• Title, Summary, Keyword: column tube

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Experimental research on load-bearing capacity of cast steel joints for beam-to-column

  • Han, Qinghua;Liu, Mingjie;Lu, Yan
    • Structural Engineering and Mechanics
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    • v.56 no.1
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    • pp.67-83
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    • 2015
  • The load transfer mechanism and load-bearing capacity of cast steel joints for H-shaped beam to square tube column connection are studied based on the deformation compatibility theory. Then the monotonic tensile experiments are conducted for 12 specimens about the cast steel joints for H-shaped beam to square tube column connection. The findings are that the tensile bearing capacity of the cast steel joints for beam-column connection depends on the ring of cast steel stiffener. The tensile fracture happens at the ring of the cast steel stiffener when the joint fails. The thickness of square tube column has little influence on the bearing capacity of the joint. The square tube column buckles while the joint without concrete filled, but the strength failure happens for the joint with concrete filled column. And the length of welding connection between square tube column and cast steel stiffener has little influence on the load-bearing capacity of the cast steel joint. Finally it is shown that the load-bearing capacity of the joints for H-shaped beam to concrete filled square tube column connection is larger than that of the joints for H-shaped beam to square tube column connection by 10% to 15%.

Ductility Characteristics of a Hollow R.C Pier Internally Confined by a Corrugated Steel Tube (파형강관으로 내부구속된 중공 R.C 교각의 연성도)

  • Han Taek Hee;Kim Sung Nam;Kang Young Jong;Jung Doo-Suk
    • Proceedings of the KSR Conference
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    • pp.712-717
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    • 2005
  • When the weight if a concrete member makes problems, or when the cost of the concrete is relatively high, it may be economical to use a hollow concrete member. But a hollow R.C column may have poor ductility because of the brittle failure at the inner face of the hollow R.C column. This brittle failure results from the absence of the confinement at the inner face of the hollow R.C column. To avoid this brittle failure an internally confined hollow R.C column by a steel tube was developed before. In this study, a hollow R.C column is internally confined by a corrugated steel tube instead of a general flat steel tube. And a column ductility is performed. Test results show that the energy ductility ratio of a internally confined hollow R.C column by a by a corrugated steel tube corresponds to $80\%$ of the energy ductility ratio of a general solid R.C column.

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Emission Characteristics of Discharge Tube with Mixed Gases

  • Jo, Ju-Ung;Park, Yong-Sung;Lee, Jong-Chan;Masaharu Aono;Park, Dae-Hee
    • KIEE International Transactions on Electrophysics and Applications
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    • v.3C no.4
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    • pp.136-139
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    • 2003
  • The positive column of a discharge tube filled with a mixture of mercury-xenon has a tendency to become contracted at room temperature. However, once the tube temperature is raised over 50 [$^{\circ}C$], the positive column changes from a contracted state to a diffused state. The xenon emission is stronger in the contracted positive column than in the diffused column. Alternatively, the mercury emission is more intense in the diffused positive column, and the luminance of the phosphor coating on the inner surface of the tube is higher than that in the contracted positive column. Moreover, higher luminance can be obtained by increasing the xenon pressure.

Behavior of Hybrid Double Skin Concrete Filled Circular Steel Tube Columns

  • Kim, Jin-Kook;Kwak, Hyo-Gyoung;Kwak, Ji-Hyun
    • Steel and Composite Structures
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    • v.14 no.2
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    • pp.191-204
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    • 2013
  • A hybrid double skin concrete filled (HDSCF) circular steel tube column is proposed in this study. The yield strength of the outer steel tube is larger than 690MPa and the inner tube has less strength. In order to achieve efficiency with the high strength outer tube, a feasibility study on reducing the thickness of the tube below the specified design codes for CFTs was conducted based on an experimental approach. The experiment also took variables such as thickness of the inner tube, hollow ratio, and strength of concrete into consideration to investigate the behavior of the HDSCF column. In order to estimate the applicability of design equations for CFTs to the HDSCF column, test results from CFT and HDSCF columns with design codes were compared. It was found that the axial compressive performance of the proposed HDSCF column is equivalent to that of the conventional CFT member irrespective of design variables. Furthermore, the design equation for a circular CFT given by EC4 is applicable to estimate the ultimate strength of the HDSCF circular steel tube column.

Analytical Study on the Fire Resistance of Internally Confined Hollow CFT Column (내부 구속 중공 CFT 기둥의 내화 성능에 대한 해석 연구)

  • Won, Deok Hee;Han, Taek Hee;Park, Jong Sup;Kim, Young Jong
    • Journal of Korean Society of Steel Construction
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    • v.21 no.5
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    • pp.461-470
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    • 2009
  • A column resisting axial load and seismic load is one of the main members in a structural system. The heated column by event of a fire can lose its strength and it may damage its structural system or cause the collapse of the entire structural system. In this study, the fire resistance capacity of internally confined hollow concrete filled tube (ICH CFT) column was investigated. In an ICH CFT column, the yield strength of the external tube is important as a concrete filled tube (CFT) column because the external tube confines the filled concrete and the strength of the column depends on the confined effect. A study was performed by finite element analyses considering the confined effect and material nonlinearity as the temperature changes by the fire. The hollow ratio, the thickness of the external tube, and the strength of concrete were selected as the parameters for the analyses. The analyses were performed by using a commercial FEA program (ABAQUS) and nonlinear concrete model program. The analysis results showed that the hollow ratio and the strength of concrete mainly affect the fire resisting capacity of an ICH CFT column.

