• Title/Summary/Keyword: 콘크리트 충전

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An Experimental Study on Stength of Slender Square Tube Columns Filled with High Strength Concrete (고강도콘크리트충전 각형강관장주의 내력에 관한 실험적 연구)

  • Seo, Seong Yeon;Chung, Jin An
    • Journal of Korean Society of Steel Construction
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    • v.14 no.4
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    • pp.471-479
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    • 2002
  • In this paper, 18 square CFT columns filled with high-strength concrete were tested under concentric or eccentric axial loading. Two parameters of the experimental program included the buckling length-section depth ratio ($L_K$/D) and the eccentricity of the appled compressive load (e). In additon, mechanical properties such as the compressive concrete strength and compressive and tensile steel strength were measured and incorporated into the material models for the stress-strain relationships of concrete and steel. This model was used in an elasto-plastic analysis in order to predict the behavior of the slender CFT columns. Observtions of the failure mode during the tests under axial loadig were also presented. The strengths obtained from the analysis. Recommendations for Design, and Constructions of CFT structures were presented, as verified by the experimental results.

An Analytical Investigation on the Ultimate Strength of Concrete-Filled Steel Tube Columns using Elasto-Plastic Large Deformation Analysis (탄소성 대변형 해석을 이용한 콘크리트 충전강관(CFT) 기둥의 극한강도에 관한 해석적 연구)

  • Jang, Gab-Chul;Chang, Kyong-Ho
    • Journal of Korean Association for Spatial Structures
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    • v.7 no.6
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    • pp.69-74
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    • 2007
  • Recently, to improve performance and strength of circular steel columns, application of concrete-filled steel tube(CFT) type are gradually increased. To accurately predict the plastic design of concrete-filled steel tube columns, a plasticity model is required which can be describe large deformation behavior of concretes and steels. In this study, elastic-plastic large deformation analysis is developed by using the plasticity model of structural steels, and accurate and validity of the developed program is verified by comparing between the experiment and the analysis for concrete-filled steel tube column. In concrete-filled steel tube columns, influence of initial deflection on ultimate strength behavior is investigated by using developed program.

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Experimental Study on the Infilling Characteristics of CFT Column Infilled by Pumping-Up Below (하부압입공법에 의한 콘크리트 충전강관(CFT)기둥의 충전특성에 관한 실험적 연구)

  • Kim, Myoung Mo;Jeon, Sang Woo
    • Journal of Korean Society of Steel Construction
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    • v.14 no.2
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    • pp.375-383
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    • 2002
  • To evaluate the applicability of the construction method involving infilling CFT columns by pumping-up, a trial construction was done using 6 actual size test samples. The 12.8m-high test samples were similar to a four-story building scale. The pumping-up level was controlled at 12m. The test used two types of high performance concrete with $450kgf/cm^2$ standard design strength, and a concrete pump which is used domestically. The pressure changes in pipes or pump as well as the changes in concrete characteristics were measured during construction. in order to evaluate applicability. After the concrete hardened, the column was dismantled. The filled state of the concrete, concrete strength distribution according to column height, etc., were checked to evaluate the quality of the concrete, From the results, some basic data which characterize the pumping-up pressure were suggested. Also, the strength of hardened concrete as well as the filled state were proven to be acceptable ranges.

Interface Behavior of Concrete Infilled Steel Tube Subjected to Flexure (휨을 받는 콘크리트 충전 강관의 계면거동)

  • Lee, Ta;Jeong, Jong-Hyun;Kim, Hyeng-Ju;Lee, Yong-Hak
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.35 no.1
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    • pp.9-17
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    • 2015
  • Interface behavior of concrete-infilled steel tube (CFT) was investigated based on the experimental observations and numerical analyses. Laboratory tests were performed for twelve CFTs that consisted of two different cases of diameters where each diameter case was composed of three different cases of shear span length. Thereby, diameter and shear span parameters were considered to prove the question of whether there exists interface slip between steel tube and infilled-concrete. Confining effect of steel tube to infilled concrete was also investigated by measuring lateral strain as well as longitudinal strain. Based on the study, it was concluded that confining effect of steel tube to infilled-concrete is not influential under flexural loading and therefore, the sectional analysis is an effective way to estimate the flexural strength of CFT.

Strength of Concrete-Filled Rectangular Steel Tubular Columns (콘크리트 충전 각형강관 기둥의 내력 평가)

  • Yoo, Yeong Chan;Moon, Tae Sup
    • Journal of Korean Society of Steel Construction
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    • v.11 no.1 s.38
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    • pp.89-98
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    • 1999
  • The objective of this paper is to investigate the structural behavior of concrete filled steel tubular columns subjected to eccentric load. With experiment and analytical study, the buckling behavior of columns is investigated and compared with each other to the view of main parameters. Appling foreign standards in the experimental results, we suggested new strength formula of concrete-filled steel tubular columns. The parameters are slenderness, eccentric ratio, and concrete filled or not. The experiment are carried out by simple loading.

