• Title, Summary, Keyword: 콘크리트충전 강합성 기둥

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A Study on the Ductility of Concrete-Filled Composite Columns under Cyclic Loading (반복하중을 받는 콘크리트충전 강합성 기둥의 연성에 관한 연구)

  • 송준엽;권영봉;김성곤
    • Journal of the Earthquake Engineering Society of Korea
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    • v.5 no.6
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    • pp.11-19
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    • 2001
  • A series of test on concrete-filled composite columns was preformed to evaluate structural performance under axial compression and cyclic lateral loading. It was presented that concrete-filled composite columns had high strength, high stiffness and large energy-absorption capacity on account of mutual confinement between the steel plate and filled-in concrete. A cross section analysis procedure developed to predict the moment-curvature relation of composite columns was proven to be on accurate and effective method. The ductility factor and the response modification factor were evaluated for the seismic design of concrete-filled composite columns. It was shown that concrete-filled composite columns could be used as a very efficient earthquake-resistant structural member.

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Eccentric Axial Load Test for Concrete-Filled Tubular Columns Encased with Precast Concrete (프리캐스트 콘크리트에 의해 피복된 콘크리트충전 강관기둥의 편심압축실험)

  • Lee, Ho Jun;Park, Hong Gun;Kim, Sung Bae;Park, Sung Soon
    • Journal of Korean Society of Steel Construction
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    • v.26 no.1
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    • pp.31-42
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    • 2014
  • In this paper, concrete-filled steel tubular columns encased with precast reinforced concrete were studied. Four eccentrically loaded columns and a concentrically loaded column were tested to investigate the axial load-carrying capacity. The test parameters were the use of fiber reinforcement for cover concrete, eccentricity, column length, and lateral reinforcement. The maximum axial loads of the specimens agreed with the nominal strengths predicted by KBC 2009. However, in some specimens, the load carrying capacity quickly decreased after the peak strength due to spalling of the cover concrete.

The Specified Minimum Yield Stress of SM570TMC in CFT Composite Columns (SM570TMC강을 이용한 콘크리트충전강관 합성기둥의 설계기준 항복강도)

  • Lee, Myung Jae
    • Journal of Korean Society of Steel Construction
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    • v.20 no.1
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    • pp.205-213
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    • 2008
  • The objective of this study is to evaluate the yield stress of SM570TMC CFT column subject to axial force. These columns were evaluated and compared by statistical tests, during which the displacements and axial loads of column specimens were measured. Test results showed that the yield stress of CFT columns under axial load could be predicted using the previously proposed the yield stress of steel columns.

Investigation of Shear Design Expressions of Large-Diameter Concrete-Filled Steel Tubes(CFT) (대구경 콘크리트 충전형 합성기둥의 전단 설계식 분석)

  • Jung, Eun Bi;Yeom, Hee Jin;Yoo, Jung Han
    • Journal of Korean Society of Steel Construction
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    • v.27 no.4
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    • pp.399-410
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    • 2015
  • Concrete filled steel tube(CFT) has outstanding deformation capacity and strength in comparison with reinforced concrete or steel tube. CFT drilled shaft, which is developed large shear force due to seismic load and soil liquefaction, is designed as large diameter. However, shear design equations of the current standards do not consider bond stress of CFT and it results in extremely conservative design. Currently, previous studies for improving shear equations scarcely exist and are impossible applied to large CFT drilled shafts since these studies focus on only small scale experimental research. In this study, eventually to propose improving shear equation of large diameter CFT, it is preliminary research to compare and investigate the previous studies and current standards.

Structural Behavior Analysis of Concrete Encased and Filled tube Square Column with Construction Sequence (시공단계를 고려한 피복충전형 콘크리트충전 각형기둥의 구조적 거동 분석)

  • Kim, Sun Hee;Yom, Kong Soo;Choi, Sung Mo
    • Journal of Korean Society of Steel Construction
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    • v.27 no.1
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    • pp.43-52
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    • 2015
  • Constructions of buildings downtown are increasing as much as ever with a strong demand. Top-Down Method is suitable for its advantage in minimizing its disturbance to the neighborhood. Pre-founded when applied to CFT Column on-site welded is required for splicing. To complement the welded built-up square composite Column was developed. Top-down process will be pouring concrete in accordance with a step-by-step process. Thus, Pre-founded Column and cover concrete to determine the stress condition. Therefore, Concrete filled steel square tubular columns encased with precast concrete were studied. Five Centrally loaded Columns were tested to investigate the axial load carrying capacity. we analyzed the strength and behavior of CET Column by Loading conditions and concrete strength, thickness of cover concrete through structure experiments.

The Evaluation of the Axial Strength of Composite Column with HSA800 Grade Steel (HSA800 강재를 적용한 합성기둥의 축방향 내력 평가)

  • Lee, Myung Jae;Kim, Cheol Hwan;Kim, Hee Dong
    • Journal of Korean Society of Steel Construction
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    • v.26 no.5
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    • pp.473-483
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    • 2014
  • According to the Korean Building Code (KBC), the validity of the application of 800MPa grade steel(HSA800) to composite column should be verified by experimental or analytical method. Thus, stub column tests for encased and filled composite members with HSA800 steel were conducted, and axial strength and the validity of design compressive strength equations in KBC were evaluated. The test results show that the equation of the compressive strength of encased composite column member in KBC should be modified in order to use HSA800 steel without any reduction of specified minimum yield strength. For this purpose, it is suggested that the interval of hoop should be narrowed and the effective concrete area should be used. The equation of the compressive strength of filled composite column member in KBC is applicable to filled composite column with HSA800 steel without any modification.

