• 한국공간구조학회논문집
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• 제10권3호
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• pp.49-56
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• 2010

본 연구에서는 스마트 최상층 면진시스템을 적용한 고층건물의 풍응답 제어성능을 검토해보았다. 이를 위하여 77층 초고층 건물을 예제구조물로 선택하였고 풍동실험을 통해서 얻은 풍하중을 사용하여 수치해석을 수행하였다. 예제구조물의 최상층은 FPS 및 MR 감쇠기로 구성된 스마트 면진시스템을 이용하여 주구조물과 분리된다. 주구조물의 동적응답을 저감시키는 것이 스마트 최상층 면진시스템의 가장 중요한 목표이지만 면진된 최상층의 과도한 응답은 구조물을 불안정하게 만들 수 있다. 따라서, 본 연구에서는 면진된 최상층과 주구조물을 효과적으로 제어하기 위하여 스카이훅제어기를 제어알고리즘으로 사용하였다. 제안된 스마트 최상층 면진시스템의 제어성능을 검토하기 위하여 일반적인 수동 최상층 면진시스템의 제어성능과 비교하였다. 수치해석결과 제안된 스마트 최상층 면진시스템을 이용하면 일반적인 수동 최상층 면진시스템에 비해서 면진층의 변위를 효과적으로 줄이면서도 구조물의 응답을 저감시킬 수 있음을 확인할 수 있었다.

• Wind and Structures
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• 제10권5호
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• pp.481-494
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• 2007

Downbursts are transient phenomena that produce wind profiles that are distinctly different from synoptic boundary layers. Wind field data from Computational Fluid Dynamics (CFD) simulations of isolated downburst-like impinging jets, are used to investigate structural loads of tall buildings due to these high intensity winds. The base shear forces and base moments of tall buildings of heights between 120 and 250 m produced by downburst winds of various scales are compared with the forces from the equivalent boundary layer gust winds, with matched 10-metre wind velocity. The wind profiles are mainly functions of the size of the downburst and the radial distance from the centre of the storm. Wind forces due to various downburst profiles are investigated by placing the building at different locations relative to the storm center as well as varying the size of the downburst. Overall it is found that downbursts larger than approx. 2,000 m in diameter might produce governing design wind loads above those from corresponding boundary layer winds for tall buildings.

• Earthquakes and Structures
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• 제18권6호
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• pp.667-675
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• 2020

The current study compares the effect of structure-soil-structure interaction (SSSI) on the dynamic responses of adjacent buildings and isolated structures including soil-structure interaction (SSI) with the responses of fixed-base structures. Structural responses such as the relative acceleration, displacement, drift and shear force were considered under earthquake ground motion excitation. For this purpose, 5-, 10- and 15-story structures with 2-bay moment resisting frames resting on shallow foundations were modeled as a group of buildings in soft soil media. Viscous lateral boundaries and interface elements were applied to the soil model to simulate semi-infinite soil media, frictional contact and probable slip under seismic excitation. The direct method was employed for fully nonlinear time-history dynamic analysis in OpenSees using 3D finite element soil-structure models with different building positions. The results showed that the responses of the grouped structures were strongly influenced by the adjacent structures. The responses were as much as 4 times greater for drift and 2.3 times greater for shear force than the responses of fixed-base models.

• 한국지진공학회논문집
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• 제17권2호
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• pp.53-59
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• 2013

Several researches have been studied to enhance the seismic performance of nuclear power plants (NPPs) by application of seismic isolation. If a seismic base isolation system is applied to NPPs, seismic performance of nuclear power plants should be reevaluated considering the soil-structure interaction effect. The seismic fragility analysis method has been used as a quantitative seismic safety evaluation method for the NPP structures and equipment. In this study, the seismic performance of an isolated NPP is evaluated by seismic fragility curves considering the soil-structure interaction effect. The designed seismic isolation is introduced to a containment building of Shin-Kori NPP which is KSNP (Korean Standard Nuclear Power Plant), to improve its seismic performance. The seismic analysis is performed considering the soil-structure interaction effect by using the linearized model of seismic isolation with SASSI (System for Analysis of Soil-Structure Interaction) program. Finally, the seismic fragility is evaluated based on soil-isolation-structure interaction analysis results.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2005년도 동계학술발표대회 논문집
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• pp.241-246
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• 2005

The objective of this study is to develop a rule-based fault detection and diagnosis algorithm and an experimental verification using air handling unit. To develop an analytical algorithm which precisely detects a faulted component, energy equations at each control volume of AHU were applied. An experimental verification was conducted in the AHU at Green Building in KIER. In the experiment conducted in hot summer condition, the rule based FDD algorithm isolated a faulted sensor from HVAC components.

