• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.5 no.2
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• pp.17-23
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• 1999

Top-to-bottom compression strength of corrugated fiberboard boxes is partly dependent on the load-carrying ability of the central panel areas. The ability of these central areas to resist bending under load will increase the stacking strength of the box. The difference of box compression strengths, among boxes which are made with identical dimensions and fabricated with same components but different flute sizes, is primarily due to difference of the flexural stiffness of the box panels. Top-to-bottom compression strength of a box is accurately predicted by flexural stiffness measurements and the edge crush test of the combined boards. This study was rallied out to analyze the flexural stiffness, maximum bending force and maximum deflection for various corrugated fiber-boards by experimental investigation. There were significant differences between the machine direction (MD) and the cross-machine direction (CD) of corrugated fiberboards tested. It was about 50% in SW and DW, and $62%{\sim}74%$ in dual-medium corrugated fiberboards(e.g. DM, DMA and DMB), respectively. There were no significant differences of maximum deflection in machine direction among the tested fiberboards but, in cross direction, DM showed the highest value and followed by SW, DMA, DMB and DW in order. For the corrugated fiberboards tested, flexural stiffness in machine direction is about $29%{\sim}48%$ larger than cross direction, and difference of flexural stiffness between the two direction is the lowest in DMA and DMB.

• Journal of Korean Society of Steel Construction
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• v.15 no.5 s.66
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• pp.591-601
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• 2003

Because of their high out-of-plane and in-planes strength, trapezoidally corrugated plates have been increasingly used in buildings and bridges. If corrugated plates are used as the web of plate girders or prestressed concrete box girders, the flanges take most of the bending stress. On the other hand, the corrugated plate web supports shear stress due to the accordion effect. The corrugated plate web could fail by three different buckling modes: global, local, or interactive shear buckling. To determine the effects of geometric parameters on the buckling capacity of the corrugated plates, a parametric study was performed using finite dement method. The analysis results showed that the buckling capacity and modes depend on individual parameters as well as combinations of parameters.

• Journal of Korean Society of Steel Construction
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• v.23 no.6
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• pp.679-690
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• 2011

Since the elastic buckling problem of the plate has been studied both experimentally and theoretically, the buckling loads with various boundary conditions and loads can be easily determined. Currently, flange and web design specifications are based on the buckling stress and the post-buckling strength and include a safety-factor. Therefore, this study extended suchresearch to the linear buckling theory with ideal conditions and to the ultimate state with post-buckling. The current specifications are based on elastic buckling stress; and therefore, further research on the ultimate behavior of the plate is required. The ultimate strength design concept, which allows finite deflection, is used in this studyto maximize the post-buckling strength in a steel box. An empirical equation, which provides the ultimate strength of the steel box due to the change in the slenderness and optimum rigidity, are suggested based on the experiment results. Moreover, the appropriateness of the current design specifications was analyzed and discussed.

• Journal of Korean Society of Steel Construction
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• v.16 no.5 s.72
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• pp.505-517
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• 2004

This paper presented equations on the stress evaluation of steel frame pier connections that were composed of a box beam and a circular column. The existing equations, which transformed the circular column into an equivalent box column had some problems; they underestimated a shear lag stress as the joint angle decreased, and overestimated a shear stress as the joint angel increased. Therefore, FE analyses were performed with various parameters, such as joint angle(${\alpha}$), span length-width ratio(L/B), and circular column-to-box beam stiffness ratio(${\alpha}$), and new equations on stress evaluation were proposed based on FE analyses. Furthermore, material and geometric nonlinear analyses were performed to estimate ultimate strength and to confirm the validity of the proposed equations.

• Journal of Korean Society of Steel Construction
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• v.21 no.6
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• pp.647-657
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• 2009

This paper studies the behavior of joints in steel-PSC (prestressed concrete) hybrid beams, which is necessary for the application of hybrid beams to spliced girder bridges, and proposes a new type of joint with improved construction convenience and structural behavior. In the proposed joint, perfobond rib shear connectors are attached to the upper and lower plates, which are expanded from the steel girders and located between the steel girder and the PSC girder. The experimental tests were performed on hybrid beams with the suggested joint. The results showed that all the beams had similar ultimate strengths and failure modes, due to the failure of their PSC parts. The composite action of the perfobond ribs was verified by examining the initial stiffness and cracks of the test beams. In addition, the test beams showed a higher degree of ultimate strength than the beams with stud shear connectors in the joints that had been previously studied. Thus, the proposed joint is effective for the steel-PSC hybrid beam.

