• Title/Summary/Keyword: Concrete Filled Tubular

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Analysis of concrete-filled steel tubular columns with "T" shaped cross section (CFTTS)

  • Wang, Qin-Ting;Chang, Xu
    • Steel and Composite Structures
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    • v.15 no.1
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    • pp.41-55
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    • 2013
  • This paper presents a numerical study of axially loaded concrete-filled steel tubular columns with "T" shaped cross section (CFTTS) based on the ABAQUS standard solver. Two types of columns with "T" shaped cross section, the common concrete-filled steel tubular columns with "T" shaped cross section (CCFTTS) and the double concrete-filled steel tubular columns with "T" shaped cross section (DCFTTS), are discussed. The failure modes, confining effects and load-displacement curves are analyzed. The numerical results indicate that both have the similar failure mode that the steel tubes are only outward buckling on all columns' faces. It is found that DCFTTS columns have higher axial capacities than CCFTTS ones duo to the steel tube of DCFTTS columns can plays more significant confining effect on concrete. A parametric study, including influence of tube thickness, concrete strength and friction coefficient of tube-concrete interface on the axial capacities is also carried out. Simplified formulae were also proposed based on this study.

Non-linear Behavior of New Type Girder Filled by High-Strength Concrete (신형식 거더의 고강도 콘크리트 적용 시 비선형 거동 분석)

  • Choi, Sung-Woo;Lee, Hak;Kong, Jung-Sik
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.217-220
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    • 2008
  • Recently, many studies about a high-strength concrete and composite structures are being progressed to get the more economic and stable result in the construction of structure all over the world. One of those studies is about CFTA(Concrete Filled and Tied Steel Tubular Arch) girder that applies an arch structure and a pre-stressed structure to CFT(Concrete Filled Steel Tubular) Structure which is filled with a concrete and improve the stiffness and strength of the structure by the confinement effect of fillers to maximize the efficiency of structure and economic. In this study, non-linear behavior of CFTA girders filled with a general concrete and the high-strength concrete respectively were analyzed by using ABAQUS 6.5-1 and results were compared.

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Behavior of Concrete-Filled and Tied Steel Tubular Arch Girder (콘크리트 충전 타이드 아치형 강재 합성거더의 선형 거동 분석)

  • Lee, Hak;Park, Ho;Lee, Eun-Ho;Kim, Jung-Ho;Kong, Jung-Sik
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2007.04a
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    • pp.688-693
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    • 2007
  • Nowadays various studies related with superstructure of bridges are developed and they pursuit more effective section of bridges superstructure, material and economical application of composite materials. CFT structure(Concrete Filled Steel Tubular Structure) is developed type of composite structure that concrete is filled with steel box, and the deformation of the member, stiffness and internal force will be improved by confinement effect of steel box and concrete. This paper introduces new type of girder, CFTA girder( Concrete- Filled and Tied Steel Tubular Arch Girder) which is combined with traditional CFT structure,arch effect and prestress through carrying out the structural analysis by computer programs. The computer programs which is used are ABAQCS and MIDAS, and the 12.2m girder which is applied same load and prestresses is analyzed and compared the results respectively.

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Experimental study on partially concrete-filled steel tubular columns

  • Ishizawa, T.;Nakano, T.;Iura, M.
    • Steel and Composite Structures
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    • v.6 no.1
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    • pp.55-69
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    • 2006
  • The results of tests conducted on 11 concrete-filled steel tubular columns were reported. Concrete was partially filled in circular steel tubular columns. The primary test parameters were radius and thickness of steel tubes, concrete height, loading patterns and attachment of diaphragm and studs. Concrete strain was measured directly by embedding strain gauges so that the effect of diaphragm on concrete confinement could be investigated. The effects of concrete height and diaphragm on ultimate strength and ductility of steel tubes were investigated. The comparisons of the test results with the existing results for rectangular cross-sections were made on the basis of ultimate strength and ductility of concrete-filled steel tubular columns.

Experimental Study on Compressive Strength of Centrally Loaded Concrete Filled Square Tubular Steel Columns (중심축압(中心軸壓)을 받는 콘크리트충전(充塡) 각형강관(角形鋼管)기둥의 내력(耐力)에 관한 실험적(實驗的) 연구(硏究))