• Structural Engineering and Mechanics
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• 제17권3_4호
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• pp.331-346
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• 2004

A new sensor system is proposed for measuring damage indexes. The damage index is a physical value that is well correlated to a critical damage in a device or a structure. The mechanism proposed here utilizes elastic buckling of a thin wire and does not require any external power supply for memorizing the index. The mechanisms to detect peak strain, peak displacement, peak acceleration and cumulative deformation as examples of damage indexes are presented. Furthermore, passive and active wireless data retrieval mechanisms using electromagnetic induction are proposed. The passive wireless system is achieved by forming a closed LC circuit to oscillate at its natural frequency. The active wireless sensor can transmit the data much further than the passive system at the sacrifice of slightly complicated electric circuit for the sensor. For wireless data retrieval, no wire is needed for the sensor to supply electrical power. For the active system, electrical power is supplied to the sensor by radio waves emitted from the retrieval system. Thus, external power supply is only needed for the retrieval system when the retrieval becomes necessary. Theoretical and experimental studies to show excellent performance of the proposed sensor are presented. Finally, a prototype damage index sensor installed into a 7 storey base-isolated building is explained.

• Smart Structures and Systems
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• 제4권6호
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• pp.795-807
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• 2008

A challenging problem in structural damage detection based on vibration data is the requirement of a large number of sensors and the numerical difficulty in obtaining reasonably accurate results when the system is large. To address this issue, the substructure identification approach may be used. Due to practical limitations, the response data are not available at all degrees of freedom of the structure and the external excitations may not be measured (or available). In this paper, an adaptive damage tracking technique, referred to as the sequential nonlinear least-square estimation with unknown inputs and unknown outputs (SNLSE-UI-UO) and the sub-structure approach are used to identify damages at critical locations (hot spots) of the complex structure. In our approach, only a limited number of response data are needed and the external excitations may not be measured, thus significantly reducing the number of sensors required and the corresponding computational efforts. The accuracy of the proposed approach is illustrated using a long-span truss with finite-element formulation and an 8-story nonlinear base-isolated building. Simulation results demonstrate that the proposed approach is capable of tracking the local structural damages without the global information of the entire structure, and it is suitable for local structural health monitoring.

• 한국구조물진단유지관리공학회 논문집
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• 제23권3호
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• pp.65-74
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• 2019

본 연구에서는 노후화된 공동주택 수직 증축 리모델링 시 면진시스템의 적용성을 검토 및 면진시스템 적용을 위한 기초자료를 제공할 목적으로 동일한 구조로 수직 증축 시 수직 층수와 면진주기에 따른 최적 면진주기를 산정하였다. 해석결과, 3개층 수직 증축 시에는 면진주기를 비면진 건물 주기의 2배 이상, 2개층 수직 증축 시에는 비면진 건물 주기의 3배 이상을 확보하여야만 충분한 면진효과를 나타내는 것을 알 수 있었다. 또한, 1개층 수직 증축 시에는 비면진 건물 주기의 4배 이상을 확보하여야만 면진효과를 나타내었다. 위의 결과를 활용하여 3개층 수직증축 리모델링 대상 공동주택에 면진시스템을 적용하여 그 효과를 검증하였다. 최상층 최대응답가속도가 비면진 건물의 최대응답가속도 보다 X방향의 경우에는 약 70%로, Y방향의 경우에는 약 65%의 감소를 나타내었다. 또한, 밑면 전단력의 경우, 비면진 건물과 비교하여 X방향 및 Y방향 모두 약 30% 감소하는 것으로 나타났다.

• 한국재난정보학회 논문집
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• 제14권4호
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• pp.450-457
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• 2018

연구목적: 2016년 9월 경주 이후 구조물 및 비구조물의 지진 안전성 및 내진성능에 관한 문제가 이슈화 되고 있으며, 특히 배관 시스템의 경우 구조요소 보다 지진 발생시 내진성능에 있어서 취약하다고 볼 수 있다. 스프링클러 배관 시스템과 같은 비구조적 구성요소의 손상으로 인해 지진 발생 및 이후에 상당한 경제적 손실이나 생명 손실을 초래 할 수 있다. 연구방법: 본 연구는 Triple Friction Pendulum Bearings (TPBs)을 설치한 건물 배관 시스템을 이용한 소방 배관 시스템의 내진성능평가를 제시한다. Kobe, Kocaeli, GyeongJu 지진을 고려하여 지반 운동의 불확실성을 고려하였다. 연구결과: 빌딩 시스템과 파이핑 시스템의 첫 번째 모드는 각각 약 5.8Hz와 약 2.742Hz로 나타났으며, 또한 TPBs 시스템이 적용된 배관 시스템의 최대 변위는 Kobe, Kocaeli 및 GyeongJu 지진의 경우 각각 49%, 14.4%, 21.5%가 감소한 것으로 나타났다. 결론: 따라서 건물 배관 시스템에서 지진 격리 시스템을 사용하면 지진이 심할 때 TPB가 없는 일반적으로 설치된 걸물 배관 시스템보다 지진 위험을 줄일 수 있다.