• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 봄 학술발표회 논문집
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• pp.55-60
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• 2002

The columns and The belt wall of Tower Palace III were desined as 800kg/c $m^2$ ultra-high strength concrete. The concrete should meet or exceed the requirements of slump of 23cm, $\sigma$$_{18H}$ of 100kg/c $m^2$, $\sigma$$_{91th}$ of, 800kg/c $m^2$. The concrete mixings with 4 different domestic Silica fumes were investigated. Laboratory tests, the pilot productions of batcher plant and the full-scale mock up tests were performed. As results of site application, all test results are satisfied with the requirements of columns and belt wall.l.

• Structural Engineering and Mechanics
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• 제71권4호
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• pp.417-432
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• 2019

Seismic performance analysis of steel-brace reinforced concrete (RC) frame using topology optimization in highly seismic region was discussed in this research. Topology optimization based on truss-like material model was used, which was to minimum volume in full-stress method. Optimized bracing systems of low-rise, mid-rise and high-rise RC frames were established, and optimized bracing systems of substructure were also gained under different constraint conditions. Thereafter, different structure models based on optimized bracing systems were proposed and applied. Last, structural strength, structural stiffness, structural ductility, collapse resistant capacity, collapse probability and demolition probability were studied. Moreover, the brace buckling was discussed. The results show that bracing system of RC frame could be derived using topology optimization, and bracing system based on truss-like model could help to resolve numerical instabilities. Bracing system of topology optimization was more effective to enhance structural stiffness and strength, especially in mid-rise and high-rise frames. Moreover, bracing system of topology optimization contributes to increase collapse resistant capacity, as well as reduces collapse probability and accumulated demolition probability. However, brace buckling might weaken beneficial effects.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.445-448
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• 2006

Mix design of C80A which is applied to the vertical members of The Burj Dubai Tower, the tallest building of the world, was performed so as to meet the requirements of rheological property, mechanical properties & construction sequences based on material analysis in Dubai, UAE. Experimental investigations were carried out to evaluate & optimize the quantities of total binders, the proportions of Micro Silica, Dune Sand & PFA, changes of S/a and the comparison of chemical admixture, etc. Approximately $65,000m^3$ of C80A concrete has been poured to the vertical members since 16-Apr-2006. In the actual application, it was showed that C80A has proper early strength achievement, excellent mechanical properties and satisfactory flowability & workability. The results of extensive site testing can be summarized that the average compressive strength at 28days is 98.8MPa, the average elastic modulus at 28days is 47.8GPa, the flow of concrete after pumping at the height of 250m (L72) was over 500mm.

• 한국건축시공학회지
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• 제12권2호
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• pp.203-210
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• 2012

최근 국내에서는 대형 및 초고층화 건축물에 대한 관심과 수요가 증가하고 있는 추세와 함께 콘크리트의 성능이 중요시 되고 있다. 이를 뒷받침하는 기술로 매스콘크리트 및 고강도 콘크리트 시공기술의 확보는 대단히 중요하다. 고강도 콘크리트의 경우 다량의 분체량에 따른 시멘트의 수화반응(hydration) 활성으로 콘크리트 내부에 높은 온도의 수화열이 발생하고 외부와 온도차로 인한 열응력의 증가 및 그로인한 균열, 슬럼프 로스현상 등의 문제점들이 많이 발생하고 있어 대책이 필요한 실정이다. 본 연구에서는 매스콘크리트 및 고강도 콘크리트의 수화열을 제어하기 위하여 혼화재의 종류와 혼입량의 변화, 배합수를 Ice-flake로 100% 대체함으로써 고강도 콘크리트의 수화열을 저감하고자 하였으며, 실험결과 콘크리트의 수화열 저감 방안으로 혼화재는 고로슬래그와 플라이 애쉬를 사용하고 배합수로 Ice-flake를 사용함으로써 콘크리트의 유동성개선 및 슬럼프로스 저감효과를 볼 수 있으며, 콘크리트 최고 온도를 크게 떨어트려 매스 콘크리트 및 고강도 콘크리트의 수화열에 의한 균열저감 및 품질향상에 크게 기여할 것으로 판단된다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.533-536
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• 1999

The primary purpose of this study is to investigate experimentally the effect of steel fiber reinforcement on the total energy dissipation capacity of R/C flexural members and to make a contribution to the construction of 40~60 story R/C high rise building by developing the new materials and reinforcing details which can improve the seismic performance of high-strength R/C beam-column joints. Experimental research was carried out on 4 type specimen under cyclic loading. Main variables are steel fiber reinforcement, intermediate reinforcements and yield strength of rebars. From the test results, steel fiber reinforcement can improve the ductility of R/C flexural members.

