• Journal of Korean Society of Steel Construction
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• v.19 no.1
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• pp.117-127
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• 2007

In this study, we evaluate the strength of steel box beam-to-column connections subjected to axial loads in steel frame piers. The T-connection strength was reduced due to the column axial force in the two-story pier structure. To examine this phenomenon, non-linear FEM analysis was carried out and the analytical procedure was verified by comparing it with experimental results. To clarify the effect of the axial force and major design parameters in connection with strength, influence of panel zone width-thickness ratio, sectional area, and axial force was investigated using FEM analysis. Also, the theoretical strength equations were suggested by stress distribution of panel zone. The strength of the T-connection was compared with one of the one-story pier structure connections. As a result, the strength evaluation equations are proposed in consideration of the panel zone width-thickness ratio and sectional area ratio for the T-connections.

• Journal of Korean Society of Steel Construction
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• v.19 no.1
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• pp.1-13
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• 2007

As girders and towers in cable-stayed bridges are subject to bending moments as well as axial forces, the conventional load rating equation, which considers only the single force effect, cannot be used to evaluate the rating factors of cable-stayed bridges. The load rating equation for components in cable-stayed bridges is not currently established yet. In this paper, we propose load rating equations for girders and towers in cable-stayed bridges using the interaction equations for beam-column members. Moving load analyses were performed for the cases of a maximum axial compressive force, maximum positive moment and maximum negative moment for each component in cable-stayed bridges and detailed procedures to apply proposed equations were presented. The Dolsan Grand Bridge was used to verify the validity of proposed equations. The conventional load rating equation overestimates rating factors of girders and towers in the Dolsan Grand Bridge, whereas proposed equations properly reflect the axial-flexural interaction behaviour of girders and towers in cable-stayed bridges.

• Journal of Korean Society of Steel Construction
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• v.20 no.6
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• pp.793-805
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• 2008

Recently, steel modular systems are developed and have been applied to the projects requiring fast construction such as military barracks and vertical expansion of school buildings. The existing modular system with standard module of ${6m\times3m}$ has a problem that many columns are duplicated in the module connection and the wall thickness increases. In this study, $12m{\times}3m$ module is proposed to solve this problem. Various types of beam-middle column connection which are essential for realizing the $12m{\times}3m$ module are proposed and their maximum load capacity and failure mode are analytically and experimentally evaluated. The comparison between analytical and experimental results shows that the maximum axial load and failure mode can be accurately estimated by finite element analysis. Some connection types which have higher failure load than the design load of the column, can be used as the beam-middle column connection detail of the $12m{\times}3m$ module.

• Journal of Korean Society of Steel Construction
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• v.20 no.6
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• pp.691-700
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• 2008

Contemporary architectural structures have diverse and complex forms. Such structural variety demands requisite performance from the connections in the steel structure so that the latter could resist a horizontal force, such as an earthquake. The connections are the all-important components that create the discontinuous form and that support stress concentration, determining the stiffness and toughness of the entire steel frame. In this study, a real-scale column-to-beam connection was constructed in the 600MPa-grade high-strength and high-performance steel, to test its behavior. Its material and welding characteristics were examined in this study, and its structural performance was analyzed by conducting seismic-resistance tests on the full-scale, cross-shaped column-to-beam welded connections with non-scallop, ordinary-scallop, and reinforced-scallop details. The weld ability of the high-strength, high-performance steel was also evaluated, and data regarding the seismic design for practical application were provided.

• Journal of Korean Society of Steel Construction
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• v.23 no.6
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• pp.659-667
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• 2011

Wind tunnels tests have been evaluating wind load estimation by discussing the most important design elements in very tall buildings. Such tests have some uncertainties, however, with respect to the data of the reduced model and the calculated empirical values. In contrast, CFD analysis can simulate the actual scale and shorten the time of simulation. Nevertheless, the utilization of CFD analysis is negligible because of its low reliability. In this paper, the reliability of CFD analysis will be proven by comparing the results of a wind tunnel test and CFD analysis for the prototype models shown in previous studies. The effect of the turbulence intensity on the reliability is also presented.

