• Title/Summary/Keyword: 콘크리트충전강관

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A Study on Characteristics of Normal Strength Concrete adapted to Concrete Filled Steel Tube (콘크리트 충전강관구조(CFT) 적용을 위한 일반강도 콘크리트 물성에 관한 실험적 연구)

  • 강동현;강용학;정근호;이영도;이장오
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2001.11a
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    • pp.46-51
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    • 2001
  • As a rule, in case of CFT for high-rise building, high strength concrete is required since it should have high fluidity, segregation resistance and large proportion of cement per unit considering the fi11ing beneath the diaphragm. However, regarding the low-rise building under 20 stories, it is somewhat difficult to use high strength concrete. This is a fundamental study to develop a concrete with normal strength and high fluidity for CFT of low-rise building, whose purposes are in speculating several kinds of changes in concrete's characteristics through various experiments and offering basic documents for practicalization in si to and production through mock-up test.

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Experimental Study on Two-Seam Cold Formed Square CFT Column to Beam Connections with Asymmetric Diaphragms (상하 이형 다이아프램으로 보강된 2심 냉간성형 각형 CFT 기둥-보 접합부의 실험적 연구)

  • Oh, Heon Keun;Kim, Sun Hee;Choi, Sung Mo
    • Journal of Korean Society of Steel Construction
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    • v.25 no.1
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    • pp.35-45
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    • 2013
  • The concrete-filled tube column has the excellent structural performance. But it is difficult to connect with column and beam because of closed section. It suggests that pipe should be produced by welding two sides together where two shapes are joined after a channel is pre-welded onto the three sides in order to form an internal diaphragm. The upper diaphragm of the connection used the horizontal plate and the lower diaphragm used the Vertical plate. This research performed 6 monotonic tension experiments describing the connection upside and downside in order to evaluate the structural capability of the offered connection. And the cyclic loading experiment was performed about 2 T-Type column to beam connections. As to the experimental result edge cutting geometry, there was no big effect. An increase in the number of holes of the plate ultimate strength was increased by 5% and The thickness of the plate increases, the maximum strength was increased by 4%. T-Type connections until it reaches the plastic moment showed a stable behavior.

Resistance and Flexure Behavior of Slender Welded Built-up Square CFT Column Using Internal Reinforced Steel Tube under Eccentric Loads (강관내부 보강재를 고려한 용접조립 각형 CFT 편심 장주의 내력 및 휨 거동)

  • Lee, Seong-Hui;Kim, Young-Ho;Choi, Sung-Mo
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.6 no.2
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    • pp.32-39
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    • 2015
  • So far, square concrete filled tubular(CFT) columns have been used in a limited width thickness ratio. The reason is that local buckling occurs in steel tube easily. Once the local buckling occurs, the confinement effect of steel tube on concrete disappears. In this study, we developed welded built-up square steel tube with reinforcement which are placed at the center of the tube width acts as an anchor. 3 specimens of slender welded built-up square CFT columns and 3 specimens of slender welded built-up square steel tube columns were manufactured with parameters of width(B) of steel tube, width thickness ratio(B/t). we conducted a experimental test on the 6 specimens under eccentric load, and evaluated the structural resistance and behavior of 6 specimens.

An Experimental Study on the Structural Capacities of Steel-Concrete Column (Steel-Concrete Column의 구조성능에 관한 실험 연구)

  • Kim, Seong Jae;Park, Soon Jeon;Jeong, Sug Chang;Kim, Sang Dae
    • Journal of Korean Society of Steel Construction
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    • v.14 no.6
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    • pp.823-834
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    • 2002
  • Maximum-strength concrete-filled steel square tubular columns were tested under concentric and biaxial eccentric load. Buckling length-section depth ratio $L_k/D$, magnitude of eccentricity e, and angle of eccentric load ${\theta}$ were selected as experimental parameters. Strength and behavior were also examined. Test results showed that the maximum strength of columns under biaxial eccentric load could be predicted using the previously proposed strength formula of columns undr uniaxia eccentric load. Likewise, the behavior and maximum strength of columns could be predicted using the analysis.