• 한국건축시공학회지
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• 제7권4호
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• pp.153-159
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• 2007

Recently, as a result of the economic growth, the concentration of population towards the cities and the rise in land prices, the demand for high rise buildings has increased significantly, the trend to build high rise buildings such as the mixed-use development buildings by the domestic construction companies continues. It's very important what kind of form work system is applied on the Core Wall of the high rise buildings to determine the economic efficiency for the whole project. That's because the appropriate selection of the Formwork system enables the construction cost lower, makes the good quality of the finished concrete, reduces the construction period, assurance of safety, and further more, it enables to achieve the successful performance of the projects. Therefore, this research, after comparing the strength and the weakness between the construction methods, focus the point to provide a builder the basic data to choose the right Formwork method.

• Earthquakes and Structures
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• 제5권4호
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• pp.439-459
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• 2013

Main objective of the present study is to determine the statistical properties and suitable probability distribution functions of spectral displacements from nonlinear static and nonlinear dynamic analysis within the frame work of Monte Carlo simulation for typical low rise and high rise RC framed buildings located in zone III and zone V and designed as per Indian seismic codes. Probabilistic analysis of spectral displacement is useful for strength assessment and loss estimation. To the author's knowledge, no study is reported in literature on comparison of spectral displacement including the uncertainties in capacity and demand in Indian context. In the present study, uncertainties in capacity of the building is modeled by choosing cross sectional dimensions of beams and columns, density and compressive strength of concrete, yield strength and elastic modulus of steel and, live load as random variables. Uncertainty in demand is modeled by choosing peak ground acceleration (PGA) as a random variable. Nonlinear static analysis (NSA) and nonlinear dynamic analysis (NDA) are carried out for typical low rise and high rise reinforced concrete framed buildings using IDARC 2D computer program with the random sample input parameters. Statistical properties are obtained for spectral displacements corresponding to performance point from NSA and maximum absolute roof displacement from NDA and suitable probability distribution functions viz., normal, Weibull, lognormal are examined for goodness-of-fit. From the hypothesis test for goodness-of-fit, lognormal function is found to be suitable to represent the statistical variation of spectral displacement obtained from NSA and NDA.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2003년도 학술대회지
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• pp.202-213
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• 2003

타워팰리스 III 현장은 현존하는 국내 건축물로는 가장 높은 초고층 주상복합건물이다. 초고층 현장에는 일반현장과는 다른 시공기술 및 엔지니어링 기술의 적용이 요구되는 바, 타워팰리스 III 현장은 지금까지 축적된 기술을 바탕으로 보다 발전된 시공기술과 엔지니어링 기술, 그리고 공정관리기법을 통하여 마감공사 포함 충 당 13.4일이라는 공사 속도를 달성하였다. 이와 같은 공사를 성공적으로 수행하기 위하여 적용된 첨단 시공기술로 1) 골조공사 및 외벽공사의 3-Day Cycle을 달성하기 위한 여러 가지 공법, 2) 초고층 주거건물의 마감공사 공정관리를 위한 Tact 공정관리 시스템, 3) 현장관리 시스템으로 물류관리 및 정보공유 시스템 등이 적용되었다. 또한 엔지니어링 요소기술로 1) 고유동 무다짐 콘크리트와 국내 최초의 압축강도 $800kgf/cm^{2}$의 초고강도 콘크리트 등의 New Material, 2) 냉각수 순환형 파이프쿨링 시스템 등의 New Method, 3) Smart Fan Control 주방환기 시스템을 포함한 Mechanical System 4) False Car System을 포함한 Electrical System 등이 있다.

• 국제초고층학회논문집
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• 제3권2호
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• pp.107-120
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• 2014

A Reinforced concrete (RC) shear wall system with coupling beams has been known as one of the most promising structural systems for high-rise buildings. However, significantly large flexural and/or shear stress demands induced in the coupling beams require special reinforcement details to avoid their undesirable brittle failure. In order to solve this problem, one of promising candidates is frictional hysteretic energy dissipating devices (HEDDs) as an alternative to the coupling beams. The introduction of frictional HEDDs into a RC shear wall system increases energy dissipation capacity and maintains the frame action after their yielding. This paper investigates the strength demands (specifically yield strength levels) with a maximum allowable ductility of frictional HEDDs based on comparative non-linear time-history analyses of a prototype RC shear wall system with traditional RC coupling beams and frictional HEDDs. Analysis results show that the RC shear wall systems coupled by frictional HEDDs with more than 50% yield strength of the RC coupling beams present better seismic performance compared to the RC shear wall systems with traditional RC coupling beams. This is due to the increased seismic energy dissipation capacity of the frictional HEDD. Also, it is found from the analysis results that the maximum allowable ductility demand of a frictional HEDD should increase as its yield strength decreases.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문 발표회
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• pp.33-36
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• 2003

Time-dependent axial shortening in the cores and columns of tall concrete buildings requires special attention to ensure proper behavior for strength of the structure and the nonstructural clement. The effects of column shortening, both elastic and inelastic, take on added significance and need special consideration in design and construction with increased height of structures. In this paper, the compensation method of column shortening are introduced. It could be conclued that the survey is a significant factor for the compensation of column shortening.