• Journal of Korean Society of Steel Construction
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• v.18 no.4
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• pp.447-456
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• 2006

In this study, a torsional test for U-type steel box girders was performed to observe the effects of the kind of panel for top lateral walateral bracings on the torsional behavior of the U-type steel girder system. For the structural tests, the test specimen with a two-thirds scale of the system actually constructed in the field was used. In the torsional test to observe the efects of top lateral bracings, the most economical arrangement of the top lateral bracing was found to be the panel width to length ratio of 1:1.5 with the inclined angle of $40^{\circ}$.

• Journal of Korean Society of Steel Construction
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• v.24 no.2
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• pp.175-188
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• 2012

A parametric study for varying the radii of curvature is performed with a curved tub girder bridge having three continuous spans. The bracing forces of top lateral bracings from the results of numerical equations are compared to those of 3-dimensional finite element analyses. New modifying factors applicable in computing the nominal member forces of top lateral bracings were suggested. The numerical equations were derived based on one girder system, and it is shown that the numerical equations exhibit some errors compared with 3D FEA results. The main reason for this phenomenon lies on the number of girders. The twin girder system has an external cross-beam between inner and outer girder. It also has larger lateral stiffness than the single girder system. Finally, the distributions by the torsion, bending, distortion, and lateral loading of the top lateral bracing forces were presented in this paper.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.1
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• pp.68-76
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• 2007

In the present study, tests for U-type steel box girder are performed to observe the effects of W-type and X-type of top lateral bracings on the bending behavior of the U-type steel box girder system. Another objective of the present study is to investigate the adequacy of the currently available design formula. For the structural tests, the test specimen with two third scale of the system constructed in the field was used. In this test, several different spacings are used for the top lateral bracings. The stresses measured from the bending tests are compared with those by the formula proposed by Helwig. An adequate type and the required number of panel for diagonal bracing was obtained.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.41 no.3
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• pp.201-208
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• 2021

In this paper, the effect on the lateral and torsional behavior of ballastless railway plate girder bridge by the installation of the lower horizontal bracing has been reviewed. First of all, the most efficient lower bracing arrangement has been reviewed by comparing and examining the lateral displacement due to the train load, targeting analysis models with different arrangement types of lower bracing. Next, the research on torsional behavior of plate girder bridge with lower bracing has been conducted. In addition, the torsion constant from FEM analysis results has been compared with the torsion constant of a railroad plate girder bridge with a closed section by substituting the upper and lower horizontal bracing with equivalent thickness. Based on this comparison, the impact on the bridge span length and the cross section area of the lower bracing has been examined. Through this study, the curve graph related to lateral buckling moment and torsional constant ratio is presented and the range of plate girder bridge requiring torsional reinforcement is proposed.

• Journal of Korean Society of Steel Construction
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• v.19 no.3
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• pp.281-290
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• 2007

In this paper, the dynamic behavior of a 12m plate girder railway bridge is analyzed using the commercial FEM program. A time history load is applied to a standard train load via the shape function ofthe beam element. In addition, lateral behavior characteristics were simulated using the Klingel sine movement. A feasibility study of the FEM program and an analysis were performed by comparing the displacement and the acceleration, from the experimental data and the results of the FEM analysis. the time history of the lateral and vertical displacements are reflected in the experimental results. Six kinds of reinforcements were studied from the effects of the displacement and the acceleration. The RF-1 model that was applied to the upper lateral bracing system, and the RF-3 model that reinforced the plate, turned out to be the most effective reinforcement methods with respect to weight limits and construction simplification.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.4A
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• pp.299-305
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• 2009

In this study, in order to research the causes lead to fatigue crack in the coped stringer of a steel railway bridge, we take the steel railway bridge which actually occurs fatigue crack as a research object and manufacture the full size of crossbeam-stringer and floor system model to perform the experimental test. The results indicates that, the fatigue crack in the top of coped area of stringers is caused by the reciprocal action of the in plane stress in the tip of coped area of web by the negative moment occurred in the end of the stringers. While the fatigue crack in the bottom of coped area of stringers is due to the plane stress caused by the out-plane deformation relative to the bottom of coped area of web of the fixed end in the stringers.