• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.4A
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• pp.487-495
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• 2008

The behavior of nose-deck system during launch was examined by three dimensionless launching parameters, such as the relative flexural stiffness, the relative nose weight, and the relative nose length. The techniques of optimizing the launching nose were illustrated and equations of relationship between relative nose weight and relative nose length were derived under minimum conditions of the launching negative and positive moment. Equations of maximum positive and negative moment were suggested under the conditions. The optimum design method of the launching nose was proposed in launched continuous girder bridges. It was found that the ideal launching nose was to design that with the relative nose weight of 0.167 and the relative nose length of 0.836 to minimize absolute values of the positive and negative moment during launch.

• Journal of Korean Society of Steel Construction
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• v.9 no.1 s.30
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• pp.149-157
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• 1997

철골 모멘트 접합부를 헌치로서 보강할 경우 내진거동이 크게 증진됨이 최근의 실물대 시험에서 입증되고 있다. 본 연구에서는 헌치로서 보강된 철골 모멘트 접합부가 골조의 탄성 횡변위 거동에 미치는 영향을 해석적으로 평가하는 방안을 제시하였다. 즉 내부의 보-기둥 부분골조를 대상으로 기둥, 보 및 이중패널존에서 기인하는 탄성 횡변위 성분을 해석적으로 유도하였다. 핵심이 되는 내용은 헌치 보강시 생성되는 이중패널존의 전단변형을 고려하는 것이었다. 제시된 방안에 의한 예측치는 3차원 유한요소해석에 의한 결과와 잘 부합하였다. 본 연구에서 수행한 사례연구에 의할 때 헌치의 도입으로 패널존의 강성증대가 가장 현저하여서 패널존의 전단변형에서 기인하는 탄성 횡변위가 50%정도 감소되었다. 본 연구의 결과는 아직 잘 알려지지 않은 헌치 보강에 따른 부차효과(side effects)의 이해에 도움이 될 수 있을 것이다.

• Journal of Korean Society of Steel Construction
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• v.29 no.1
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• pp.1-12
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• 2017

This paper proposes nominal flexural strength considering strain-hardening effect of HSB600 high performance steel for compact composite I-girders in positive bending. Unlike conventional steels, HSB600 undergoes strain-hardening just after yielding without going through yield plateau. However, because the nominal flexural strength specified in domestic and foreign bridge design specifications has been developed for the conventional steel composite girders, the nominal flexural strength does not appropriately consider the strain-hardening of HSB600. Therefore, plastic moment considering a strain-hardening is proposed so as to consider effect of the strain-hardening of HSB600 on flexural strength and then moment-curvature analysis is performed to a wide range of cross-sections. From results of the analysis, a parameter representing the effect of the strain-hardening on the flexural strength of HSB600 composite girders is proposed. Furthermore, by using this parameter, the nominal flexural strength considering the strain-hardening effect for HSB600 composite I-girders in positive bending is proposed and then evaluated by comparing with the current AASHTO LRFD bridge design specifications.

• Journal of the Korea Concrete Institute
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• v.20 no.1
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• pp.23-33
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• 2008

The moment redistribution in continuous reinforced concrete beams is very feasible phenomenon, by which the efficiency and the economy in designing reinforced concrete members can be enhanced. However, to understand the structural behavior by moment redistribution phenomenon, it is desirable to verify its mechanism experimentally considering tension stiffening effect, the relationship of moment redistribution and beam deflection, crack pattern, and effective stiffness. Six reinforced concrete continuous beam specimens were fabricated, and each specimen had a dimension of 250 mm $\times$ 350 mm and 7,000 mm long. The location of de-bonding was taken as the primary test parameter to investigate tension stiffening effect. The moment redistribution ratio of the specimens was different depending on the position of de-bonding, and in particular no moment redistribution was observed when de-bonding exist at both ends, the maximum negative moment region and the maximum positive moment region.

• Journal of the Korea Concrete Institute
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• v.18 no.3 s.93
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• pp.313-320
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• 2006

Prestressed composite girder with concrete infilled steel tubes(PSC-CFT girder) is new type of bridge girder which enhances the resisting capacities due to the double composite action of PSC composite girder and concrete infilled tube. The flexural behaviors of PSC-CFT girder in the positive moment regions are investigated based on the experimental observations recently performed on two of 4.4m long specimens. The mechanical and structural roles and failure mechanism of the composite action are discussed through comparing the test results with those numerically predicted by the three methods of one- and three-dimensional nonlinear finite element analyses, and section analysis method.

• Journal of the Korean Geotechnical Society
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• v.28 no.6
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• pp.5-17
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• 2012

The moment responses of electric pole foundations for a railway were investigated using real-scale load tests. Large overturning moments were applied to two circular rigid piles with a 0.75 m diameter and a 2.5 m embedded depth; the circular rigid piles were installed in an actual railway embankment fill. Two different loading directions-toward the fill slope and toward the track -were applied to evaluate the influence of the fill slope on the moment capacities of the foundations. It was found that the failure of the foundations that were constructed according to Korean railway practices exhibited a sudden overturning pattern without any significant pre-failure displacement. The moment capacity toward the fill slope was less than the moment capacity toward the track by 30%. From the test results, the geometry factor (K), which accounted for the reduction of the moment capacity, due to the fill slope, was 0.7. Moment capacities determined from the load tests were compared with those predicted from three existing design methods, and their applicability was discussed.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1995.10a
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• pp.27-31
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• 1995

• Journal of the Korean Chemical Society
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• v.22 no.5
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• pp.295-303
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• 1978

The dipole moments for octahedral [Co(III)-$O_3N_3$], tetrahedral [M(II)-$O_2N_2$] and square planar [M(II)-$O_2N_2$] types complexes are calculated by the expansion method for spherical harmonics using the valence basis sets for the central metal ion and the single basis set orbital ($2p_z$) for ligands. The calculated dipole moments for these complexes are in agreement with the experimental values.

• Journal of Korean Society of Steel Construction
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• v.14 no.2
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• pp.357-364
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• 2002

The study performed a series of flexural tests on Closed Cold-Formed Steel Sections for stud, joist, and roof truss. Results were compared with analytical values. Each 2.4-m long and 0.9-m wide specimen consisted of two steel beams set at 0.46 m interval. The steel beams were attached to the specimens using either plaster board or ply wood. Another specimens did not use any attachment material. Positive and negative bending tests were conducted to investigate the composite behavior, including the effects of plaster board or ply wood on the buckling behavior of steel beam. Full-scale roof truss tests were also performed to study the buckling behavior and failure mode of the truss members.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.4
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• pp.145-154
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• 2006

This paper presents a method to enhance the load carrying capacity for a two-span continuous steel-concrete composite beam strengthened with external tendons. The tendon is placed at the bottom of steel beam where the positive bending moment occurs. This results in the reduction of the negative bending moment as well as the positive bending moment. This paper describes the procedure to determine the number of tendon and the initial tendon force for the target rating factor in the rating factor equation. An example beam is given to demonstrate the proposed procedure, and it validity is confirmed.