Analysis Study on Fire Performance with Internal Anchored Concrete Filled Steel Tube Columns According to Percent of Steel-Fibers (강섬유 콘크리트 혼입율에 따른 내부앵커형 콘크리트 충전기둥 내화성능에 관한 해석적 연구)

  • Kim, Sun Hee;Yom, Kong Soo;Kim, Yong Hwan;Choi, Sung Mo
    • Journal of Korean Society of Steel Construction
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    • v.28 no.1
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    • pp.23-34
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    • 2016
  • Concrete filled steel tube system has two major advantages. First, the confinement effect of steel tube improves the compressive strength of concrete. Second, the load capacity and deformation capacity of members are improved because concrete restrains local buckling of steel tube. It does, however, involve workability problem of using stud bolts or anchor bolts to provide composite effect for larger cross-sections. While the ribs inside the columns are desirable in terms of compressive behavior, they cause the deterioration in load capacity upon in-plane deformation resulting from thermal deformation. Since the ribs are directly connected with the concrete, the deformation of the ribs accelerates concrete cracking. Thus, it is required to improve the toughness of the concrete to resist the deformation of the ribs. Welding built-up tubular square columns can secure safety in terms of fire resistance if the problem are solved. This study focuses on mixing steel fiber in the concrete to improve the ductility and toughness of the columns. In order to evaluate fire resistance performance, loaded heating test was conducted with 8 specimens. The behavior and thermal deformation capacity of the specimens were analyzed for major variables including load ratio. The reliability of heat transfer and thermal stress analysis model was verified through the comparison of the results between the test and previous study.

Evaluation on Deformation Capacity of CFT Square Columns subject to Constant Axial and Cyclic Lateral Loads (일정축력과 반복 수평력을 받는 콘크리트충전 각형강관 기둥의 변형성능 평가)

  • Ji, Ku Hyun;Choi, Sung Mo;Kim, Dong Kyu
    • Journal of Korean Society of Steel Construction
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    • v.12 no.2
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    • pp.209-219
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    • 2000
  • Concrete Filled steel Tube(CFT) Column has an excellent structural capacities in accordance with an interaction effect between the steel tube and concrete. Recently, CFT structure has been focussed on a structural system for a high-rise buildings. The purpose of this study is to evaluate a strength and deformation capacity of CFT square columns subjected to constant axial and cyclic lateral load. The test parameters are diameters to thickness ratio of steel tube, axial load ratios, concrete strengths, load applying types and whether or not filled concrete. Total sixteen specimens are fabricated to clarify the energy absorbtion capacity of CFT columns. Experimental results are summarized for maximum strength, initial stiffness and deformation capacity.

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Behavior of Concrete-Filled Square Tubular Beam-Column under Cyclic Load (반복하중을 받는 콘크리트충전 각형강관 보-기둥의 거동)

  • Kang, Chang-Hoon;Moon, Tae-Sup
    • Journal of Korean Society of Steel Construction
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    • v.12 no.4
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    • pp.387-395
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    • 2000
  • The purpose of this research is to evaluate the capacity of strength and plastic deformation of those members, and provide experimental data on the seismic behavior of these members as a basis for developing guidelines for designing seismically resistant concrete-filled steel tubular columns. Eighteen cantilever-type specimens were tested under constant axial load and cyclically lateral load as models of bottom columns in high-rise building. The parameters studied in the test program included, are width-thickness ratio of steel tube, slenderness ratio (Lo/D) and axial force ratio. From the test results, the effects of parameters on the strength, the deformation capacity, energy absorption capacity are discussed. The specimen flexural capacity under combined axial and lateral loading was found to be almost accurately predicted by criteria AIJ and AISC-LRFD providing conservative results. Therefore KSSC for encased composite column can be applied to the concrete filled column if composite section and elastic modulus are modified according to AIJ and AISC-LRFD. Finally, the proposed flexural capacity considering confinement effects is a food agreement on the tests results.

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A Parametrical Study on the flexural strength of Concrete-Filled SHS Columns to Composite H-Beam Connections (충전각형강관 기둥-합성 H형강보 접합부 휨성능 결정요인에 관한 연구)

  • Lee, Jong Seok
    • Journal of Korean Society of Steel Construction
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    • v.11 no.4
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    • pp.385-395
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    • 1999
  • Square hollow section columns and H-section beams have recently been increasing1y used. Rigid column-beam connections cannot be made for the structural system and thus some measures to improve the rotational stiffness of connections should be developed. For this purpose, several types of connections. such as H-section beams connected to concrete-filled square hollow section columns, have been contrived and put to experiment. Since the experimental works are usually difficult and expensive. Particularly test of all the types of connections with similar behavior may not be feasible. Instead, the numerical analysis will be adopted predict the flexural stiffness of connections. In this work, FEM modeling techniques are examined and parametric analysis study has been carried out. The major parameters considered are concrete strength, thickness of steel column, magnitude and eccentricity of axial forces.

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