• Journal of Korean Society of Steel Construction
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• v.18 no.5
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• pp.563-574
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• 2006

The objective of this study is to determine the effect of the loading size on displacements of stiffened plates with open ribs using the orthotropic rigidity ratio as the parameter. To analyze the displacement behavior of stiffened plates according to the loading size, a concentrated load and three types of uniform distributed loads were applied on the rib at the center of some plates. The results of the analysis of various stiffened plates show that the central displacement ratio of the distributed load to the concentrated load increased according to the decrease in the loading size, and that the ratio can be expressed as a function of the rigidity ratio for each rib space. The maximum displacement of the stiffened plate subjected to the distributed load did not appear at the center of the plate due to the local behavior, and the increasing ratio of the maximum displacement to the central displacement can be expressed as a function of the rigidity ratio for each rib space. Orthotropic plate analysis can achieve more accurate results using the proposed functions, and the application of the functions to examples of a different aspect ratio and support condition shows good accuracy. Therefore, using the functions proposed in this study, the central and maximum displacements can easily be achieved in the orthotropic plate analysis of stiffened plates subjected to the distributed load.

• Journal of Korean Society of Steel Construction
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• v.16 no.2 s.69
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• pp.191-200
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• 2004

In this paper, the modified method of orthotropic rigidities for stiffened plates with open ribs is proposed to solve the problem of the inaccurate results of the orthotropic plate analysis according to the dimensions of stiffened plates. In analyzing various types of stiffened plates with open ribs using the isotropic and orthotropic plate element, orthotropic plates are found to gave smaller maximum displacements compared to isotropic plates in a range that is smaller than the special rigidity ratio and reversely. Therefore, obtaining a more accurate solution of the orthotropic plate analysis requires modifying the orthotropic rigidities of stiffened plates according to the rigidity ratio. This study presents two modified methods using the displacement function and the displacement ratio. The application of the two methods improves the accuracy of the results of the orthotropic plate analysis, although the modified method using the displacement ratio is better than the method using the displacement function in terms of serviceability and safety. The comparison with the experimental example shows that the proposed modified method improves accuracy. Therefore, the orthotropic plate analysis of stiffened plates with open ribs can achieve more accurate results using the proposed method in this study.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.5
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• pp.24-31
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• 2021

The soundproof tunnels have been generally designed with H-beam girders, and the high weight of H-beam may cause the excessive design of the substructure. To solve this problem, this paper proposes a new soundproof tunnel girder design composed of pipes and discontinuous plates. First, the structural behavior of the straight girder according to the design parameters was examined through finite element analysis. The arrangement and shape of the plates were determined as the design parameter, to obtain the optimal design of girder. After then, the structural behavior and buckling stability of the arched girder were subsequently evaluated. As a result of the parameter analysis, it was confirmed that the axial force acting on the girder increased and the moment decreased as the ratio of unsupported sections decreased or the number of supporting plates increased. The stress concentration on the pipe member was relieved by increasing the long axis length of the elliptical plate. Arched girder analysis showed that the structural efficiency increase as the long axis of elliptical plate increase. As a result of the buckling evaluation, the buckling threshold load of the three connected girders was about 3.7 times higher than the design load. Consequently, it was confirmed that the proposed soundproof tunnel structure design satisfies both light weight and structural safety.

• Journal of Korean Society of Steel Construction
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• v.19 no.6
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• pp.621-632
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• 2007

The purpose of this study was the estimation and formulation of orthotropic flexural rigidities considering the deformed shape for a plate stiffened with rectangular ribs. Analytical results of methods modifying the flexural rigidity of the x-direction, the y-direction or both directions were compared at the center, the x-directional quarter point and the y-directional quarter point of stiffened plates loaded at the center. The composite method modifying the flexural rigidity of both directions improves the accuracy compared with the other methods. Moreover, the ratio of modified coefficients for each directional rigidity can be expressed as a function corresponding to each dimension of stiffened plates. The application of modified coefficient functions to various types of stiffened plates with different boundary conditions, aspect ratios and rib arrangement shows that the increment of the error ratio is small compared with examples of this study and the application of proposed functions shows more accurate results than previous methods modifying the flexural rigidity. Therefore, by using the modified coefficient functions proposed in this study, the orthotropic plate analysis of plates stiffened with rectangular ribs can easily achieve more accurate displacement results.