• 한국구조물진단유지관리공학회 논문집
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• 제18권5호
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• pp.107-115
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• 2014

본 연구에서는 건물의 질량중심과 면진층의 강성중심 사이의 차이에 따른 면진효과에 대하여 살펴보았다. 면진기술은 면진층에 설치되는 면진장치의 성능에 크게 의존하는 기술이므로 면진장치 제작 후 전수검사를 통하여 면진장치의 수평강성을 검토하게 되어 있다. 하지만 면진장치 성능실험 시 각각의 면진장치의 품질기준은 건축기준에는 정해져 있지 않으며, 이로 인해 설계 시 적용된 강성과 실제 강성의 차이가 발생하여 면진층 상부 부재에 큰 문제를 야기할 수 있다. 연구결과, 최대응답변위의 차이는 크게 나타나지 않았으나 편심이 증가할수록 최대응답가속도, 층전단력 및 상부구조의 부재력은 크게 증가하여 일부 부재에서는 과도한 손상이 예상된다. 따라서 면진층은 실제 장치 제작 후 전수검사를 실시하여 반드시 설계된 의도대로 편심이 발생하지 않도록 장치를 재배치할 필요가 있으며, 가능하다면 건물의 질량중심과 강성중심의 차이는 동일하게 설계할 것을 추천한다.

• 한국공간구조학회논문집
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• 제18권1호
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• pp.109-116
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• 2018

As the number of high-rise buildings increases, a mid-story isolation system has been proposed for high-rise buildings. Due to structural problems, an appropriate isolation layer displacement is required for an isolation system. In this study, the mid-story isolation system was designed and the seismic response of the structure was investigated by varying the yield strength and the horizontal stiffness of the seismic isolation system. To do this, a model with an isolation layer at the bottom of $15^{th}$ floor of a 20-story building was used as an example structure. Kobe(1995) and Nihonkai-Chubu(1983) earthquake are used as earthquake excitations. The yield strength and the horizontal stiffness of the seismic isolation system were varied to determine the seismic displacement and the story drift ratio of the structure. Based on the analytical results, as the yield strength and horizontal stiffness increase, the displacement of the isolation layer decreases. The story drift ratio decreases and then increases. The displacement of the isolation layer and the story drift ratio are inversely proportional. Increasing the displacement of the isolation layer to reduce the story drift ratio can cause the structure to become unstable. Therefore, an engineer should choose the appropriate yield strength and horizontal stiffness in consideration of the safety and efficiency of the structure when a mid-story isolation system for a high-rise building is designed.

• 대한건축학회논문집:구조계
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• 제35권8호
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• pp.149-156
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• 2019

In this study, dynamic responses of high - rise buildings were analyzed through the change of horizontal stiffness and yield strength among characteristics of seismic isolation system by applying middle - layer seismic isolation system to high - rise buildings of 120m height. As a result in order to prevent the displacement of the isolation layer and to control the maximum torsion angle, it is possible to appropriately control by increasing or decreasing the horizontal stiffness and the yield strength. However, depending on the maximum torsional angle and the hysteretic behavior of the seismic isolation system, excessive yield strength and horizontal stiffness increase may induce the elastic behavior of the structure and amplify the response. Therefore, it is considered that it is necessary to select the property value of the appropriate isolation device.

• Earthquakes and Structures
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• 제26권1호
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• pp.1-15
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• 2024

Isolation technology has been proven effective in reducing the seismic response of superstructures, where most of the deformation is concentrated in the isolation layer. However, in cases of earthquakes with intensities surpassing the fortification level of the area, or severe near-fault earthquakes, the isolation layer may experience excessive deformation, resulting in damage to the isolation bearings or collisions with the retaining wall or surrounding buildings. In this study, a finite element model using ABAQUS is established and compared with experimental test results to deeply investigate the influence of limit devices on the isolation layer and its response to the superstructure. The findings reveal that a larger limiter stiffness and a smaller reserved gap can achieve a more effective limiting effect. Nevertheless, a smaller reserved gap and a larger limiter stiffness may result in increased response of the superstructure. Therefore, rational selection of the reserved gap and limiter stiffness is crucial to reduce the acceleration response.

• 한국구조물진단유지관리공학회 논문집
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• 제14권6호
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• pp.93-99
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• 2010

본 논문에서는 상부구조에 있어서 보-기둥 강성비 변화에 따른 골조의 특성과 상부구조와 면진층 간의 진동주기비에 따른 면진효과를 분석해 보고, 상부골조의 주기와 목표 면진주기의 설정에 따라 면진효과가 어떻게 달라지는가에 대한 정보를 제공하여 향후 면진건물을 설계하기 위한 기본계획을 세우는데 있어서 필요한 기초 자료를 제공하고자 한다. 그 결과 건물골조의 경우 유효한 면진효과를 얻기 위해서는 최소한 상부구조의 고유진동주기 대비 2.5배 이상의 면진주기를 확보하고, 목표 면진주기를 2.0초 이상으로 설정하여 설계할 것을 추천한다.

