• Journal of Korean Society of Steel Construction
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• v.17 no.5 s.78
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• pp.593-604
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• 2005

In this paper, the parametric study on the local displacement and the local moment due to a concentrated load is performed for stiffened plates with open ribs and the orthotropic rigidity ratio of stiffened plates is selected as the parameter. For estimating the local behavior, stiffened plates loaded on the center of plates between the ribs were considered and for the global behavior, stiffened plates loaded on the rib at the center of plates were analyzed. The Analyzed results for the local behavior of stiffened plates show that the increasing ratio of the local moment according to rib sizes is constant regardless of rib spaces and the ratio of the local displacement to the global displacement can be expressed as a function of the rib space and the rigidity ratio. The application of functions to examples shows good accuracy in comparison with the local behavior of stiffened plates loaded on the center of plates and the application to the orthotropic analysis of stiffened plates improves accuracy. Therefore, using functions proposed in this study, the local behavior can easily be estimated from the global behavior of stiffened plates with open ribs.

• Journal of Korean Society of Steel Construction
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• v.24 no.6
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• pp.659-670
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• 2012

The purpose of this study is to formulate the local displacement and moments of a plate stiffened with open ribs according to the dimensions of stiffened plates. Analyzed results of various plates stiffened with rectangular and reverse T ribs show that the effect of the lower flange to the local behavior is very small, so the local behavior can be expressed by ratio functions of the rib space, web thickness, web height and plate thickness and the ratio functions of rectangular and reverse T ribs can be unioned. The application of ratio functions to other types of stiffened plates shows that the increment of the error ratio is so small compared with examples of this study that the applicability of this study is proved.

• Journal of Korean Society of Steel Construction
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• v.25 no.3
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• pp.267-278
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• 2013

In this study, stiffened plates with open ribs are analyzed to estimate and formulate the local displacement and local moments according to square loading sizes. For the local behaviors of plates stiffened with rectangular and reverse T ribs, the ratio functions according to the dimensions of stiffened plates are obtained at each square loading size. Analytical results show that values of the basic stiffened plates are different but the ratio functions of each square loading size are similar and the difference of the ratio functions between rectangular ribs and reverse T ribs are small, so the ratio functions can be unified by integrating the loading sizes regardless of the rib type. The application of the unioned ratio functions to L type ribs and rectangular loading shows good accuracies. Therefore, the local behaviors of plates stiffened with open ribs can easily be obtained by using the unioned ratio functions proposed in this study.

• Geotechnical Engineering
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• v.9 no.1
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• pp.31-44
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• 1993

Model tests in calibration chamber with open -ended steel pipe pile have been performed in sand deposit to clarify effect of soil plug on bearing capacity, load transfer mechanisms in soil plug, and behavior of soil plug under dynamic and static conditions. Model piles were devised so that bearing capacity of open -ended pile could be measured separately into outside skin friction, inside skin friction due to soil plug -pile interaction and end bearing force on the section of steel pipe pile. It may be concluded, form the test results, that the plugging level of open -ended pile is more correctily defined by specific recovery ratio, y, rather than by plug length ratio, PLR, and the major part of inside skin friction is generated within the range of three times as long as the inner diameter of the pile from the pile tip. The ratio of inside skin friction to total bearing capacity is much larger than that of outside skin friction to total bearing capacity. Therefore, the bearing capacity of pile could not be well predicted, unless the inside skin friction is properly taken into account.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.14 no.2
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• pp.107-116
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• 2001

복합재 적층판은 중량에 비해 높은 강성과 강도가 요구되는 공학의 다양한 분야에서 매우 유용하다. 보강섬유 복합재의 공학적 활용이 활발해지고, 중량의 감소화가 설계의 중요한 목적이 됨으로써, 근래 복합재 구조물들의 최적화 설계의 중요성이 대두되고 있다. 그러나 복합재 적층 구조물 재료의 비등방성에 의해 해석과 설계가 매우 어렵다. 본 연구에서는 수치적 최적화 방법과 유한요소법을 이용하여 보강섬유 복합재의 최적설계를 하였다. 복합재 적층판으로 이루어진 개단면 보에 있어서 보강섬유의 다양한 적층방향에 대한 거동의 영향을 규명하였다.