  • Kim, Jong Sung;Oh, Yun Tae;Kwon, Young Hwan
    • Journal of Korean Society of Steel Construction
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    • v.8 no.4 s.29
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    • pp.59-76
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    • 1996
  • Concrete filled steel tube column has a large load carrying capacity through its steel and concrete interaction which makes it useful in construction. However, it has not been used often in a practical construction field. This is partly due to the non-destructive inspection method for concrete filling which has yet to be established. Furthermore, there are the lack of test data and a practical method in evaluating the ultimate load carrying capacity of concrete filled steel tube column. This paper will attempt to predict the ultimate strength of short concrete filled square tubular steel columns through conducting several tests. To accumulate the new test data on concrete filled steel tube columns, a total of 42 specimens of steel tubular columns were monotonically tested under concentric axial force, having the slenderness ratio(${\lambda}=10,\;15,\;20$), width-thickness ratio(d/t=25.0, 33.3) and concrete strengths($F_{c}=210,\;240,\;270kg/cm^{2}$). The hollow sections and concrete filled steel columns were compared to check the lateral confinded effects by steel tube. Through these test results, we propose a coefficient k=3.64 for the strength evaluation formula(10) of concrte filled tubular steel short columns.

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Fire resistance of high strength concrete filled steel tubular columns under combined temperature and loading

  • Tang, Chao-Wei
    • Steel and Composite Structures
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    • v.27 no.2
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    • pp.243-253
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    • 2018
  • In recent years, concrete-filled box or tubular columns have been commonly used in high-rise buildings. However, a number of fire test results show that there are significant differences between high strength concrete (HSC) and normal strength concrete (NSC) after being subjected to high temperatures. Therefore, this paper presents an investigation on the fire resistance of HSC filled steel tubular columns (CFTCs) under combined temperature and loading. Two groups of full-size specimens were fabricated to consider the effect of type of concrete infilling (plain and reinforced) and the load level on the fire resistance of CFTCs. Prior to fire test, a constant compressive load (i.e., load level for fire design) was applied to the column specimens. Thermal load was then applied on the column specimens in form of ISO 834 standard fire curve in a large-scale laboratory furnace until the set experiment termination condition was reached. The results demonstrate that the higher the axial load level, the worse the fire resistance. Moreover, in the bar-reinforced concrete-filled steel tubular columns, the presence of rebars not only decreased the spread of cracks and the sudden loss of strength, but also contributed to the load-carrying capacity of the concrete core.

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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An experimental study on th reinforced concrete filled tubular column to steel H-beam connections with outer diaphram by simplified connection type (철근콘크리트충전 강관기둥과 외부다이아프램을 보강한 H형강 보 접합부의 단순모형에 의한 실험연구)

  • 김인덕;최병극;박성무
    • Proceedings of the Korea Concrete Institute Conference
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    • 1997.10a
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    • pp.587-596
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    • 1997
  • This study is concerning the structural behavior of reinforced concrete filled tubular column to steel H-beam connections with outer diaphram by simplified connection type. The important parameters of this study are the cross-section shape of tubular column and the spacing of hoop (60mm, 30mm, 20mm) and the concrete filled or not. The experimental results are summarized for the strength and displacement of each specimen.

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Experimental study on reinforced concrete filled circular steel tubular columns

  • Hua, Wei;Wang, Hai-Jun;Hasegawa, Akira
    • Steel and Composite Structures
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    • v.17 no.4
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    • pp.517-533
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    • 2014
  • Experimental results of 39 specimens including concrete columns, RC columns, hollow steel tube columns, concrete filled steel tubular (CFT) columns, and reinforced concrete filled steel tubular (RCFT) columns are presented. Based on the experimental results, the load-carrying capacity, confined effect, ductility, and failure mode of test columns are investigated. The effects of the main factors such as width-thickness ratio (the ratio of external diameter and wall thickness for steel tubes), concrete strength, steel tube with or without rib, and arrangement of reinforcing bars on the mechanical characteristics of columns are discussed as well. The differences between CFT and RCFT are compared. As a result, it is thought that strength, rigidity and ductility of RCFT are improved; especially strength and ductility are improved after the peak of load-displacement curve.

Failure of lightweight aggregate concrete-filled steel tubular columns

  • Ghannam, Shehdeh;Jawad, Yahia Abdel;Hunaiti, Yasser
    • Steel and Composite Structures
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    • v.4 no.1
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    • pp.1-8
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    • 2004
  • Tests on steel tubular columns of square, rectangular and circular section filled with normal and lightweight aggregate concrete were conducted to investigate the failure modes of such composite columns. Thirty-six full scale columns filled with lightweight and normal weight aggregate concrete, eighteen specimens for each, were tested under axial loads. Nine hollow steel sections of similar specimens were also tested and results were compared to those of filled sections. The test results were illustrated by a number of load-deflection and axial deformation curves. The results showed that both types of filled columns failed due to overall buckling, while hollow steel columns failed due to bulging at their ends (local buckling). According to the above-mentioned results, and due to low specific gravity and thermal conductivity of the lightweight concrete the further interest should be concentrated in replacing the normal concrete by the lightweight aggregate concrete.