• International Journal of Concrete Structures and Materials
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• 제9권4호
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• pp.439-451
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• 2015

This study analyzed the isolation effect for a 15-story reinforced concrete (RC) building with regard to changes in the beam-column stiffness ratio and the difference in the vibration period between the superstructure and an isolation layer in order to provide basic data that are needed to devise a framework for the design of isolated RC buildings. First, this analytical study proposes to design RC building frames by securing an isolation period that is at least 2.5 times longer than the natural vibration period of a superstructure and configuring a target isolation period that is 3.0 s or longer. To verify the proposed plan, shaking table tests were conducted on a scaled-down model of 15-story RC building installed with laminated rubber bearings. The experimental results indicate that the tested isolated structure, which complied with the proposed conditions, exhibited an almost constant response distribution, verifying that the behavior of the structure improved in terms of usability. The RC building's response to inter-story drift (which causes structural damage) was reduced by about one-third that of a non-isolated structure, thereby confirming that the safety of such a superstructure can be achieved through the building's improved seismic performance.

• KIEAE Journal
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• 제12권1호
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• pp.73-81
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• 2012

Floor impact sound has been most annoying for years among the noises which are produced in apartment. This study aims to analyze the improvement of floor impact sound by comparing the results of the test which was carried out for the wall slab type apartment and moment frame apartment, and also for the effect of advanced vibration isolation layer. Moment frame structure that main structure consists of column and slab has shown better performance for the heavyweight impact sound comparing with wall slab type structure which is general type in Korea. Stiffness of floor system was raised by reinforcing the stiffness of vibration isolation layer, and it was analyzed how much the floor impact sound performance was improved. The result showed that the reinforced floor had better performance than the existing floor system that uses lightweight porous concrete as vibration isolation material. In addition, a system used wire mesh in mortar showed improvement of floor impact sound than a system without wire mesh, and better performance for the frequency bands lower than 160 Hz which causes floor impact problem in wall slab type apartment.

• Structural Engineering and Mechanics
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• 제48권4호
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• pp.479-500
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• 2013

This paper presents the experimental as well as analytical study conducted on layer-bonded scrap tire rubber pad (STRP) isolators to develop low-cost seismic isolators applicable to structures in developing countries. The STRP specimen samples were produced by stacking the STRP layers one on top of another with the application of adhesive. In unbonded application, the STRP bearings were placed between the substructure and superstructure without fastening between the contact surfaces which allows roll-off of the contact supports. The vertical compression and horizontal shear tests were conducted with varying axial loads. These results were used to compute the different mechanical properties of the STRP isolators including vertical stiffness, horizontal effective stiffness, average horizontal stiffness and effective damping ratios. The load-displacement relationships of STRP isolators obtained by experimental and finite element analysis results were found to be in close agreement. The tested STRP samples show energy dissipation capacity considerably greater than the natural rubber bearings. The layer-bonded STRP isolators serve positive incremental force resisting capacity up to the shear strain level of 150%.

• Earthquakes and Structures
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• 제22권1호
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• pp.53-64
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• 2022

This study proposes an intelligent semi-active isolation system combining a variable-stiffness control device and ground motion characteristic prediction. To determine the optimal control parameter in real-time, a genetic algorithm (GA)-fuzzy control law was developed in this study. Data on various types of ground motions were collected, and the ground motion characteristics were quantified to derive a near-fault (NF) characteristic ratio by employing an on-site earthquake early warning system. On the basis of the peak ground acceleration (PGA) and the derived NF ratio, a fuzzy inference system (FIS) was developed. The control parameters were optimized using a GA. To support continuity under near-fault and far-field ground motions, the optimal control parameter was linked with the predicted PGA and NF ratio through the FIS. The GA-fuzzy law was then compared with other control laws to verify its effectiveness. The results revealed that the GA-fuzzy control law could reliably predict different ground motion characteristics for real-time control because of the high sensitivity of its control parameter to the ground motion characteristics. Even under near-fault and far-field ground motions, the GA-fuzzy control law outperformed the FPEEA control law in terms of controlling the isolation layer displacement and the superstructure acceleration.

• Structural Engineering and Mechanics
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• 제48권6호
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• pp.809-822
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• 2013

Base isolation is widely used in seismic resisting buildings due to its low construction cost, high reliability, mature theory and convenient usage. However, it is difficult to design the isolation layer in high-rise buildings using the available bearings because high-rise buildings are characterized with long period, low horizontal stiffness, and complex re-distribution of the internal forces under earthquake loads etc. In this paper, a simple and innovative isolation bearing, named Teflon-based lead rubber isolation bearing, is developed to address the mentioned problems. The Teflon-based lead rubber isolation bearing consists of friction material and lead rubber isolation bearing. Hence, it integrates advantages of friction bearings and lead rubber isolation bearings so that improves the stability of base isolation system. An experimental study was conducted to validate the effectiveness of this new bearing. The effects of vertical loading, displacement amplitude and loading frequency on the force-displacement relationship and energy dissipation capacity of the Teflon-based lead rubber isolation bearing were studied. An analytical model was also proposed to predict the force-displacement relationship of the new bearing. Comparison of analytical and experimental results showed that the analytical model can accurately predict the force-displacement relationship and elastic shear deflection of the Teflon-based lead rubber isolation bearings.