Torsional Response Induced by Lateral Displacement and Inertial Force

Kohiyama, Masayuki; Yokoyama, H.

doi:10.3389/fbuil.2018.00038

Cited by 12 publications

(16 citation statements)

References 30 publications

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“…20,21 In addition, the authors found that torsional vibration occurs in bisymmetric buildings owing to horizontal displacements; this is called the "Q-Δ effect." 22,23 In particular, torsional resonance occurs when the torsional natural circular frequency becomes the sum or difference of the two translational natural circular frequencies, and the torsional response increases. This resonance is termed "Q-Δ resonance" and is categorized as autoparametric resonance.…”

Section: Introductionmentioning

confidence: 99%

Torsional response of a bisymmetric structure induced by bending–torsion interaction in vertical members

Kohiyama

Yokoyama

Maki

2021

Japan Architectural Review

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The biaxially symmetric column induces torsional moment owing to the bendingtorsion interaction when the top of the column is given horizontal displacement in the two directions of the principal axes of the cross section and the rotation of the column ends around the axes is constrained. Hence, horizontal ground motions in two directions can cause non-negligible torsional vibration in a highrise building owing to autoparametric resonance. To investigate this phenomenon, in this study, we focus on a single-story structure with an aggregated column, which is a model for columns or core structures in tall buildings and is assumed to be an elastic Euler beam; subsequently we derive the equations of motion under horizontal ground motions in two directions. The resonance condition in the torsional direction is also investigated. Time-series response analyses are performed for input ground motions of harmonic waves, white noise, acceleration records of prior earthquakes, and a long-period design wave, and the relationship between the ratio of two translational natural frequencies and the increase in maximum responses is explained. The results demonstrate that the absolute acceleration response to the long-period design wave could increase by more than 50% in the worst-case scenario.

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Section: Introductionmentioning

confidence: 99%

Torsional response of a bisymmetric structure induced by bending–torsion interaction in vertical members

Kohiyama

Yokoyama

Maki

2021

Japan Architectural Review

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“…The method to derive the resonance condition is based on the existing literature. [ 12 ] An elastic Euler beam is considered. The restoring force of the column is considered up to the second‐order term that is related to the Q–Δ resonance, which takes into account the geometric nonlinearity.…”

Section: Equations Of Motionmentioning

confidence: 99%

“…Model 0 is the same model that was used in Kohiyama and Yokoyama. [ 12 ] It assumed that the column was modeled as a linear spring, and we used a coefficient of 1/2 for a torque term due to the bending–torsion interaction in consideration of the distribution of the torsional moment, as follows.

m \overset{x}{true} + c_{x} \overset{x}{true} + k_{x} x = - m {\ddot{x}}_{0},

m \overset{y}{true} + c_{y} \overset{y}{true} + k_{y} y = - m {\ddot{y}}_{0},

I \overset{θ}{true} + c_{θ} \overset{θ}{true} + k_{θ} θ = - \frac{1}{2} ((), c_{x} \overset{x}{true} y - c_{y} \overset{y}{true} x) - \frac{1}{2} ((), k_{x} - k_{y}) italicxy,

…”

Section: Shaking Table Test With Double Sine Wave Inputmentioning

confidence: 99%

“…By replacing the vertical load P with the horizontal restoring force Q , the resulting torsional moment induces a torsional response, even in a symmetric structure with no eccentricity. [ 11,12 ] Hong [ 11 ] termed this phenomenon the A – Δ effect focusing on (additional) instantaneous load eccentricities and noted that the seismic displacement demand is underestimated if this effect is ignored. Kohiyama and Yokoyama [ 12 ] independently termed this phenomenon the Q – Δ effect and found the condition to induce a significant torsional response that the natural frequency of a torsional mode is identical to the sum or difference of the natural frequencies of translational modes in the x and y directions.…”

Section: Introductionmentioning

confidence: 99%

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Experiment of torsional response induced by the Q–delta resonance

Mizutori

Kohiyama

2020

Structural Design Tall Build

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Summary Because of geometric nonlinearities, vibrations in two horizontal directions can generate a torsional moment that induces a torsional response, even in a structure with no eccentricity; we term this phenomenon Q–Δ effect. In this study, the torsional response caused by the Q–Δ resonance was investigated by performing a shaking table test that involves a single‐layer symmetric specimen. The specimen was designed and fabricated by focusing on one of two resonance conditions. Its moment of inertia was adjustable by changing locations of weights, and the natural frequency in the torsional mode could be modified. We developed a numerical model of the specimen, in which the columns connected to the slab were integrated into an elastic Euler beam. It was confirmed that the torsional response increased near the predicted Q–Δ resonance point. In addition, the acceleration at the corner of the slab was significantly increased. The formulated equations of motion provided a better prediction of the actual phenomena. Because the specimen corresponds to a stiff and slender high‐rise building when converted into a full scale, the result suggests a need to be aware of the risk of torsional response increase due to the Q–Δ resonance.

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“…Furthermore, the structural system of modern high‐rise buildings is often irregular with considerable eccentricities between the mass and stiffness centers . Even for the buildings with a symmetric plan in design, their real structural system may be asymmetric to some degree due to uncertainties in construction and occupancy.…”

Section: Introductionmentioning

confidence: 99%

Optimal multi‐type sensor placement for monitoring high‐rise buildings under bidirectional long‐period ground motions

Zhao

2020

Struct Control Health Monit

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Summary Towards a complete and accurate seismic assessment of a super high‐rise building under bidirectional long‐period ground motions, this study proposes an optimal multi‐type sensor placement framework for the best reconstruction of structural responses and ground motions based on a full‐scale 3D finite element (FE) model of the building. The selected locations and types of sensors are capable of not only capturing the coupled bending‐torsional vibration but also providing an unbiased estimation of the unmeasured responses of seismic‐vulnerable components and bidirectional ground motions. A Kalman filtering algorithm‐based data fusion technique is employed to deal with the measurement data from multi‐type sensors. With the target of achieving the best reconstruction, an optimal sensor placement (OSP) configuration, which minimizes the reconstruction error, is achieved through a sequential sensor placement algorithm. To assess the feasibility of the proposed OSP framework and the accuracy of reconstructed responses and ground motions, a numerical study is also performed on the full‐scale 3D FE model of a super high‐rise building. The torsional effects of the building under bidirectional long‐period ground motions are assessed by comparison with the results without considering the torsional effect. The numerical results show that the proposed framework is feasible and the reconstructed responses and ground motions are accurate and that the torsional effects cannot be neglected in the seismic assessment of the building.

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Torsional Response Induced by Lateral Displacement and Inertial Force

Cited by 12 publications

References 30 publications

Torsional response of a bisymmetric structure induced by bending–torsion interaction in vertical members

Torsional response of a bisymmetric structure induced by bending–torsion interaction in vertical members

Experiment of torsional response induced by the Q–delta resonance

Optimal multi‐type sensor placement for monitoring high‐rise buildings under bidirectional long‐period ground motions

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