• Journal of Korean Society of Steel Construction
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• v.24 no.6
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• pp.637-645
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• 2012

The composite action in truss beam is generally achieved by providing shear connectors between the steel top chord of the truss and the concrete slab. The composite sections have greater stiffness than the sum of the individual stinesses of the slab and truss. Therefore, steel trusses that act compositely with concrete slabs can carry larger load and are stiffer and less prone to transient vibration. The crack pattern and deflection of the beam of the composte truss were investigated by using of 600MPa class steel in this study. The test results were compared with the results for the noncomposite trusses. Test results were also compared with the results of composite trusses by using of 400MPa class steel. It was ascertained that the case of high strength steel is more efficient compared with the case of SS400 steel for T-shaped steel.

• Journal of Korean Society of Steel Construction
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• v.22 no.6
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• pp.563-572
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• 2010

This study evaluates the load-carrying capacity of a thermal prestressed steel beam with an eccentric bracket. The steel beam that is proposed in this study has an eccentrically installed cover plate through application of the eccentric bracket. The eccentric bracket helps the steel beam achieve greater sectional stiffness and more efficiently induces prestress. A material non-linear characteristic applied finite element analysis was also conducted to check the validity of the experiments. The results of this study showed that the structural stiffness, yield load, and ultimate strength of the TPSM-applied steel beam with the eccentric bracket increased due to the eccentricity of the cover plate.

• Journal of Korean Society of Steel Construction
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• v.22 no.6
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• pp.543-551
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• 2010

The end-reinforced composite-beam (eco-girder) system was developed that has characteristics of the existing composite beams such as reduced floor height and increased strength. With it, less use of steel is expected. In the eco-girder system, only both ends of the steel-frame beam, which are vulnerable to the ultimate moment, are reinforced with steel plates so that the steel frame beam design will be based on the moment at the beam center. This study used fiber element analysis, which is a simple representation and numerical integration of the principles of the detailed Finite Element Method(FEM), to predict the hysteretic behavior of reinforced composite beams under cyclic loading. The validity of the numerical method was verified by comparing the results of this study with those of previous studies. In addition, the hysteretic behavior of the eco-girder was compared with that of the existing composite beams.

• Journal of Korean Society of Steel Construction
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• v.25 no.5
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• pp.463-474
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• 2013

Many experimental and numerical researches for thin-walled carbon steel and austenitic stainless steel single shear bolted connections have been conducted and the modified design equations of ultimate strength were proposed. In this study, the tests of double shear bolted connections with bolt arrangements ($2{\times}1$, $2{\times}2$) and end distance parallel to the loading direction as main variables were performed. Specimens were planed with a constant dimension of edge distance perpendicular to the loading direction, bolt diameter, pitch and gauge like single shear bolted connections. The test results such as ultimate strength and fracture mode were compared with those of current design standards. Furthermore, modified block shear equations for double shear bolted connections were suggested.

• Journal of Korean Society of Steel Construction
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• v.25 no.6
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• pp.659-669
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• 2013

The purpose of this study is to investigate the ultimate strength and curling influence using finite element analysis based on the previous test results of ferritic stainless steel bolted connections. Results obtained from finite element analysis (FEA) were compared with those of test results and the validity of numerical modeling was verified. The conditions of curing occurrence for edge/end distance were investigated and ultimate strength reduction ratio caused by curling was estimated quantitatively. Moreover, the ultimate behaviors such as fracture mode and ultimate strength by FEA were compared with those predicted by current design specifications such as AISC, KBC2009, AIJ and AISI.

• Journal of Korean Society of Steel Construction
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• v.25 no.5
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• pp.543-553
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• 2013

As the deep deck plate has the shape of open cross section, It can cause structural problems such as bending torsions due to instability of the section. There are a number of fasteners types which are frequently used on light gage steel diaphragms such as bolts, rivets, welds, and screws. In this study, the structural capacity of the self drilling screw connection between the deep deck and the reinforced cap plate was evaluated by experimental variables such as the arrangement method, numbers of screw, pitch of screw, and head plate thickness.

• Journal of Korean Society of Steel Construction
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• v.29 no.2
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• pp.99-110
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• 2017

This paper presents the study of the bending behavior of mooring chain links for keeping the position of the offshore floating structures. In general, chain links have been thought as the axial members due to the fundamental boundary condition. But, the flexural stiffness can be induced to the contact surface between chain links when friction occurs at the surface of the chain links due to high tensile force. Especially, the mooring chains for offshore floating platforms are highly tensioned. If the floater suffers rotational motion and the mooring chain links are highly tensioned, the rotation between contact links, induced by the floater rotation, generates the bending moment and relevant stresses due to the unexpected bending stiffness. In 2005, the mooring chain links for the Girassol Buoy Platform were failed after just 5 months after facility installation, and the accident investigation research concluded the chain failure was mainly caused by the fatigue due to the unexpected bending stress fluctuation. This study investigates the pattern of the induced bending stiffness and stresses of the highly tensioned chain links by nonlinear finite element analysis.

• Journal of Korean Society of Steel Construction
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• v.12 no.6
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• pp.701-713
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• 2000

In this study, the 4-point bending test been performed in order to estimate effect of grinding on fatigue characteristics quantitatively for as-welded specimen, grinding specimen & TIG-dressing specimen for non load-carrying fillet welded joints subjected to pure bending. As a result of fatigue tests, fatigue strength at $2{\times}106$cycles of grinding specimen and TIG-dressing specimen has been increased compared with as-welded specimen and satisfied the grade of fatigue strength prescribed in specifications of domestics and AASHTO & JSSC. As a result of beachmark test, fatigue cracks on all specimens have occurred at several points where stress

• Journal of Korean Society of Steel Construction
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• v.12 no.6
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• pp.749-758
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• 2000

This study presents a governing equations of bending behavior of sandwich plates with thick metal, polymer composite facings. Based on zig-zag models for through thickness deformations, the transverse shear deformation of composite facings is included. All edges of plate are assumed to be simply supported. Results of the bending analysis under lateral loads are presented for the influence of various lay up sequences of antisymmetric angle-ply laminated facings. The accuracy of the approach is ascertained by comparing solutions from the sandwich plates theory with composite facings to the laminated plates theory. Since the present analysis considers the bending stiffness of the core and also the transverse shear deformations of the laminated facings, the proposed method showed higher than that calculated according to the general laminated plates theory. The information presented might be useful to design sandwich plates structure with metal, polymer matrix composite facings.

• Journal of Korean Society of Steel Construction
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• v.12 no.6
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• pp.759-767
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• 2000

In this study, the time dependent internal stress changes of a Concrete Filled Steel Tube(CFT) column during a fire test were quantitatively analyzed. The strain ratio of a CFT column on the different loads was measured by tensile strength tests in terms of yield strength, tensile strength average extensibility and elasticity modulus. To understand the internal material properties change of concrete in CFT column damaged due to a fire, the compressive strength and elastic modulus tests were measured on a core sample from the center of the steel tube after the fire test. The elastic modulus test measured the strain from the stress. To determine the fire temperature of the test material, a differential thermal analysis was done. From the tested result, the gained data were conducted and an analysis method was suggested. The purpose of this work is to suggest a basic data for structure regulation enactments of the internal fire design of CFT.