• 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.

• Journal of Korean Society of Steel Construction
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• v.13 no.1
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• pp.1-8
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• 2001

The purpose of this study is to examine the utility of concretefilled steel tubular column to H-beam connections with tubular stiffener. As a preliminary step. a tensile experiment was undertaken to scrutinize characteristics of the structural behavior that take place between beam flanges and column with tubular stiffener. A total of 4 types of experimental settings were developed as tabular stiffeners are made up 9, 18, and 27 mm of thickness and 50 and 80 mm of height respetively Along with the overall load subsequently the degree of displacement and strain were recorded. Based on the yield line theory results of this of this study were evaluated and further critically reviewed the applicability of the strength formula. This study found that collapse mechanism was emerged on the beam flange as reinforcing tabular stiffeners Complementary studies of this sort, including numerical analyses should be undertaken in order to develope specific design critera.

• Journal of Korean Society of Steel Construction
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• v.11 no.3 s.40
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• pp.311-318
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• 1999

Concrete filled tubular(CFT) members have many structural and constructional advantages. The prefabrication of CFT members can be thought an idea for the good qualify control of concrete. The objective of this study is to suggest the construction method of prefab CFT beam-columns. Tests are performed to understand their structural behaviors. The opening space between prefab CFT members and the size of tubular members are the parameters of this study. The results of this study will be based on the suggestion of prefab CFT.

• Journal of Korean Society of Steel Construction
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• v.9 no.3 s.32
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• pp.391-400
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• 1997

The objective of this paper is to suggest formula of Concrete Filled Tube Beam-Column members maximum strength by using of numerical analysis and tests. The numerical analysis results are compared with test results for evaluating numerical analysis method. The formula of Limit State Design of Architectural Institute of KOREA is used for basic form of suggestion formula. In order to suggest formula, two methods are used. One is to use the coefficient, and the other is to use the amplified factor of material strength. The formula by two methods are compared with numerical analysis results.

• Journal of Korean Association for Spatial Structures
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• v.6 no.1 s.19
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• pp.55-63
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• 2006

Concrete-filled steel columns consist of circular, square or rectangular hollow sections filled concrete. Much research has studied for the behavior of concrete-filled steel structures. The advantages from structural point of view are the triaxial confinement of the concrete within the section, and the fire resistance of the column which largely depends on the residual capacity of the concrete core. The axial capacity of a concrete-filled rectangular or circular section is enhanced by the confining effect of the steel section on the concrete which depends in the magnitude on the shape of the section and the length of the column. Buckling tends to reduce the benefit of confinement on the squash load as the column slenderness increases. In circular sections it is possible to develop the cylinder strength of the concrete. When compare with reinforced concrete columns, the concrete-filled composite column possesses much better strength and ductility in shear and generally in flexure also. Many researches are being conducted about concrete filled steel column to get these advantages in building design. In this paper it is provided to the basic experimental study of compression behavior of the circular and rectangular tubular steel pipe filled with concrete.

• Journal of Korean Society of Steel Construction
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• v.14 no.5 s.60
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• pp.567-576
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• 2002

Maximum-strength concrete-ailed 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 under uniaxial eccentric load. Likewise, the behavior and maximum strength of columns could be predicted using the analysis.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.1
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• pp.95-102
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• 2011

The CFT columns used in thin-walled steel tubes can be more economical, because it was expected the increase of strength by restriction for the local buckling of steel tubes. The purpose of this paper is to review feasibility of existing design formula and verify the applicability limit of width-to-thickness ratio for increasing the strength of rectangular CFT columns. As the main parameters of experiments, width-to-thickness ratios of steel tube, height of rectangular concrete columns, and concrete filled or not. The strength of concrete are selected to 90MPa. From the test results, the confinement effect of steel tube on the compressive strength of infilled concrete is remarkably appeared in the thin-walled rectangular steel tube columns infilled wih high strength concrete. By the non-linear analysis, the axial strength from experiment result was given higher than analysis result for all CFT stub columns.

• Journal of Korean Society of Steel Construction
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• v.9 no.2 s.31
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• pp.205-220
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• 1997

The objective of this study is to investigate the structural behavior of concrete-filled steel tubular column-H beam connections with exterior stiffeners. As a preliminary test, simple tensile test on the column to H-beam flange connections stiffened were conducted The paramaters of tensile test are the thickness(T=9, 12, 15m) and the width(W=50, 75, 100, 150mm) of exterior stiffeners. The simple tensile test were conducted to 7 kinds of specimens. Estimating the load, displacement, and strain from each kind, results of simple tensile test were compared with results of second test. On the basis of simple tensile test, test on the column to H-km connections stiffened with the sames under monotonic and cyclic load were conducted. Specimens of 5 for the second experiment were made. In analysis, comparing each strengthes and stiffnesses we estimated deformation capacity. Comparing and estimating each yielding strength ratios and maxium-strength ratios on the basis of yield line theory, new strength formula of beam-to-column connections was suggested.

• Journal of Korean Society of Steel Construction
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• v.9 no.3 s.32
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• pp.377-390
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• 1997

The objective of this study is to investigate the structural behavior of concrete-filled steel tubular column to H-beam connections with reinforced bar. As a preliminary test, simple tensile test on the column to H-beam connections stiffened were conducted. The parameters of tensile test are the diameters of each rebars. The simple tensile test were conducted to 5 kinds of specimens. Estimating the load. displacement and strain for specimens, the result of tensile test were compared with the results of main test. On the basis of simple tensile test, tests are conducted to montonic and cyclic loading column to H-beam connections with the same diameters of rebars. Specimens of 5 are made for monotonic and cyclic loading test. In analysis, estimating the yielding strength and maximum strength of specimens on the basis of yield line theory, strength formula of beam-to column connections with concrete-filled steel tubular column was suggested.

• Journal of Korean Society of Steel Construction
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• v.10 no.2 s.35
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• pp.161-175
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• 1998

The objective of this study is to investigate the structural behavior of Concrete-Filled Steel Tubular Column-H Beam connections with plate stiffeners. The first, we made experiment on the Column to H-beam flange connections stiffened with simple tensile loading. The paramaters of tensile experiment are the area of each plates. The simple tensile experiment is conducted to 5 kinds of specimens. Eestimating the load, displacement, and strain from each kind, we compared them with results of second experiment. The second, we made experiment on the Column to H-beam connections stiffened with the sames under monotonic and cyclic load. we made specimens of 5 for the second experiment. In analysis, comparing each strengthes and stiffnesses we estimated deformation capacity. Comparing and estimating each yielding strength ratios and maxium-strength ratios on the basis of Yield line theory, we suggested new Strength Formula of Beam-to-Column Connections.