The Shear Capacity of CFT Column to H-Beam End plate Connections with Penetrated High-Strength Bolts (관통형 고력볼트를 사용한 엔드플레이트형식 CFT 기둥-H형강 보 접합부의 전단성능)

  • Kim, Young Ju;Kim, Jae Keon;Oh, Young Suk;Moon, Tae Sup
    • Journal of Korean Society of Steel Construction
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    • v.12 no.4 s.47
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    • pp.351-362
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    • 2000
  • This paper is to study on the behavior of CFT column to H-beam end plate connections with penetrated high-strength bolts under cyclic load. The main parameters are as follows: 1) the thickness of end plate: 16mm, 22mm and 25mm, 2) the thickness of column : 9mm and 12mm. Comparison and analysis on the test results are performed in accordance with parameters. This study investigates energy absorption capacity of beam-column connections and analyzes the shear strength of joint panel. The shear strength of joint panel is estimated by superimposing the strength of the steel which is based on the von Mises yield criterion and that of the concrete which is used the Strut model to consider the effect of filled concrete.

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A Study on High Strength Concrete of Concrete Filled Steel Tube Column (CFT 기둥용 초고강도 충전콘크리트에 관한 연구)

  • Jung, Keun-Ho;Lim, Nam-Gi;Lee, Young-Do
    • Journal of the Korea Institute of Building Construction
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    • v.4 no.1
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    • pp.127-132
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    • 2004
  • CFT(Concrete Filled Steel Tube) is a structure of circular or squared of steel column filled with concrete. The steel tube holds the concrete inside and that makes this structure to perform superior features on stiffness, proof stress, transformation, fire resistance and construction itself. In this study, by over the 800kgf/$\textrm{cm}^2$ of high strength concrete for CFT column, research has been done on the basic property of matter such as fluidity, resistance on segregation, compressive strength, setting icons of the concrete filled in the steel tube under conditions of standard weather. Physical properties of concrete for CFT that Concrete with silica fume, fly ash of air entraining and high-range water reducing agent, that used to CFT column research purpose to find the most ideal composition, which is achieved by the investigation in the concrete's property of matter like ability of Slump, Slump Flow, Air content, Bleeding, and Settlement. For this study, experiments which are bused on obtained the result through physical test are practiced, with all of the experiment, specimens only for control are produced in each method of curing and analyzed to relations with core strength in mock-up test. In mock-up test, the research is studied compactability of concrete filled in tube and degree of hydration hysteresis, as a basic reference for applying to field of CFT column which is used over 800kgf/$\textrm{cm}^2$ high strength concrete.

Review of Structural Design Provisions of Rectangular Concrete Filled Tubular Columns (각형 콘크리트충전 강관기둥 부재의 구조설계기준 비교연구)

  • Lee, Cheol Ho;Kang, Ki Yong;Kim, Sung Yong;Koo, Cheol Hoe
    • Journal of Korean Society of Steel Construction
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    • v.25 no.4
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    • pp.389-398
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    • 2013
  • The structural provisions of rectangular CFT (concrete-filled tubular) columns in the 2005/2010 AISC Specification, ACI 318-08, and EC4 were comparatively analyzed as a preliminary study for establishing the unified standards for composite structures. The provisions analyzed included those related to the nominal strength, the effect of confinement, plate slenderness, effective flexural stiffness, and the material strength limitations. Small or large difference can be found among the provisions of AISC, ACI, and EC4. Generally, the 2010 AISC Specification provides the revised provisions which reflect up-to-date test results and tries to minimize the conflict with the ACI provisions. For example, the 2010 AISC Specification introduced a more finely divided plate slenderness limits for CFT columns. In seismic applications, the plate slenderness limits required for highly and moderately ductile CFT columns were separately defined. However, the upper cap limitations on material strengths in both the AISC and EC4 provisions are too restrictive and need to be relaxed considering the high-strength material test database currently available. This study found that no provisions reviewed in this paper provide a generally satisfactory method for predicting the P-M interaction strength of CFT columns under various material combinations. It is also emphasized that a practical constitutive model, which can reasonably reflect the stress-strain characteristics of confined concrete of rectangular CFT columns, is urgently needed for a reliable prediction of the P-M interaction strength.

