• Title/Summary/Keyword: concrete high-rise structures

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Compressive Strength Properties Surface Coating Lightweight Aggregate ITZ using Inorganic Materials (무기 재료를 이용한 표면코팅 경량골재 계면 압축강도 특성)

  • Kim, Ho-Jin;Jeong, Su-Mi;Pyeon, Myeong-Jang;Kim, Ju-Sung;Park, Sun-Gyu
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2022.04a
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    • pp.109-110
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    • 2022
  • Recently, it tend to increase the high-rise and large-scale of buildings and the developtment of construction technology can to be applied reinforced concrete structures to high-rise buildings. However, when a high-rise buildings is constructed with reinforced concrete, it has a disadvantage that buildings weight increases. In order to resolve the weight of reinforced concrete structures, various types of lightweight aggregates become development and research. Although lightweight aggregates can be reduced the weight of concrete, the strength of ITZ(Interfacial Transition Zone) is lowered due to its less strength than natural aggregates. In this study, an experimental study was conducted to coat the surface of lightweight aggregates with GGBFS(ground granulated blast furnace slag) to improve the strength of cement matrix mixed with lightweight aggregates. Result of this experimental study shows that the compressive strnegth of the surface coating lightweight aggregates was higher than general lightweight aggregates. Also, it was considered that this is because the pore at the ITZ of the surface-coated lightweight aggregates mixed cement matrix are filled with GGBFS fine particle.

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AMG-CG method for numerical analysis of high-rise structures on heterogeneous platforms with GPUs

  • Li, Zuohua;Shan, Qingfei;Ning, Jiafei;Li, Yu;Guo, Kaisheng;Teng, Jun
    • Computers and Concrete
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    • v.29 no.2
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    • pp.93-105
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    • 2022
  • The degrees of freedom (DOFs) of high-rise structures increase rapidly due to the need for refined analysis, which poses a challenge toward a computationally efficient method for numerical analysis of high-rise structures using the finite element method (FEM). This paper presented an efficient iterative method, an algebraic multigrid (AMG) with a Jacobi overrelaxation smoother preconditioned conjugate gradient method (AMG-CG) used for solving large-scale structural system equations running on heterogeneous platforms with parallel accelerator graphics processing units (GPUs) enabled. Furthermore, an AMG-CG FEM application framework was established for the numerical analysis of high-rise structures. In the proposed method, the coarsening method, the optimal relaxation coefficient of the JOR smoother, the smoothing times, and the solution method for the coarsest grid of an AMG preconditioner were investigated via several numerical benchmarks of high-rise structures. The accuracy and the efficiency of the proposed FEM application framework were compared using the mature software Abaqus, and there were speedups of up to 18.4x when using an NVIDIA K40C GPU hosted in a workstation. The results demonstrated that the proposed method could improve the computational efficiency of solving structural system equations, and the AMG-CG FEM application framework was inherently suitable for numerical analysis of high-rise structures.

The self-compacting property of concrete as to specific gravity and mixing proportion of lightweight coarse aggregate (경량 굵은골재 비중 및 혼합률에 따른 콘크리트의 자기충전성)

  • Choi, Yun-Wang;Kim, Yong-Jic;Choi, Wook;Lee, Sang-Ho;Cho, Sun-Kyu
    • Proceedings of the Korea Concrete Institute Conference
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    • 2004.11a
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    • pp.747-750
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    • 2004
  • Lightweight concrete is known for its advantage of reducing the self-weight of the structures, reducing the areas of sectional members as well as making the construction convenient. Thus the construction cost can be saved when applied. to . structures such as long-span bridge and high rise buildings. However, the lightweight concrete requires specific design mix method that is quite different from the typical concrete, since using the typical mix method would give rise the material segregation as well as lower the strength by the reduced weight of the aggregate. In order to avoid such problems, it is recommended to apply the design mix method of high performance self-compacting concrete for the lightweight concrete. Therefore, this study introduces a production of self-compacting concrete, PF-modified and improved version of Nan-Su's design mix method of self-compacting concrete. Through a series of test mixes conducted during the study, the quality of the concrete at its fresh condition has been evaluated per the 2nd class rating standards of self-compacting concrete published by JSCE, especially focused in its fluidity, segregation resistance ability, and filling ability.

