• Smart Structures and Systems
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• v.16 no.6
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• pp.981-1002
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• 2015

For vibration control of civil structures, especially large civil structures, one of the important issues is how to place a minimal number of actuators and sensors at their respective optimal locations to achieve the predetermined control performance. In this paper, a methodology is presented for the determination of the minimal number and optimal location of actuators and sensors for vibration control of building structures under earthquake excitation. In the proposed methodology, the number and location of the actuators are first determined in terms of the sequence of performance index increments and the predetermined control performance. A multi-scale response reconstruction method is then extended to the controlled building structure for the determination of the minimal number and optimal placement of sensors with the objective that the reconstructed structural responses can be used as feedbacks for the vibration control while the predetermined control performance can be maintained. The feasibility and accuracy of the proposed methodology are finally investigated numerically through a 20-story shear building structure under the El-Centro ground excitation and the Kobe ground excitation. The numerical results show that with the limited number of sensors and actuators at their optimal locations, the predetermined control performance of the building structure can be achieved.

• International Journal of High-Rise Buildings
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• v.3 no.1
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• pp.49-64
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• 2014

Natural vibration period is an important parameter for high-rise building, Based on 414 high-rise buildings completed or passed over-limit approval in China, the distribution law of natural vibration periods is analyzied. In order to satisfy the design requirements, such as global stability, story drift limit and minimum shear-gravity ratio, the reference ranges of fundamental periods $T_1$ are $0.3{\sqrt{H}}{\sim}0.4{\sqrt{H}}$ when the structural heights $H{\geq}250m$, when 150 m ${\leq}$ H < 250m, $T_1=0.25{\sqrt{H}}{\sim}0.4{\sqrt{H}}$, when 100 m ${\leq}$ H < 150 m, $T_1=0.2{\sqrt{H}}{\sim}0.35{\sqrt{H}}$, when 50 m $ {\leq}$ H < 100m, $T_1=0.15{\sqrt{H}}{\sim}0.3{\sqrt{H}}$. These can provide reference data for controlling mass and rigidity of high-rise buildings.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.432-441
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• 2008

In this study, the control performance of a Tuned Liquid Mass Damper(TLMD) manufactured to reduce the orthogonal bi-directional responses of building structures was experimentally evaluated. the TLMD using only one control device reduce bi-directional responses of building structures by making the TLMD behave as TMD and TLCD to the strong and weak axial direction of building structures. first, the control performance was evaluated by forcing sinusoidal waves to a test model that the TLMD is installed on the scale-downed building structure. Second, the real-time hybrid shaking table test was performed to evaluate the performance of the vibration control system made up of numerical part as a scale-downed building structural model and a physical experimental part as a TLMD. the superiority of bi-directional vibration control performance of the manufactured TLMD was verified by comparing the uncontrolled and controlled results of these tests.

• Steel and Composite Structures
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• v.22 no.3
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• pp.647-662
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• 2016

This study aims to monitor the variation of modal frequencies of steel buildings during their construction sequence. In this respect, construction of a steel building is followed by vibration based measurements. The monitored building is a three-story educational building within a building group whose structural system consists of steel moment resisting steel frames and eccentric braces. Five different acceleration measurements in two perpendicular directions are taken on five different construction stages, starting from the erection of the columns and beams ending with the completion of the construction. The recorded measurements are transferred into frequency domain and the dominant frequencies for each case have been determined. The change in the dominant frequencies is evaluated with the existing construction stages and performed constructional works between the stages. The last measurement, performed on the building in service, revealed the first two dominant frequencies as mutual in X and Y direction, showing that these dynamic modes are torsional modes. This result is investigated by numerical analysis performed with finite element model of the building constructed for design purpose. Lower frequencies and different mode shapes are determined from numerical analysis. The reason of lower frequencies is discussed and the vibration survey is extended to determine the effects of an adjacent building. The results showed that the building is in strong relation with an adjoining building in spite of a designed construction joint.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2004.05a
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• pp.27-32
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• 2004

Recently, the expansion of social infrastructures and urban redevelopment, the construction works have been a rapidly increase. The subway's noise and vibration are on a continuously increasing status in its importance as by the industrial and cultural development process. Nevertheless, in our country, adequate alternative idea for the construction noise and vibration are not yet established. In this point, the purpose of this study is to know the vibration effect to the structure. This study was used to determine the standard of vibration and the way of losing vibration. The case of construction site is a good example. The data of this study was obtained by a construction company in Korea. Vibration effect could cause structural problems and affect human mental state. The results of this study are as follows; check the vibrating point, determine the suitable limit of vibration, make a good plan and construction.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.982-987
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• 2002

Recently, as size of building structure becomes larger, mat area of building structure is supported on Inhomogeneous foundation. The equipment machineries in building are mostly on basement story. The slab of the lowest basement story with equipment machineries is considered as plate supported on foundation with concentrated masses. In this paper, vibration analysis of rectangular thin plate is done by use of rectangular finite element with 4 nodes. The solution of this paper are compared with existing solution and natural frequencies of thin plates, with concented mass, on inhomogeneous Pasternak foundation are calculated

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11a
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• pp.368.1-368
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• 2002

System Identification is carried out for a full scale five-story holing to design a vibration controller design. Dynamic characteristics such as natural frequencies, damping ratios, and modes are obtained from the input/output informal ion by both sine-sweet method and white noise method. The active mass driver installed on the third floor is applied as external loading to move the building and each floor acceleration is measured and processed for the system identification. (omitted)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.972-977
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• 2000

One of the major differences of Korean residential building compared with other countries is a rigid diaphragm of a floor due to the panel heating system. An increment of a gravity floor load might cause vibration problem when the composite floor system is introduced to the panel heating system. Since the noise criteria of a residential building is lower than that of an office building, the development of a noise absorbing system should be preceded. The response evaluation was performed for the finished floor, that is with panel heating and noise absorbing system. The natural frequency was obtained both from an experimental study and an analytical study. An appropriate vibration condition of a floor with panel heating and noise absorbing systems was evaluated from this study.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1095-1100
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• 2004

When the walls and floor of a tunnel are excited by a train, a ground vibration energy is transmitted to the surface and to footing of a nearby buildings. Excessive vibration affected to a building structures causes undesirable effect to the structural safety and the perception on residents in building. In this paper, a simple approach is introduced to predict how much vibration, in terms of level and spectra, is transmitted through the ground from the tunnel vibration excitation. A high rise building on a tunnel is selected as an application example of this case study.

• International Journal of High-Rise Buildings
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• v.11 no.3
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• pp.207-219
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• 2022

During the structural design of urban over-track high-rise buildings, two problems are most likely encountered: the abrupt change of story stiffness between the podium and the upper towers, as well as the demand for train-induced vibration control. Traditional earthquake-resistant structures have to be particularly designed with transfer stories to meet the requirement of seismic control under earthquakes, and thus horizontal seismic isolation techniques are recommended to solve the transfer problem. The function of mitigating the vertical subway-induced vibration can be integrated into the isolation system including thick rubber bearings and 3D composite vibration control devices. Engineering project cases are presented in this paper for a more comprehensive understanding of the engineering practice and research frontiers of urban over-track high-rise buildings in China.