• Journal of Korean Society of Steel Construction
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• v.21 no.3
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• pp.321-330
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• 2009

This paper presents numerical analysis results for the lateral-torsional buckling (LTB) strength of steel I-girder bridges. Current Korean and AASHTO design specifications for LTB consider the buckling strength of a single girder with both its ends constrained. The I-girder bridges are composed of more than one girder, and the girders are interconnected with intermediate cross-beams or cross-frames. Therefore, it should be required to evaluate the effects of cross-beam stiffness and the interactionof girders on LTB strength. It is also necessary to consider the effects of transverse web stiffeners on LTB strength. By considering these parameters, a series of four-girder systemswere numerically modeled using 3D shell elements to estimate the LTB strength while considering initial imperfections and residual stresses.

• Journal of Korean Society of Steel Construction
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• v.21 no.3
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• pp.301-310
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• 2009

Steel has been widely used as a material in temporary structures. Corrosion attack often reduces the long-term durability of temporary steel members that are not protected from corrosion. In designing temporary steel structures, it is difficult to evaluate their long-term durability, since the thickness loss of steel members is not clear. In this study, laboratory and field exposure corrosion tests were performed on structural steel plate specimens, and the loss of thickness of specimens that were exposed to a subway construction site for 11 months and of specimens that were exposed to environments with controlled humidity and calcium chloride for six months were measured. Finally, a thickness loss equation was formulated based on the environmental conditions and the testing periods.

• Journal of Korean Society of Steel Construction
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• v.16 no.5 s.72
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• pp.641-652
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• 2004

The strong beam-to-column axis connections in steel structures have been studied for a long time to develop the strength and resistance of the connections. There have been very few studies, however, related to weak axis connections. Domestically, the bracket-type connection is commonly used in weak axis connections to elevate the efficiency of the constructions when the steel structures are constructed. The bracket-type connection detail has been applied moderately to weak axis connections. Therefore, the bracket-type connection in weak axis connections might be brittle and over-designed. The results of this study showed that the welding on the web of the column and the beam was unnecessary. In addition, this study confirmed that the new weak axis connection proposed in this study was superior to the previous connection in terms of strength and ductility.

• Journal of Korean Society of Steel Construction
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• v.16 no.5 s.72
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• pp.599-607
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• 2004

As buildings become more high-rise and lightweight in recent years, steel has been utilized more frequently. Based on the American AISC standard, all axial loads could be carried through a bearing load in a column splice, but according to Korean codes, the bearing load has constrained the stress that could be carried by only 25% of all axial loads. Thus, new column splice methods that use metal touch have been examined. In this study, the stress path mechanism, as an intermediation parameter in the gap's magnitude, must be determined. Similarly, the behavioral aspect of the metal touch connection must be sought after comparing and analyzing the results of the test.

• Journal of Korean Society of Steel Construction
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• v.16 no.5 s.72
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• pp.671-682
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• 2004

This study investigated the effects of a shear slip on the deflection of steel-concretecomposite beams with partial shear interaction. Under the guidance of various current design codes, this deflection was related to the strength of shear connectors in the composite beams. In this paper, a shear connector stiffness based on exact solutions, regardless of loading conditions, was developed. The equivalent rigidity of composite beams that considered three different loading types was first derived, based on equilibrium and curvature compatibility, from which a general formula accounting for slips was developed. To validate this approach, the predicted maximum deflection under the proposed method was compared against currently used equations to calculate beam effective stiffness (AISC)Nie's equations, which have recently been proposed. For typical beams that were used in practice, shear slips might result in stiffness reduction of up to 18% for short-span beams. For full composite sections, the effective section modulus with the AISC specifications was larger than that of the present study, which meant that the specifications were not conservative. For partial composite sections, the AISC predictions were more conservative than those in the present study.