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A Study on Fire Resistance Performance Evaluation for Field Application of Ultra-High Strength Concrete (초고강도 내화 콘크리트의 현장 적용을 위한 내화성능 평가에 관한 연구)

  • Baek, Young-Woon;Yuk, Tae-Won;Park, Dong-Soo;Kim, Han-Sol;Lee, Hang-Seung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2023.11a
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    • pp.41-42
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    • 2023
  • The physical performance of high-strength concrete deteriorates when exposed to high temperatures such as fire. In particular, in the case of ultra-high-strength concrete, there is a high possibility of explosion due to internal water pressure and thermal expansion due to the tight internal structure. In this paper, a fire resistance certification test was conducted for field application of ultra-high-strength fire-resistant concrete, and the fire resistance performance (temperature rise of main rebar) was compared according to the structural concrete cover thickness. As a result, when the covering thickness was 40 mm, three structures did not meet the certification standards, and when the covering thickness was 50 mm, all structures met the fire resistance certification standards.

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Temperature Crack Contol in Subway Box Structures (지하철 박스 구조물에서의 온도균열제어)

  • Koo, Bon-Chang;Kim, Dong-Seuk;Ha, Jae-Dam;Kim, Ki-Soo;Choi, Long;Oh, Byung-Hwan
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.04a
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    • pp.293-298
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    • 1999
  • The crack of concrete induced by the heat of hydration is a serious problem, particularly in concrete structures such as underground box structure, mat-slab of nuclear reactor buildings, dams or large footings, foundations of high rise buildings, etc.. As a result of the temperature rise and restriction condition of foundation, the thermal stress which may induce the cracks can occur. Therefore the various techniques of the thermal stress control in massive concrete have been widely used. One of them is prediction of the thermal stress, besides low-heat cement which mitigates the temperature rise, pre-cooling which lowers the initial temperature of fresh concrete with ice flake, pipe cooling which cools the temperature of concrete with flowing water, design change which considers steel bar reinforcement, operation control and so on. The objective of this paper is largely two folded. Firstly we introduce the cracks control technique by employing low-heat cement mix and thermal stress analysis. Secondly it show the application condition of the cracks control technique like the subway structure in Seoul.

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The Residential Satisfaction of Residents in High-rise Mixed-use Apartments (초고층 주상복합아파트 거주자의 주거만족도)

  • 강순주;이수현
    • Journal of the Korean Home Economics Association
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    • v.42 no.6
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    • pp.1-12
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    • 2004
  • This study investigates residents' living satisfaction with high-rise, mixed-use apartments built in the structures of reinforced concrete construction(RC) and with steel framed, reinforced concrete construction(SRC). The following study results were obtained: 1) Residents expressed below average satisfaction (below 3.0) with the common-area landscape and environmentally-friendly factors, children's playground and its facilities, community service for residents' by the management offices and utility plan. 2) According to the satisfaction of sound environment, residents of the SRC group expressed above average satisfaction. It can be concluded that noise problems around the residential area of the SRC group was well solved in this study. However, the residents of the SRC group expressed low satisfaction with the freshness of indoor air, humidity, and smell in the living quarters. 3) High-rise, mixed-use apartments should accommodate a familial life cycle, be designed as an environmentally friendly resting place in harmony with city life, and provide various communal programs for residents.