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Mechanical Properties of the High Flowing Self-Compacting Concrete for Members of Bridge Overcrowded Arrangement of Bar (과밀 배근된 교량 부재용 초유동 자기충전 콘크리트의 역학적 특성)

  • Choi, Yun-Wang;Kim, Yong-Jic;Kang, Hyun-Jin
    • Journal of the Korea Concrete Institute
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    • v.20 no.2
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    • pp.175-183
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    • 2008
  • Domestically, application of High Flowing Self-Compacting Concrete (HSCC) is limited to building structures and it is difficult to find examples of application in civil infrastructural constructions. However, in the case of North America and Europe, by introducing precast and prestressed system, HSCC is being used for high-density reinforced bridge members. Hence it is assessed that broadening the utilization of HSCC into areas such as bridges and civil construction is required. Therefore in this research, to apply HSCC to high-density reinforced bridge members, ground granulated blast-furnace slag and fly ash were mixed in binary and ternary systems. Also the dynamical characteristics of HSCC, following 1st class regulations of Japan Society of Civil Engineers (JSCE), were assessed to enable application on high-density reinforced structures. The test results revealed ternary system mixture showed better mechanical characteristics than binary system mixture and the application on high-density reinforced precast bridge members seems possible.

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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The Evaluation of Seismic Performance for Concrete-filled Steel Piers (콘크리트 충전 강교각의 내진 성능 평가)

  • 정지만;장승필;인성빈
    • Journal of the Earthquake Engineering Society of Korea
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    • v.6 no.5
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    • pp.53-58
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    • 2002
  • A recent development, a concrete-filled steel(CFS) pier is an alternative to a reinforced concrete bridge pier in an urban area, because of its fast construction and excellent ductility against earthquakes. The capacity of CFS piers has not been used to a practical design, because there is no guide of a seismic design for CFS piers. Therefore, the guide of a seismic design value is derived from tests of CFS piers in order to apply it to a practical seismic design. Steel piers and concrete-filled steel piers are tested with constant axial load using quasi-static cyclic lateral load to check ductile capacity and using the real Kobe ground motion of pseudo-dynamic test to verify seismic performance. The results prove that CFS piers have more satisfactory ductility and strength than steel piers and relatively large hysteretic damping in dynamic behaviors. The seismic performance of steel and CFS piers is quantified on the basis of the test results. These results are evaluated through comparison of both the response modification factor method by elastic response spectrum and the performance-based design method by capacity spectrum and demand spectrum using effective viscous damping. The response modification factor of CFS piers is presented to apply in seismic design on a basis of this evaluation for a seismic performance.

The Quality Properties of Self Consolidating Concrete Using Lightweight Aggregate (경량골재를 사용한 자기충전 콘크리트의 품질 특성)

  • Kim, Yong Jic;Choi, Yun Wang
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.30 no.6A
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    • pp.573-580
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    • 2010
  • This paper presents the development of self-consolidating concrete (SCC) using lightweight aggregates. SCC using Lightweight aggregate properties have been evaluated in terms of flowability, segregation resistance and filling capacity of fresh concrete as per the standards of the Japanese Society of Civil Engineering (JSCE). The measurement of the mechanical properties of hardened SCC using lightweight aggregate, including compressive strength, splitting tensile strength, elastic moduli and density, as well as its dry shrinkage and carbonation properties were also carried out. The characteristics of SCC using lightweight aggregate at the fresh state showed that as the use of the lightweight aggregate, the flowability improves without exception of Mix No. 9 but the segregation resistance tends to decrease without exception of Mix No. 3, 4 and 5. The 28 days compressive strength of the SCC using lightweight aggregate was found to be 30 MPa or higher. The relationship between the compressive strength and the splitting tensile strength was found to be similar to the expression presented by CEB-FIP, and the relationship between the compressive strength and the elastic moduli was found to be similar to the expression suggested by ACI 318-08 which takes into consideration the density of concrete. The density of the SCC using lightweight aggregate decreased by up to 26% compared to that of the control SCC. Also, The dry shrinkage and carbonation depth of the SCC using lightweight aggregate increased compared to that of the control SCC.

Basic Research of Self Compacting Concrete Using Alkali-Activated Slag Binder (알칼리 활성 슬래그 결합재를 이용한 자기충전 콘크리트의 기초 연구)

  • Song, Keum-Il;Shin, Gyeong-Sik;Gong, Min-Ho;Song, Jin-Kyu
    • Journal of the Korea Concrete Institute
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    • v.25 no.6
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    • pp.657-665
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    • 2013
  • The purpose of this study is the basic research of self-compacting concrete using Alkali-Activated Slag (AAS) binder in order to emphasize the durability of structures and facilitate casting the fresh concrete in field. The AAS binder emitted low carbon dioxide ($CO_2$) is eco friendly material of new concept because AAS products not only emit little $CO_2$ during production but also reuse the industrial by-products such as ground granulated blast-furnace slag (GGBS) of the steel mill. Until now, almost of domestic and foreign research are using Ordinary Portland Cement (OPC) for self-compacting concrete, and also, nonexistent research about AAS. The self-compacting concrete must get the performance of flowability, segregation resistance, filling and passing ability. Nine concrete mixes were prepared with the main parameter of unit amount of binder (400, 500, 600 $kg/m^3$) and 3 types of water-binder (W/B) ratio. The results of test were that fresh concretes were satisfied with flowability, segregation resistance, and filling ability of JSCE. But the passing ability was not meet the criteria of EFNARC because of higher viscosity of AAS paste than OPC. This high viscosity of AAS paste enables the manufacturing of self compacting concrete, segregation of which does not occur without the using of viscosity agent. It is necessary that the development of high fluidity AAS binders of higher strength and the study of better passing ability of AAS concrete mixes in order to use self compacting AAS concrete in field.