• 한국강구조학회 논문집
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• 제27권1호
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• pp.119-129
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• 2015

강재량을 줄이면서도 풍하중의 영향을 완화시킬 수 있는 장점으로, 수평재로 서로 연결된 다수의 수직 원형강관으로 구성된 멀티기둥 풍력타워 시스템은 기존의 단일 실린더형 타워구조에 대한 대안으로 고려될 수 있다. 멀티기둥 타워를 하나의 타워구조로 거동하게 하기 위해서는 수직 강관과 수평 강관의 연결부인 강관조인트의 강도 확보가 중요하다. 본 연구에서는 멀티기둥에 적용될 수 있는 T 조인트의 강도평가를 수행하였다. AISC, Eurocode3, ISO 19902, CIDECT의 4가지 강관조인트 설계기준을 검토하고, 조인트에서 주강관과 지강관의 세장비에 대한 매개변수해석을 통하여 설계기준에서 제공되는 강도산정식의 타당성을 검토하였다.

• Wind and Structures
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• 제1권3호
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• pp.225-241
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• 1998

The high-rise supporting towers of long-span suspension and cable-stayed bridges commonly comprise a pair of slender prisms of roughly square cross-section with a center-to-centre spacing of from perhaps 2 to 6 widths and connected by one or more cross-ties. The tower columns may have a constant spacing as common for suspension bridges or the spacing may reduce towards the top of the tower. The present paper is concerned with the aerodynamics of such towers and describes an experimental investigation of the overall aerodynamic forces acting on a pair of square cylinders in two-dimensional flow. Wind tunnel pressure measurements were carried out in smooth flow and with a longitudinal intensity of turbulence 0.10. Different angles of attack were considered between $0^{\circ}$ and $90^{\circ}$, and separations between the two columns from twice to 13 times the side width of the column. The mean values of the overall forces proved to be related to the bias introduced in the flow by the interaction between the two cylinders; the overall rms forces are related to the level of coherence between the shedding-induced forces on the two cylinders and to their phase. Plots showing the variation of the force coefficients and Strouhal number as a function of the separation, together with the force coefficients spectra and lift cross-correlation functions are presented in the paper.

• 국제초고층학회논문집
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• 제1권4호
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• pp.271-281
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• 2012

Tianjin Goldin Finance 117 tower has an architectural height of 597 m, total of 117 stories, and the coronation of having the highest structural roof of all the buildings under construction in China. Structural height-width ratio is approximately 9.5, exceeding the existing regulation code significantly. In order to satisfy earthquake and wind-resisting requirements, a structure consisting of a perimeter frame composed of mega composite columns, mega braces and transfer trusses and reinforced concrete core containing composite steel plate wall is adopted. Complemented by some of the new requirements from the latest Chinese building seismic design codes, design of the super high-rise building in high-intensity seismic area exhibits a number of new features and solutions to professional requirements in response spectrum selection, overall stiffness control, material and component type selection, seismic performance based design, mega-column design, anti-collapse and stability analysis as well as elastic-plastic time-history analysis. Furthermore, under the prerequisite of economic viability and a series of technical requirements prescribed by the expert review panel for high-rise buildings exceeding code limits, the design manages to overcome various structural challenges and realizes the intentions of the architect and the client.

• KSBB Journal
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• 제17권2호
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• pp.142-147
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• 2002

기포탑 회분식 xanthan 발효에서 xanthan 생성속도와 분자량에 영향을 미치는 산소전달제한을 피하기 위하여 과산화수소수를 산소공금 보조수단으로 사용하였다. 과산화수소수 주 입은 xanthin 생성을 가역적으로 저해하였다. 반면이 직경 8 mm 유리구슬 유동화 입자는 기-액 산소전달속도를 증가시켜서 기-액-고 삼상유동충 생물반응기에서의 xanthan 발효는 기포탑 발효에 비하여 높은 단위균체량 당 xanthan 생성속도 및 점도수윤 그리고 반응기 공간-시간 수윤(space-time yield)을 보였다.

• 국제초고층학회논문집
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• 제1권1호
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• pp.37-51
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• 2012

New generation of tall and complex buildings systems are now introduced that are reflective of the latest development in materials, design, sustainability, construction, and IT technologies. While the complexity in design is being overcome by the availability and advances in structural analysis tools and readily advanced software, the design of these buildings are still reliant on minimum code requirements that yet to be validated in full scale. The involvement of the author in the design and construction planning of Burj Khalifa since its inception until its completion prompted the author to conceptually develop an extensive survey and real-time structural health monitoring program to validate all the fundamental assumptions mad for the design and construction planning of the tower. The Burj Khalifa Project is the tallest structure ever built by man; the tower is 828 meters tall and comprises of 162 floors above grade and 3 basement levels. Early integration of aerodynamic shaping and wind engineering played a major role in the architectural massing and design of this multi-use tower, where mitigating and taming the dynamic wind effects was one of the most important design criteria established at the onset of the project design. Understanding the structural and foundation system behaviors of the tower are the key fundamental drivers for the development and execution of a state-of-the-art survey and structural health monitoring (SHM) programs. Therefore, the focus of this paper is to discuss the execution of the survey and real-time structural health monitoring programs to confirm the structural behavioral response of the tower during construction stage and during its service life; the monitoring programs included 1) monitoring the tower's foundation system, 2) monitoring the foundation settlement, 3) measuring the strains of the tower vertical elements, 4) measuring the wall and column vertical shortening due to elastic, shrinkage and creep effects, 5) measuring the lateral displacement of the tower under its own gravity loads (including asymmetrical effects) resulting from immediate elastic and long term creep effects, 6) measuring the building lateral movements and dynamic characteristic in real time during construction, 7) measuring the building displacements, accelerations, dynamic characteristics, and structural behavior in real time under building permanent conditions, 8) and monitoring the Pinnacle dynamic behavior and fatigue characteristics. This extensive SHM program has resulted in extensive insight into the structural response of the tower, allowed control the construction process, allowed for the evaluation of the structural response in effective and immediate manner and it allowed for immediate correlation between the measured and the predicted behavior. The survey and SHM programs developed for Burj Khalifa will with no doubt pioneer the use of new survey techniques and the execution of new SHM program concepts as part of the fundamental design of building structures. Moreover, this survey and SHM programs will be benchmarked as a model for the development of future generation of SHM programs for all critical and essential facilities, however, but with much improved devices and technologies, which are now being considered by the author for another tall and complex building development, that is presently under construction.

