system are the amount of isolated mass and its position within the structure. Therefore, for a case study rack, the LLIS parameters (isolation stiffness and damping ratio) are optimized for various arrangements of this system, considering cases with one or two isolated levels. The applied optimization procedure is an extension of the classical TMD approaches. The effectiveness of the optimized LLISs is then investigated through bidirectional Time-History analyses on 3D Finite Element rack models. The results show that using the LLIS, even on a single load-level, can greatly reduce the upright stresses and the cross-aisle displacements and accelerations, and that the optimal position of the LLIS is in the upper part of the rack.

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“…[9] However, Dai et al [10] recently pointed out that in a large mass ratio TMD with viscous dampers, the frequency dependence effect of the rubber bearings plays an important role in the seismic control performance. Yahyai et al [8] modified the equal-modal-damping optimization method and notably mitigated both the displacement and acceleration responses of the structures using a large-mass-ratio TMD.…”

mentioning

confidence: 99%

Cross‐level fragility analysis of modularized suspended buildings based on experimentally validated numerical models

Shafieezadeh

Sezen

et al. 2020

Structural Design Tall Build

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Summary Suspended buildings typically have a core as the primary and suspended floors as the secondary structures. These configurations offer visual transparency, smaller vertical components, and seismic attenuation via the primary–secondary structure interaction. Such attenuation is further enhanced by the modularization of the suspended segment which allows large drifts but prevents them from causing damage. Previously conducted shake‐table tests have confirmed these features. However, how the component performance contributes to system performance has not been quantitated. To address this gap, fragility analyses are conducted for 10‐story experimentally validated models with optimized supplemental dampers and inter‐module stiffness. Multiple limit state functions are proposed to provide a full account of damage sources. Additionally, a mapping rule from the component‐level to the system‐level limit states is developed which captures the influence of damage distribution on system‐level limit states. Results for the uncontrolled suspended building indicate that for the PGV of 0.5 m/s, the failure probabilities of the repairable and life safety limit states are 97% and 83%, respectively. These probabilities are 92% and 27% for the frame structure with viscous dampers, 58% and 5% for the passive‐controlled modularized suspended building system (MSBS), and 45% and 3% for MSBS with optimal vertical distributions of modularized secondary structure.

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Optimum Parameters for Large Mass Ratio TMDs Using Frequency Response Function

Cited by 15 publications

References 22 publications

Investigations on Inter-Storey Seismic Isolation as a Technique for Adding Upper Storeys

Investigations on Inter-Storey Seismic Isolation as a Technique for Adding Upper Storeys

Effectiveness of load-level isolation system for pallet racking systems

Cross‐level fragility analysis of modularized suspended buildings based on experimentally validated numerical models

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