• Journal of the Korean Geotechnical Society
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• v.18 no.3
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• pp.43-50
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• 2002

This paper describes a simplified numerical procedure for analyzing the response of bridge pier foundations due to riverbed scouring. A computationally efficient algorithm to analyze the behavior of a pile group is proposed by considering soil-pile, pile-cap, and pile-fluid interactions. The complex phenomenon of the pile-soil interaction is modeled by discrete nonlinear soil springs (p-y, t-z and q-z curves). The pile-cap interaction is considered by geometric configuration of the piles in a group and connectivity conditions between piles and the cap. The pile-fluid interaction is incorporated into the procedure by reducing the stiffness of the soil-pile reactions as a result of nonlinearity and degradation of the soil stiffness with river bridge scouring. Through the numerical study, it is shown that the maximum bending moment increases with increasing scour depth. Thus it is desirable to check the stability elf pile groups based on soil-pile and pile-cap interactions by considering scouring depth in the riverbed.

• Journal of the Korean Geotechnical Society
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• v.20 no.2
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• pp.107-113
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• 2004

A new innovative prestressed support (IPS) earth retention system has been developed and introduced. The IPS is a wale system prestressed by steel wires. The IPS consists of wale, wires, and H-beam support. The IPS provides a high flexural stiffness to resist the bending by earth pressures. The IPS earth retention system provides a larger spacing of support, economical benefit, construction easiness, good performance, and safety control. This paper explains basic principles and mechanism of new IPS system and presents a design method of IPS earth retention system. In order to investigate applicability and safety of new IPS system, field tests were performed in a trench excavation. The new IPS system applied in a trench excavation was performed successfully. The measured performances of IPS system were presented and discussed.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.2
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• pp.129-138
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• 2012

This paper deals with geometrical non-linear analyses of the tapered variable-arc-length beam, subjected to the combined load with an end moment and a point load. The beam is supported by a hinged end and a frictionless sliding support so that the axial length of the deformed beam can be increased by its load. Cross sections of the beam whose flexural rigidities are functionally varied with the axial coordinate. The simultaneous differential equations governing the elastica of such beam are derived on the basis of the Bernoulli-Euler beam theory. These differential equations are numerically solved by the iteration technique for obtaining the elastica of the deformed beam. For validating theories developed herein, laboratory scaled experiments are conducted.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.5
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• pp.447-454
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• 2012

Considering that the weight of a hollow slab system is not increased with an incremental increase in its thickness, and that the flexural stiffness of a hollow slab is not significantly lower than that of a general slab, there has been a growing need for hollow slab system, because long span structures are in great demand. In a long span structure, the problem of vibration of floor slabs frequently occurs, and the dynamic characteristics of a hollow slab system are quite different from the conventional floor system. It is required to investigate the safety and the serviceability of hollow slab. Therefore, there exists a necessity for accurate vibration analysis. Hollow slab should be modeled by refined mesh for accurate vibration analysis. For the efficiency of the Eigenvalue Analysis, an equivalent plate slab model when can relatively precisely represent the dynamic behavior of a one-way hollow slab system is used. In conclusion, equivalent plate models relatively precisely presented the dynamic characteristics of one-way hollows.

• Magazine of the Korea Concrete Institute
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• v.9 no.2
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• pp.99-108
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• 1997

Many studies on the second-order analysis of reinforced concrete columns have been dealt for symmetric sections under uniaxial loading. However, actual columns are practically subjected to hiaxial loading. In order to more accurately predict the behavior of concrete columns under biaxial loading. the interaction between bending moments of major and minor axes should be considered. In this paper, a stiffness matrix of columns under biaxial loadings was derived and a numerical method was proposed. Numerical analyses, based on the proposed method. were performed to predict behavior of concrete columns with square and rectangular sections under various loading conditions. The analytical results were compared to those using the moment magnifier method in ACI code. It was found that the ultimate strength of concrete rectangular columns, fhr some cases of' biaxial loading conditions. calculated by the moment magnifier method was larger than the values based on the proposed method and therefore. may be ovet.'stimated.