• 한국미생물·생명공학회지
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• 제20권5호
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• pp.607-613
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• 1992

침강조의 중앙에 깔대기 모양의 판을 설치하고 방해판 아래 다시 공기 방울과 CO2 가스의 별도 배출구를 설치하여 상부로의 난류를 방지하므로 침강 효율이 그게 향상되도록 settler를 고안하였다. 이 settler를 설치한 탑형 발효조에서 응집성효모 S.uvarum의 에탄올 생산성을 검토한 결과 방해판을 설치하지 않은 단순한 원통형 settler에 비하여 1.5배 증대되었다. 또한 탑형 발효조에서 살펴본 균체 순환율이 에탄올 생산성에 미치는 영향을 살펴본 결과 균체 순환울 1-5 사이에서는 에탄올 생산성의 변화가 거의 없었으나 6 이상에서는 균체가 유출되므로 에탄올 생산성이 감소하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 가을 학술발표회 논문집
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• pp.475-480
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• 1997

Highrise concrete buildings are very sensitive to cumulative and differential shortening of their vertical element such as wall and columns. Inelastic deformation due to creep and shrinkage consist of various factors and load history af actual building is very complicated. Therefore, for the accurate prediction and compensation of axial shortening, special efforts in design and construction phase are required to ensure long-term serviceability and strength requirement. In this paper, axial shortening estimation and compensation procedure is presented, which utilized experimentally determined concrete properties and preliminary load history and computerized approach, in case of Plaza Rakyat office tower, 79-story reinforced concrete building under construction in Malaysia.

• Structural Engineering and Mechanics
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• 제23권6호
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• pp.635-649
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• 2006

The static and dynamic responses of guyed telecommunication towers can be determined by using two models, the space truss element model, and the equivalent beam-column element model. The equivalent beam-column analysis is based on the determination of the equivalent shear, torsion, and bending rigidities as well as the equivalent area of the guyed mast. In the literature, two methods are currently available to determine the equivalent properties of lattice structures, namely: the unit load method, and the energy approach. In this study, an equivalent beam-column analysis is introduced based on an equivalent thin plate approach for lattice structures. A finite-element modeling, using suitably modified ABAQUS software, is used to investigate the accuracy of utilizing the different proposed methods in determining the static and dynamic responses of a guyed tower of 364.5-meter high subjected to static and seismic loading conditions. The results from these analyses are compared to those obtained from a finite-element modeling of the actual structure using 3-D truss and beam elements. Good agreement is shown between the different proposed beam-column models, and the model of the actual structure. However, the proposed equivalent thin plate approach is simpler to apply than the other two approaches.

• 한국강구조학회 논문집
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• 제29권5호
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• pp.377-387
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• 2017

이 연구에서는 강판 매입형 합성기둥의 Push-out Test를 통해 강재와 콘크리트의 부착면적에 따른 영향을 알아보았다. 이로써 부착면적이 넓을수록 부착응력은 작아진다는 경향이 조사되었다. 또한 소규모 매입형 합성기둥의 경우에는 설계기준에서 제시하는 공칭부착 응력값이 과소하게 적용되는 것을 확인하였다. 다음으로 H형강 매입형 합성기둥의 Push-out Test를 통해 전단연결재의 수와 간격에 따른 영향을 알아보았다. 이로써 전단연결재의 전단거동을 파악할 수 있었다.

• 한국토양환경학회지
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• 제2권1호
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• pp.83-90
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• 1997

저농도의 난 수용성 VOC가스가 포함되어 있는 다량의 오염가스를 처리하기 위하여 흡수탑과 생물반응기의 결합체인 새로운 처리시스템을 제시하였다. 바이오스크러버의 스크러버에서는 세정액으로 기상중의 처리대상오염물질의 흡수가 일어나며 세정액은 생물반응기로 이송되어 호기성 미생물이 오염물을 분해시킨다. 본 연구에서는 폐가스중의 VOC분리를 위하여 재순환가능한 고비점용매를 사용하였다. 고비점용매를 포함한 세정액은 기/액 향류접촉이 이루어지는 흡수탑의 충전층에서 폐가스중의 오염물을 분리한다. 흡수탑은 Pall ring충전제로 채워 실제공정을 모사 하고자 하였다. 흡수처리후 생물반응기로 이송된 흡수액은 재생 후 다시 흡수탑으로 재 순환하였다. 실험에 사용된 대상가스는 농도가 400 mg/$\textrm{m}^3$ 인 톨루엔으로, 세정액이 가스흐름과 향류로 약 10~15L/min의 유량으로 충전층을 적시며 내려오는 충전탑내부로 약 100 L/min의 유량으로 도입하였다. VOC처리를 위해 제작된 본 바이오스크러버에서 고비점용매를 이용한 연속실험결과 최적운전 조건에서 약 80%의 처리율을 얻을 수 있었다.