Seismic behavior of steel tube reinforced concrete bridge columns

  • Tian, Tian;Qiu, Wen-liang;Zhang, Zhe
    • Steel and Composite Structures
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    • v.28 no.1
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    • pp.63-71
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    • 2018
  • This paper reports an experimental study that was accomplished to assess the seismic behavior of steel tube reinforced concrete bridge columns (SBCs). The motivation of this study was to verify a supposition that the core steel tube may be terminated at a rational position in the column to minimize the material cost while maintaining the seismic behavior of this composite column. Four SBC specimens were tested under combined constant axial load and cyclic reversed lateral loads. The unique variable in the test matrix was the core steel tube embedment length, which ranged from 1/3 to 3/3 of the column effective height. It is observed that SBCs showed two distinctly different failure patterns, namely brittle shear failure and ductile flexural failure. Tests results indicate that the hysteretic responses of SBCs were susceptible to the core steel tube embedment length. With the increase of this structural parameter, the lateral strength of SBC was progressively improved; the deformability and ductility, however, exhibited a tendency of first increase and then decrease. It is also found that in addition to maintained the rate of stiffness degradation and cumulative energy dissipation basically unchanged, both the ductility and deformability of SBC were significantly improved when the core steel tube was terminated at the mid-height of the column, and these were the most unexpected benefits accompanied with material cost reduction.

A study on the Properties for Structural Behavior of High-Performance Concrete Filled Square Steel Tube Columns -The Behavior Properties by Loading Conditions- (고성능 콘크리트를 충전한 각형강관 기둥의 구조적 거동 특성에 관한 연구 -재하조건별 거동특성-)

  • Park, Jung Min;Lee, Sung Jo;Kim, Wha Jung
    • Journal of Korean Society of Steel Construction
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    • v.10 no.2
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    • pp.177-186
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    • 1998
  • The concrete filled steel tubular column have to superior in compressive load carrying capacity, compared with same section typed hollow steel tube column, and have many excellent structural properties, such as stiffness improvement by filled concrete, improvement of ductility by reinforced effect of local buckling, and the like. However, it has not clear the effect of interaction between steel tube and filled concrete, stress portion ratio and fracture mechanism of concrete. This study investigated to structural properties for high strength concrete filled steel tube column by loading conditions through a series of experiments. Especially, this study investigated the properties of structural behaviors for concrete filled steel tube column stress ratio by loading conditions and failure mechanism of filled concrete.

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Connections between RC beam and square tubed-RC column under axial compression: Experiments

  • Zhou, Xu-Hong;Li, Bin-Yang;Gan, Dan;Liu, Jie-Peng;Chen, Y. Frank
    • Steel and Composite Structures
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    • v.23 no.4
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    • pp.453-464
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    • 2017
  • The square tubed-reinforced concrete (TRC) column is a kind of special concrete-filled steel tube (CFST) columns, in which the outer thin-walled steel tube does not pass through the beam-column joint, so that the longitudinal steel reinforcing bars in the RC beam are continuous through the connection zone. However, there is a possible decrease of the axial bearing capacity at the TRC column to RC beam connection due to the discontinuity of the column tube, which is a concern to engineers. 24 connections and 7 square TRC columns were tested under axial compression. The primary parameters considered in the tests are: (1) connection location (corner, exterior and interior); (2) dimensions of RC beam cross section; (3) RC beam type (with or without horizontal haunches); (4) tube type (with or without stiffening ribs). The test results show that all specimens have relatively high load-carrying capacity and satisfactory ductility. With a proper design, the connections exhibit higher axial resistance and better ductility performance than the TRC column. The feasibility of this type of connections is verified.

The Shear Lag Phenomenon in Bundled Tube Structure According to the Arrangement of Structural Members (부재배치에 따른 묶음튜브 구조의 전단지연현상)

  • Kim, Young-Chan;Kim, Hyun
    • Journal of the Korean Society of Safety
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    • v.21 no.3
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    • pp.81-86
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    • 2006
  • The purpose of this study is to examine the effect of column spacing and beam size on the lateral displacement and shear lag phenomenon in bundled tube system. According to the parametric study in which the spacing of columns, the size of columns and girders in bundled tube were selected as a parameter, it is the most efficient to increase the size of the interior columns with the largest reduction of lateral drift if the steel tonnage of a frame can be increased. It was noticed that the shear lag was affected more by the exterior stiffness factor and ratio than by the interior ones when column spacing was changed, and when the size of column was changed, the reverse phenomenon was happened. And The change of column spacing affected shear lag, lateral drift, and tonnage more than that of column size or girder size.

A Study on the Behaviors of Column-to-Footing Connections for Concrete Filled Tube(CFT) System (콘크리트 충전 각형강관 주각부의 내력 및 변형에 관한 연구)

  • Kim, Cheol-Hwan;Kim, Seong-Eun
    • Journal of Korean Society of Steel Construction
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    • v.22 no.3
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    • pp.253-260
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    • 2010
  • The purpose of this paper is to investigate the behavior of concrete-filled tube columns for footing connections. Eight specimens were tested to investigate such structural behavior according to the column base type. The specimens consisted of concrete-filled steel tube columns (or bare steel tube columns), reinforced concrete footings, and base plates (or stud connectors). The specimens were subjected to lateral cyclic load. The cyclic load was applied according to a predetermined strength sequence. The results of the experiment indicated that the flexural strength of the stud-connector- type column base is higher than that of the base-plate-type column base. The structural behavior of the concrete-filled tube column base was similar to that of the bare steel column base.