The Prediction for Seismic Responses of the Two-Mass Model With the Mid-Story Isolation System

Murakami, Katsuhide; Kitamura, Haruyuki; Matsushima, Yuji

doi:10.3130/aijs.66.51_7

Cited by 18 publications

(12 citation statements)

References 1 publication

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“…A reduced‐order two‐DOF model, given by the two coupled oscillators in Figure (b), is introduced to design purposes ; the L portion of the frame structure is represented by the primary oscillator, with mass, stiffness, and damping coefficients equal to m 1 , k 1 , and c 1 , while the U portion is represented by the secondary oscillator, with mass, stiffness, and damping coefficients equal to m 2 , k 2 , and c 2 . In Table , it is shown how to relate the dynamic properties and response quantities of the reduced‐order two‐DOF model to those of the N ‐DOF structure.…”

Section: Energy‐based Design Of Inter‐story Isolationmentioning

confidence: 99%

Optimal energy‐based seismic design of non‐conventional Tuned Mass Damper (TMD) implemented via inter‐story isolation

Reggio

Angelis

2015

Earthq Engng Struct Dyn

141

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SummaryInter‐story isolation, an effective strategy for mitigating the seismic risk of both new and existing buildings, has gained more and more interest in recent years as alternative to base isolation, whenever the latter results to be impractical, technically difficult or uneconomic. As suggested by the name, the technique consists in inserting flexible isolators at floor levels other than the base along the height of a multi‐story building, thus realizing a non‐conventional Tuned Mass Damper (TMD). Consistent with this, an optimal design methodology is developed in the present paper with the objective of achieving the global protection of both the structural portions separated by the inter‐story isolation system, that is, the lower portion (below the isolation system) and the isolated upper portion (above the isolation system). The optimization procedure is formulated on the basis of an energy performance criterion that consists in maximizing the ratio between the energy dissipated in the isolation system and the input energy globally transferred to the entire structure. Numerical simulations, performed under natural accelerograms with different frequency content and considering increasing isolation levels along the height of a reference frame structure, are used to investigate the seismic performance of the optimized inter‐story isolation systems. Copyright © 2015 John Wiley & Sons, Ltd.

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Section: Energy‐based Design Of Inter‐story Isolationmentioning

confidence: 99%

Optimal energy‐based seismic design of non‐conventional Tuned Mass Damper (TMD) implemented via inter‐story isolation

Reggio

Angelis

2015

Earthq Engng Struct Dyn

141

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“…Apparently, MCE will occur if Equations (11) or (12) is satisfied. These two equations can be rewritten in the standard forms of hyperbolas as given in Equations (13) and (14), respectively…”

Section: Coupling Of Higher Modes Because Of Improper Design Of Substmentioning

confidence: 99%

“…The previous analytical studies disclosed that the contribution of higher modes might not be negligible in the midstory isolation design [12][13][14][15]. It is worth noting that the seismic responses at the super-floor and superstructure were enlarged because of the closeness of two higher modal frequencies that possess higher modal participation mass ratios.…”

mentioning

confidence: 99%

Analytical and experimental studies on midstory isolated buildings with modal coupling effect

Wang

Hwang

Chang

et al. 2012

Earthq Engng Struct Dyn

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SUMMARY In a midstory isolated building, the isolation system is incorporated into the midstory rather than the base of the building. Because of the flexibility of the substructure below the isolation system in a midstory isolated building, the contribution of higher modes to the seismic responses of the midstory isolated structure may not be negligible, especially when the coupling of higher modes exists. To investigate this modal coupling effect, a simplified three‐lumped‐mass structural model of the midstory isolated building is assumed in this study. Through the equivalent linear analysis and shaking table tests, it is found that the coupling of higher modes may lead to enlarged acceleration responses at the super‐floor and superstructure above the isolation layer. Accordingly, a simple method to prevent the midstory isolation design from the coupling of higher modes attributed to the improper design of the substructure and superstructure is proposed in this paper. Copyright © 2012 John Wiley & Sons, Ltd.

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“…In addition, a mid-storey-isolation system [1][2][3][4][5][6][7][8][9] has been devised, and there exist practical examples. However, a design scheme which considers both structural deformation and acceleration response has not been proposed so far.…”

Section: Introductionmentioning

confidence: 99%

Optimal stiffness distribution of mid-storeyisolated buildings considering storey drift and floor acceleration response

Kohiyama¹,

Takano²

2013

WIT Transactions on the Built Environment

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This paper formulates a response prediction formula based on complex modal superposition and frequency response functions of single-degree-of-freedom systems for both storey drift and floor acceleration of a mid-storey-isolated building under the assumption of white noise input. This study verifies that the proposed formula can estimate the seismic response of a building accurately, even if a system includes the overdamped mode, by comparing the same with the results of a time-history analysis. To support the structural design of a midstorey-isolated building, the proposed formula is applied to an optimal design problem, which considers the objective function of acceleration response in a superstructure and constraints on storey drifts. A genetic algorithm is employed to obtain the optimal stiffness distribution and damping coefficient of the isolation layer. This study confirms that the acceleration response of the optimal design is successfully reduced, with other responses remaining within acceptable ranges.

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The Prediction for Seismic Responses of the Two-Mass Model With the Mid-Story Isolation System

Cited by 18 publications

References 1 publication

Optimal energy‐based seismic design of non‐conventional Tuned Mass Damper (TMD) implemented via inter‐story isolation

Optimal energy‐based seismic design of non‐conventional Tuned Mass Damper (TMD) implemented via inter‐story isolation

Analytical and experimental studies on midstory isolated buildings with modal coupling effect

Optimal stiffness distribution of mid-storeyisolated buildings considering storey drift and floor acceleration response

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