An Alternative Perspective to Resolve Modelling Uncertainty in Reliability Analysis for D/t Limitation Models of CFST (CFST의 D/t 제한모델들에 대한 신뢰성해석에서 모델링불확실성을 해결하는 선택적 방법)

  • Han, Taek Hee;Kim, Jung Joong
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.28 no.4
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    • pp.409-415
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    • 2015
  • For the design of Concrete-Filled Steel Tube(CFST) columns, the outside diameter D to the steel tube thickness t ratio(D/t ratio) is limited to prevent the local buckling of steel tubes. Each design code proposes the respective model to compute the maximum D/t ratio using the yield strength of steel $f_y$ or $f_y$ and the elastic modulus of steel E. Considering the uncertainty in $f_y$ and E, the reliability index ${beta}$ for the local buckling of a CFST section can be calculated by formulating the limit state function including the maximum D/t models. The resulted ${beta}$ depends on the maximum D/t model used for the reliability analysis. This variability in reliability analysis is due to ambiguity in choosing computational models and it is called as "modelling uncertainty." This uncertainty can be considered as "non-specificity" of an epistemic uncertainty and modelled by constructing possibility distribution functions. In this study, three different computation models for the maximum D/t ratio are used to conduct reliability analyses for the local buckling of a CFST section and the reliability index ${beta}$ will be computed respectively. The "non-specific ${beta}s$" will be modelled by possibility distribution function and a metric, degree of confirmation, is measured from the possibility distribution function. It is shown that the degree of confirmation increases when ${beta}$ decreases. Conclusively, a new set of reliability indices associated with a degree of confirmation is determined and it is allowed to decide reliability index for the local buckling of a CFST section with an acceptable confirmation level.

Experimental Study on the Structural Behavior of Concrete-Filled Circular Tubular Column to H-Beam connections without Diaphragm (다이아프램이 없는 콘크리트 충전 원형강관 기둥-H형강 보 접합부의 구조적 거동에 관한 실험적 연구)

  • Kang, Hyun Sik;Moon, Tae Sup
    • Journal of Korean Society of Steel Construction
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    • v.9 no.1 s.30
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    • pp.13-22
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    • 1997
  • This paper is concerned with an experimental study on structural behavior of Concrete-Filled Circular Tubular(CFCT) column to H-beam connections. The important parameters are the number of inner reinforced rib and the width of H-beam flange(100, 150, 200mm) with variable column thickness(5.8mm, 9.2mm, 12.5mm) around the joint between CFCT and H-beam. Test results are summarized for the displacement, strength, initial stiffness, failure mode and energy absorption capacity of each specimen. The purpose of this paper is to investigate the initial stiffness and the strength of connections to evaluate the structural behavior of the CFCT column to H-beam connections. From the discussion about the test results, the basic data for non diaphragm connection design would be suggested.

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A Study on the Compression Behaviors of Concrete-filled Steel Tubular Columns (콘크리트 충전 강관기둥의 압축거동에 관한 연구)

  • Park, Kang-Geun;Yoon, Seoung-Hyun;Kim, Young-Tae
    • Journal of Korean Association for Spatial Structures
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    • v.1 no.2 s.2
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    • pp.67-74
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    • 2001
  • This paper is to estimate the load carrying capacities of concrete-filled steel tubular columns and the important parameters are selected the size, length and concrete strength. he concrete-filled tube structures has many excellent structural properties, that is, high load capacity, good plastic deformation and high resistance local buckling. Under these background, this study Investigated to the structural compression behaviors, the maximum strength, the confinement effects, the fracture mechanism, local buckling failure and concrete strength effects.

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