Model reduction and optimal parameters of mid-story isolation systems

Zhou, Qi; Singh, M. P.; Huang, Xing

doi:10.1016/j.engstruct.2016.06.011

Cited by 39 publications

(18 citation statements)

References 11 publications

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“…The research was conducted by reviewing several alternative locations for story isolation, and it was found that for systems with a single-story isolator, the effectiveness of using the isolator decreases with increasing isolator locations, or in other words, the best location for story isolator is between level 1 and level 2. Zhou et al, in 2016, simplified the building model with story isolators and obtained the optimum parameters of the isolator used. In the example section of numerical calculations for a 16-story building, it is found that the smallest level of roof deformation and shear forces are experienced by structures that are isolated at the lower level.…”

Section: *Corresponding Authormentioning

confidence: 99%

Optimum Location Analysis of Story Isolation System on High Rise Building

Reza

Setio

2021

JTS ITB

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Various studies have been carried out to evaluate the feasibility and effectiveness of the story isolation system. The results obtained are also quite impressive, where the story isolation system gave a better story drift reduction than the base isolation system. However, these studies only focused on low-rise buildings, even though the story isolation system will be more engaging if it could also be compatible with high-rise buildings. In this study, a numerical analysis will be carried out on 30-, 40-, 50-, and 60-story buildings to evaluate the story isolator’s location, so that the system gives an optimum reduction of story drift and story shear. Then a general solution is sought to become a reference for buildings with different plans and heights. Keywords: Story isolation system, story isolator optimum location, high-rise building. Abstract Berbagai penelitian telah dilakukan untuk mengevaluasi kelayakan dan efektivitas sistem isolasi tingkat. Hasil yang diperoleh juga cukup mengesankan, dimana sistem isolasi tingkat memberikan reduksi simpangan antar tingkat yang lebih baik dibandingkan dengan sistem isolasi dasar. Namun, studi tersebut hanya berfokus pada bangunan bertingkat rendah, padahal sistem isolasi lantai akan lebih menarik jika dapat juga digunakan pada bangunan bertingkat tinggi. Dalam studi ini, analisis numerik akan dilakukan pada bangunan berlantai 30, 40, 50, dan 60 untuk mengevaluasi lokasi isolator tingkat yang memberikan reduksi simpangan tingkat dan geser tingkat terbesar. Kemudian dicari solusi umum untuk menjadi acuan untuk bangunan dengan denah dan ketinggian yang berbeda. Kata kunci: Sistem isolasi tingkat, lokasi optimum isolator tingkat, bangunan bertingkat tinggi.

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Section: *Corresponding Authormentioning

confidence: 99%

Optimum Location Analysis of Story Isolation System on High Rise Building

Reza

Setio

2021

JTS ITB

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“…This isolation strategy basically converts the mass of the isolated superstructure into a non-conventional tuned mass damper (Reggio and De Angelis 2015); therefore, the superstructure performs a dynamic control function in addition to the structural one. In general, it is possible to identify three behavioural categories-mass damping, intermediate isolation and base isolation-based on the mass ratio between the superstructure and substructure (Faiella and Mele 2019;Zhou et al 2016;Tan et al 2008).…”

Section: Introductionmentioning

confidence: 99%

“…Also, general studies on the optimisation of FVDs for such applications, addressed to their design, are missing. In fact, relevant studies in the literature mainly deal with the optimal arrangement of multiple isolation systems in buildings (Charmpis et al 2012;Charmpis et al 2015) and the optimal values of the isolator parameters (Reggio et al 2015;Zhou et al 2016). As for FVDs, many optimisation strategies are available for traditional applications in frames (e.g., see De Domenico et al 2019), whereas only a few studies in the field of bridges deal with the optimisation of FVDs used together with isolators, focussing on linear dampers (Xie et al 2017).…”

Section: Introductionmentioning

confidence: 99%

Evaluation of optimal FVDs for inter-storey isolation systems based on surrogate performance models

Donà

Bernardi

Zonta

et al. 2021

Bull Earthquake Eng

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Inter-storey seismic isolation is increasingly gaining attention. One of the main related issues is the need to limit the relative displacement between substructure and superstructure, while maintaining a good seismic performance of the superstructure. As shown in some studies, fluid viscous dampers (FVDs) mounted in isolation systems are effective in reducing isolator deflection but can be harmful by amplifying inter-storey drifts and floor accelerations. Additionally, the effectiveness of FVDs for inter-storey applications was investigated only recently, and specific approaches for their optimisation and performance evaluation are missing. Therefore, this paper proposes a method for the optimal multi-objective design of FVDs, based on the definition of appropriate surrogate response models, which allows for rationally comparing the FVD effects for a wide range of dampers and structures. In particular, the optimal FVD parameters are provided in a dimensionless form, so that they can be predicted by design equations of general validity within the range of the structures analysed. This method is applied to a stock of regular structures with various vibration periods of superstructure, isolation and substructure, examining a linear and a non-linear isolation system and a set of natural records, in order to comprehensively assess the effects of FVDs and their non-linearity on the seismic performance of these structures. Finally, prediction models of optimal FVD parameters are provided based on the results obtained and are applied to three case studies as an example.

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“…[27] compared different optimization approaches, minimizing the variance of the responses (i) in displacement or (ii) in acceleration of the primary structure, or (iii) maximizing the energy dissipated by the TMD system (like [26]). [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%

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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Model reduction and optimal parameters of mid-story isolation systems

Cited by 39 publications

References 11 publications

Optimum Location Analysis of Story Isolation System on High Rise Building

Optimum Location Analysis of Story Isolation System on High Rise Building

Evaluation of optimal FVDs for inter-storey isolation systems based on surrogate performance models

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

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