• Journal of the Computational Structural Engineering Institute of Korea
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• v.18 no.2
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• pp.169-179
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• 2005

An improved method for evaluating effective buckling lengths of beam-column members in plane frames is newly proposed based on system inelastic buckling analysis. To this end, the tangent stiffness matrix of be am-column elements is first calculated using stability functions and then the inelastic buckling analysis method is presented. The scheme for determining effective length of individual members is also addressed. Design examples and numerical results ?uc presented to show the validity of the proposed method.

• Journal of Korean Society of Steel Construction
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• v.14 no.1
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• pp.121-130
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• 2002

This paper presents the tensile behavior of a Concrete-Filled Square Steel Tubular (CFT) column to H-beam welded connections. These connections were externally reinforced with T-shaped stiffeners at the junction of CFT column and beam. The tensile loading tests of eighteen tee-joint connections and finite element analysis using ANSYS were carried out. The main parameters of tests are as follows: 1) the thickness of Square Steel Tubular Column : 6 mm, 9 mm, 2) the strength ratios of tensile strength of horizontal stiffeners to tensile strength of beam flange : 70 %, 100 %, 150 %, 3) the strength ratios of shear strength of vertical stiffeners to tensile strength of beam flange : 80 %, 115 %, 160 %. The results of the tests demonstrate that overall behavior and failure modes of all the specimens are governed mainly by the horizontal stiffeners rather than the vertical stiffeners, and the vertical stiffener played only a role in transferring load introduced from beam to column.

• Journal of Korean Society of Steel Construction
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• v.9 no.4 s.33
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• pp.523-533
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• 1997

Current limit state design method for encased composite columns contains irrational and uncertain design equations in defining section and material properties of composite members. Through investigating previous research used in formulating the design equation, this paper explores the irrationality and uncertainty such as 1) transformation of yield stress and elastic modulus for composite section, 2) an equation influencing buckling strength in terms of area rather than moment of inertia, and 3) selection of larger radius of gyration between steel and concrete sections. Improving the design equations this paper proposes two design methods which can be directly used in practical design.

• Journal of Korean Society of Steel Construction
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• v.20 no.1
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• pp.195-203
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• 2008

This paper aims to evaluate the yield stress of SM570TMC concrete-filed H-shape steel columns subjected to axial force. These columns were evaluated and compared using quasi-static tests. The displacements and the axial loads column specimens were measured during the tests, and test results showed that the yield stress of concrete-filed H-shape steel columns subjected to axial load could be predicted using the previously proposed yield stress of steel columns.

• Journal of Korean Society of Steel Construction
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• v.25 no.2
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• pp.187-196
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• 2013

CFT structures require a diaphragm to prevent buckling of steel at connections. An outer diaphragm has better concrete filling than a through diaphragm due to a large bore, but due to the larger size than the through diaphragm, it has poorer constructability and cooperation with building equipment. The building structure has a floor slab that was unified with the upper diaphragm, so the outer diaphragm was placed at the upper bound. Moreover, the through diaphragmwas placed at the lower connection to avoid obstruction of the building equipment. The CFT structure with the improved concrete filling showed the same structural behavior as the CFT structure with the use of the same type of diaphragms at the upper and lower connections.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.2
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• pp.143-152
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• 2006

High performance concrete(HPC) has been widely used in high-rise building. The HPC has several benefits including high strength, high fluidity and high durability. However, spalling is susceptible to occur in HPC and HPC also tends to be deteriorated in the side of fire resistance performance at fire. This paper investigated the spalling prevention of high performance RC column. Control concrete showed severe failure and a case of concrete with fire enduring spraying material exhibited more severe spalling failure than even control concrete. In addition, concrete with fire enduring paint reported the most favorable spalling resistance effect for preventing spall, compared with other concrete covered with finishing materials, such as fire enduring spraying material, gypsum board, marble board and fire enduring PC board. Meanwhile, concrete adding 0.1% of PP fiber demonstrated spalling resistance performance after 3hours load bearing test.

• Journal of the Korea Furniture Society
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• v.21 no.6
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• pp.469-478
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• 2010

Fire resistance of new hybrid timber framed wall systems was evaluated in this study. These wall systems are composed of two major structural parts. One part is a heavy timber frame part designed to take charge of whole vertical load using heavy timber post and beam, and the other is an infill wall structure, designed to take charge of whole horizontal load and to provide an established level of fire resistance. A basic concept of this hybrid wall is adopted from a typical furniture structure with frame. A timber post and beam frame is constructed with Japanese Larch solid timber post(180mm by 180mm) and beam(180mm by 240mm). As infill wall systems, two types of walls are applied. One is a typical light timber framed wall with solid blocking and another is a structural insulated panel wall, in which polystyrene insulation is filled between two structural panels to make single structure. For all tested walls, two layers of 12.5mm thick type-X gypsum boards are used on fire exposed side. Prior to tests for hybrid walls, only infill walls are tested without heavy timber frame. All fire resistance tests are carried out in accordance with KS F 2257, and temperatures on several points within wall structure and unexposed wall surface are measured during fire tests. It is considered that the reinforcement of heavy timber frame is significantly efficient for improving the fire resistance of timber framed walls.

• Journal of the Korea Concrete Institute
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• v.18 no.3 s.93
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• pp.405-414
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• 2006

In the present study, a numerical analysis was performed for interior connections of continuous flat plate to analyze the effect of design parameters such as column section shape, gravity load and slab span on the behavioral characteristics of the connections. For the purpose, a computer program for nonlinear FE analysis was developed, and the validity was verified. Through the parametric study, the variations of shear stress distribution around the connection were investigated. According to the result of numerical analysis, as the length of the cross section of column in the direction of lateral load increases and gravity load increases, the effective area and the maximum shear strength providing the torsional resistance decrease considerably. And as the slab span loaded with relatively large gravity load increases, the negative moment around the connection increases and therefore the strength of connection against unbalanced moment decreases. By considering the effect of design parameters on the strength of the connections, the effective shear strength to calculate the torsional moment capacity of connection was proposed and the effectiveness of the proposed shear strength was verified.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.107-108
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• 2009

This is an experimental study on using the Honeycomb System show you the method of increasing ability of ductility and shear strength seismic performance to reinforced concrete column and masonry waist-high wall.

• Journal of Korean Society of Steel Construction
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• v.18 no.6
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• pp.805-813
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• 2006

The objective of this study is to ascertain the applicability of T-stub connection for rigid connections. Tests and analysis are focused on the initial stiffness and their results are compared with the case of general rigid connections. Influential factors are investigated from the analysis results.