The Residential Satisfaction of Residents in the High-rise Mixed-use Apartment (초고층 주상복합아파트 거주자의 주거만족도)

  • Lee, Soo-Hyun;Kang, Soon-Joo
    • Proceeding of Spring/Autumn Annual Conference of KHA
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    • 2003.11a
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    • pp.145-149
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    • 2003
  • This study is to investigate residents' living satisfaction with high-rise mixed-use apartment complexes built in the structures of the reinforced concrete constructing and the steel framed reinforced concrete construction. The results of this study were obtained as follows: 1. Residents expressed below average satisfaction (below 3.0) with the common-area landscape and environmentally-friendly factors, children's playground and its facilities, community service for residents' by the management offices and the plan of utility. 2.According to the satisfaction of sound environment, residents of SRC group expressed above average satisfaction; it can be concluded that problems of causing noise around the residential area of the SRC and S groups were well solved in this study. However, satisfaction with the freshness of indoor air, humidity, and smell in the living quarters was rated low by the residents of SRC group. 3. High-rise mixed-use apartment complexes should accomodate families's life cycle, design an environmentally-friendly resting place in harmony with city life, and provide various communal programs for residents.

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Properties of Adiabatic Temperature Rise of Concrete Using Different Types of Binder and Effects of Adiabatic Temperature on the Compressive Strength (결합재 종류에 따른 콘크리트의 단열온도상승특성 및 단열온도상승에 따른 압축강도특성에 관한 연구)

  • 하재담;김태홍;이종열;김진근
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.05a
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    • pp.527-532
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    • 2001
  • The crack of concrete induced by a temperature rise in early age concrete due to the heat of ration of cement is a serious problem for massive or high strength concrete structures. However, re is still no reasonable equations for the prediction of the temperature rising. On this study, the prediction equations of the heat of hydration of different types of binder are pained from the adiabatic temperature rise test, and compared with the results from different nations to obtain the best approximated equation. The strengths of concrete of which specimens were placed in the same chamber for the adiabatic to were compared with those under standard curing.

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Effect of Torsional Eccentricity on the Seismic Response of High-Rise RC Bearing-Wall Structures with Vertical Irregularity (고층 RC 벽식 비정형 구조물의 지진반응에 대한 비틀림 편심의 효과)

  • 고동우;이한선
    • Proceedings of the Korea Concrete Institute Conference
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    • 2003.05a
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    • pp.145-150
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    • 2003
  • The objective of this study is to investigate the effect of torsional eccentricity on the seismic response of high-rise RC bearing-wall structures with vertical irregularity. For this purpose, two 1:12 scale 17-story RC model structures, the one has concentric shear wall and the other has eccentric shear wall, were constructed and then subjected to a series of earthquake excitations. The test result shows the followings: 1) the layout of shear wall has the negligible effect on the natural period and the base shear coefficient, 2) the eccentric model behaves in the first and second mode while the concentric model has the first mode predominantly, 3) the stiff frame in the eccentric model resists most of overturning moment in the severe earthquake though both frames (the stiff and flexible frames) resist almost equally in the design earthquake.

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Thermal Crack Control about of LNG in Inchon (인천 LNG 지하탱크 Bottom 의 온도균열제어)

  • Koo, Bon-Chang;Ha, Sang-Wook;Kim, Dong-Seuk;Ha, Jae-Dam;Lee, Jong-Ryul;Kwon, Young-Ho
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.04a
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    • pp.291-296
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    • 2000
  • The crack of concrete induced by the heat of hydration is s serious problem, particularly in concrete structures such as bridge piers. thick walls, box type walls, mat-slab of nuclear reactor building, dams of foundations of high rise buildings, etc. As a result of the temperature rise and restriction condition of foundation, the thermal stress which way induce the cracks can occur. Therefore the various techniques of the thermal stress control in massive concrete have been widely used. One of them is prediction of the thermal stress, besides low-heat cement which mitigates the temperature rise, design change which consider steel bar reinforcement, operation control and so on. In this study, firstly it introduce the thermal cracks control technique by employing low-heat cement concrete, thermal stress analysis, Secondly it shows the application of the cracks control technique like the bottom of No.15,16 Underground LNG Tank in Inchon.

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