• Title/Summary/Keyword: concrete filled tube (CFT) columns

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Tension test considering the shape change of CFT Column-to-Beam Interior Diaphragm (CFT 기둥-보 내다이아프램의 형상변화를 고려한 인장실험)

  • Kwak, Sung-Shin;Choi, Byong-Jeong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.2
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    • pp.67-75
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    • 2019
  • The diaphragm used for CFT columns has a small amount of steel to be used, but has a disadvantage that welding is difficult and openings are required because the steel tube and four sides must be welded. The improved diaphragm to be examined in this study was cut into four corners by cutting the center hole for concrete filling. In the improved diaphragm, the width of the center hole is the same as that of the previous diaphragm, but the width of the diaphragm contacting the steel tube is reduced, thereby reducing the welding length by about 70% compared to the previous diaphragm. The in-plane strain of each specimen was analyzed when the same load was applied to the interior diaphragm through a simple tensile test. Using the general FEM program(ANSYS 19.2), the analysis was performed under the same conditions as the actual simple tensile test, and the load transfer between the improved diaphragm and the previous diaphragm was compared. When the width of the diaphragm is equal to or smaller than the flange width, stress is concentrated from the end of the diaphragm, and when the flange width is larger, stress is concentrated at the center.

Cyclic Loading Test for Beam-to-Column Connections of Concrete Encased CFT Column (콘크리트피복충전 각형강관 기둥-보 접합부의 주기하중 실험)

  • Park, Hong Gun;Lee, Ho Jun;Park, Sung Soon;Kim, Sung Bae
    • Journal of Korean Society of Steel Construction
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    • v.26 no.1
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    • pp.55-68
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    • 2014
  • In this study, the beam-to column connections of concrete-encased-and-filled steel tube columns were tested under cyclic loading. Two specimens using steel beams and two specimens using precast concrete beams were tested. The dimension of the column cross section was $670mm{\pm}670mm$. The beam depths were 488mm and 588mm for the steel beams and 700mm for the precast concrete beams. The longitudinal bar ratios of the precast concrete beams were 1.1% and 1.5%. For the connections to the steel beams, continuity plates were used in the tube columns. For the connections to the PC beams, couplers were used for beam re-bar connections. The test results showed that except for a specimen, deformation capacities of the specimens were greater than 4% rotation angle, which is the requirement for the Special Moment Frame. Particularly, specimens using precast concrete beam showed excellent performances in the strength, deformation, and energy dissipation.