• Journal of Korean Association for Spatial Structures
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• v.18 no.4
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• pp.41-48
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• 2018

Recently, the concept of an outrigger damper system with a damper added to the existing outrigger system has been developed and applied for dynamic response control of high-rise buildings. However, the study on the structural characteristics and design method of Outrigger damper system is in the early stages. In this study, a 50 story high - rise building was designed and an outrigger damper system with viscoelastic damper was applied for wind response control. The time history analysis was performed by using the kaimal spectrum to create an artificial wind load for a total of 1,000 seconds at 0.1 second intervals. Analysis of the top horizontal maximum displacement response and acceleration response shows that outrigger damper systems are up to 28.33% and 49.26% more effective than conventional outrigger systems, respectively. Also, it is confirmed that the increase of damping ratio of dampers is effective for dynamic response control. However, since increasing the damping capacity increases the economic burden, it is necessary to select the appropriate stiffness and damping value of the outrigger damper system.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.1
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• pp.69-77
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• 2013

When structural design of a tall building is conducted, reduction of wind-induced lateral displacement is one of the most important problem. For this purpose, additional dampers and vibration control devices are generally considered. In this process, control performance of additional devices are usually investigated for optimal design without variation of characteristics of a structure. In this study, multi-objective integrated optimization of structure-smart control device is conducted and possibility of reduction of structural resources of a tall building with additional smart damping device has been investigated. To this end, a 60-story diagrid building structure is used as an example structure and artificial wind loads are used for evaluation of wind-induced responses. An MR damper is added to the conventional TMD to develop a smart TMD. Because dynamic responses and the amount of structural material and additional smart damping devices are required to be reduced, a multi-objective genetic algorithm is employed in this study. After numerical simulation, various optimal designs that can satisfy control performance requirement can be obtained by appropriately reducing the amount of structural material and additional smart damping device.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.29 no.3
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• pp.261-268
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• 2016

Tuned Liquid Dampers(TLD) are energy dissipation devices that have been proposed to control the dynamics response of structure. The TLD has been shown to effectively control the wind response of structures. However, controlling responses of structures with TLD under seismic loads are not fully investigated. The objective of this study is to evaluate the seismic performance of single degree of freedom(SDF) with TLDs having various tuning and mass raitos. For this purpose, analytical studies are conducted. Different soil conditions are considered in this study. As a result, performance of TLD, appeared diffrently depending on the natural period, damping ratio of the structure. Also TLD tuning ratio appeared differently.

• Computational Structural Engineering
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• v.11 no.1
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• pp.27-37
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• 1998

본 고에서는 지진해석과 관련하여 가장 중요한 원칙과 해석법에 대한 개략을 제시하여 철근콘크리트 구조물의 지진해석과 관련된 용어 및 특수과제를 언급하고자 한다. 이 해석의 위력이나 매력적인 점에도 불구하고 지진응답에 대한 해석은 항상 많은 불확실성에 부닥칠 수 있다는 것을 강조하고자 한다. 해석은 설계과정의 한 단계에 불과하여 수많은 컴퓨터 출력 페이지가 빈틈없는(sound) 기술적 판단을 대신하여서는 안된다. 구조물에 있어서의 지진력은 외부에서 가해진 하중으로부터 발생하는 것이 아니다. 구조물에 압력 및 흡입력으로 작용하는 풍하중과는 달리, 구조물의 기저(base)에서의 주기적 운동에 의한 응답으로서 상부구조물은 가속도를 받게 되고 따라서 관성력으로서 지진력이 얻어지게 된다. 지진응답은 기본적으로 동적인 성질을 가지며 고유주기와 감쇠와 같은 동적 특성은 이 응답을 결정하는데 결정적인 역할을 한다. 만약 지진해석이 실제적인 것이 되자면, 단순화된 방식으로라도 이러한 동적 특성을 고려할 수 있는 것이어야 한다. 이러한 동적 성질이 복잡성의 한 요인이며, 다른 요인으로서 해석적 장애가 존재한다. 대부분의 구조물은 최대지진에 대하여 상당한 항복현상을 나타냄으로써 저항하도록 설계하고 있다. 따라서 설계자는 최대지진에 대한 구조물의 비선형 동적 거동에 대하여 어느 정도 이해를 하고 있어야 한다. 원칙적으로 이것은 매우 복잡하고 어려운 해석적 문제를 제기하게 된다. 실제로는 매우 단순화된 해석법, 적절한 설계 및 상세의 조합만으로도 만족스러운 거동을 얻는 것에 부족함이 없다. 어쨌든 이러한 해석기법의 바탕과 한계를 이해하는 것은 필수적이다.tidyl ethanolamine$(20.9{\sim}29.7%)$, phosphatidyl inositol$(18.4{\sim}26.1%)$ 순으로 많았다. 각 구성지질의 지방산조성은 4종의 버섯 공히 linoleic acid와 palmitic acid가 주요 지방산이었으나 싸리버섯은 중성지질에서 oleic acid의 함량이 높았다.n the part of special landscape management area, it is necessary to introduce landscape impact assessment system to more effective landscape management.ch served as supporting organizations. The control of the construction and management of the royal garden and landscape was held by decision makers, executors of works and management. 2) The general process of the construction and management of the royal garden and landscape included Sangji and Kyuho다 as the first step; In case of buildings and facilities, according to former examples and drawings, the most of the planning and design was already fixed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.11
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• pp.5306-5313
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• 2011

Most previous studies for finding optimal design parameters of a tuned mass damper(TMD) have been focused on the harmonic excited single-degree-of freedom system. In this study, optimal values of damping ratio and tuning frequency ratio of a TMD applied to control a seismically excited structure are investigated through numerical analyses. Considering that the structural responses due to earthquake loads are strongly dependent on the soil condition, the site effects on the optimal parameters of the TMD are studied and compared to those presented by previous studies. Numerical analyses results indicate that better control performance can be obtained by using the parameters proposed by this study in the seismic application of the TMD.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.4
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• pp.323-330
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• 2012

This study deals with the experiments of liquid dampers with multi cells whose vertical tubes are divided into several square columns for easily changing natural frequencies. Shaking table test is performed to verify control effectiveness of the dampers which are installed on a building structure. To design liquid dampers, a 64-story building structure is reduced to a SDOF structure with 1/20 of similitude laws based on acceleration. The structure model is made up to adjust its mass and stiffness easily, with separate mass and drive parts. Mass parts indicate real structure's weights and drive parts indicate real structure's stiffness with springs and LM guides. Manufactured liquid damper has 18 cells and its natural frequency ranges are 0.65Hz to 0.81Hz. Shaking table test is carried out with one way excitation to compare with only accelerations of a large-scale structure and a structure installed with liquid dampers. Control performance of the liquid damper is expressed by the transfer function from shaking table accelerations to the large-scale structure ones. Testing results show that the liquid damper reduced a large-scale structure's response by tuned natural frequencies.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.2
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• pp.200-206
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• 2013

The paper was investigated on the mooring forces(or tension) and motion response characteristics for a 8-point mooring floating dock in regular waves using a commercial code(AQWA). To achieve the aim of the research, a numerical simulation was adapted on an inner port environment condition, which the water depth is 10 meters, significant wave amplitude(1.05 m). wave period(3.85 sec), wind speed(20.21 m/s), wind and current direction ($90^{\circ}$), incident waves(${\chi}=180^{\circ}$, $135^{\circ}$ and $90^{\circ}$). The dimension of the numerical model is length(140 m), breadth(32 m), depth(14.6 m). The maximum length of a mooring line is 120m. We can expected that roll and pitch motions appeared in beam seas better than head sea. the mooring forces also indicated higher in bean seas than in head seas including wind forces.

• KSBB Journal
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• v.8 no.4
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• pp.328-335
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• 1993

A flow injection analysis(FIA) system was developed for the determination of cholesterol using immobilized cholesterol oxidase and cholesterol ester hydrolase. The enzymes were immobilized on controlled pore galas(CPG) by the glutaraldehyde method. The glass colunms packed with immobilized enzymes were found to contain 3-5 I.U. for each enzyme. A hydrogen peroxide sensitive electrode was contructed and applied to the FIA system. The operational conditions for FIA response were investigated and optimized with variation of sampling volume, flow rate and composition of carrier solution. The FIA response were linear upto 60 and 400mg/m1 for free cholesterol and cholesterol ester, respectively. All samples were analyzed with a good precision (<2.5% CV) and accuracy. 23 samples were mea sured succesively within about an hour. Intermittent assays of more than 500 times caused 50% decrease in response sensitivity.

• Journal of Korean Society of Steel Construction
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• v.18 no.2
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• pp.173-180
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• 2006

The seismic responses of a building are affected by the base soil conditions. In this study, linear time-history seismic analysis and nonlinear pushover static seismic analysis were performed to estimate the base shear forces of 3-, 5-, and 7-story steel buildings, considering the rigid and soft soil conditions. Foundation soil stiffness, based on the equivalent static stiffness formula, is used for the damper, one of the Link elements in SAP 2000. The base shear forces of the steel buildings, estimated through time-history analysis using the general-purpose structural-analysis program of SAP 2000, were compared with those calculated using the domestic seismic design code, the UBC-97 design response spectrum. and pushover static nonlinear analysis. The steel buildings designed for gravity and wind loads showed elastic responses with a moderate earthquake of 0.11 g, while the elastic soft-soil layer increased the displacement and the base shear force of the buildings due to soil-structure interaction and soil amplification. Therefore, considering the characteristics of the soft-soil layer, it is more reasonable to perform an elastic seismic analysis of a building's structure during weak or moderate earthquakes.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.439-442
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• 2002

In this study, a turbulence simulation is carried out in a suction type wind tunnel using grids, where turbulent flows with various turbulence intensity are successfully produced by the change of grid size, arrangement of grids and settling position, respectively. Response tests of rectangular cylinder models with aspect ratio of 2 and 4 are carried out in smooth flow and generated turbulent flows. Additionally, two types of fairing are considered such as right triangle and regular triangle. The effects of wind velocity fluctuations and fairing are discussed on vortex-induced oscillation.