• Proceedings of the KAIS Fall Conference
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• 2011.05b
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• pp.608-610
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• 2011

본 논문에서는 자동차의 도어의 충격봉의 형상에 따른 변형률과 최대응력을 ANSYS Workbench환경을 이용해 원형, 반원형, 모자형 개단면, 정사각형 등의 단면 형상에 따른 변형량 특성을 측정해 본 결과 변형률은 모자형 개단면 모델이 가장 적은 변형률을 가지는 것으로 나왔으며, 무게가 30%정도 적게 나가는 반원형도 두 번째로 적은 변형률을 가지는 것으로 나타났다. 최대응력의 경우는 반원형이 가장 적은 최대응력 값을 가지는 것으로 나왔고, 변형률과는 다르게 중심부 보다는 충격봉과 프레임의 연결부위에서 최대응력이 발생하는 것을 알 수 있었다. 이를 통해서 충격봉의 중심부는 변형률 및 응력이 다른 부분에 비해서 크게 작용하므로, 중앙부위의 단면계수가 높아야 한다.

• 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 Korean Society of Steel Construction
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• v.17 no.1 s.74
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• pp.23-32
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• 2005

In this paper, the modified coefficient of the orthotropic rigidity for stiffened plates with open ribs is proposed to improve the inaccurate results of the orthotropic plate analysis. For stiffened plates with rectangular and angle ribs having various aspect ratios and boundary conditions, the aspect ratio and the rigidity ratio are selected as parameters and the parametric study on the modified coefficient is performed. Analyzed results of stiffened plates modeling with the isotropic and orthotropic plate element show that the modified coefficient can be expressed as a function of the rigidity ratio for each rib space regardless of the aspect ratio in case of the aspect ratio under 1 and can be represented as a single union function without regard to rib spaces and aspect ratios in the other case. The results also shows that the effects of the boundary condition on the modified coefficient is small and coefficient functions have different values according to rib shapes. The application to examples shows that the modified coefficient of the orthotropic rigidity improves accuracy. Therefore, the orthotropic plate analysis of stiffened plates with open ribs can easily achieve more accurate results using the coefficient function proposed in this study

• Journal of Korean Society of Steel Construction
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• v.14 no.6
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• pp.701-710
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• 2002

An analysis program using orthotropic plate elements was developed to simplify the analysis of plates stiffened with open ribs and the orthotropic behavior of stiffened plates and the application of this program were evaluated using the sensitivity analysis and the parametric study. The inertial moment ratio, i.e., the ratio of the inertial moment of the rib to that of the plate was defined and the orthotropic behavior of stiffened plates corresponding to the inertial moment ratio was proved by the sensitivity analysis. To evaluate the application of this program, the parametric study for various types of stiffened plates was performed and then the maximum displacement of this study was compared to that of ABAQUS using isoparametric plate elements. The Results of this study agreed well with that of ABAQUS at the particular inertial moment ratio, that is proposed to the limit ratio of the orthotropic plate analysis and the correlative function between the error ratio and the inertial moment ratio was obtained. Therefore, the orthotropic plate analysis of stiffened plates with open ribs could have safe results over the limit ratio and also have good results simply by using the correlative function of this study.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.2
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• pp.33-44
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• 2013

Although many studies have been performed for the structural details of orthotropic steel deck, most of them were focused on the trough rib of standard type, but not for orthotropic steel deck with longitudinal rib of open section used at beginning of the deck. In order to investigate the cause of fatigue crack for orthotropic steel deck bridge serviced 31 years with longitudinal rib of open section, in this study, the behavior characteristics of target structural details were analyzed based on measurement data under real traffic condition. Also the typical loading truck passing the target bridges was estimated with the structural analysis detailed, and the stresses and deformation patterns of target structural details were analyzed by performing the detailed structural analysis. Based upon the analysis, retrofitting methods of the fatigue crack were suggested and its validation was examined. From this study, it was clarified that fatigue crack of longitudinal rib with open section were affected with the stress increment by shear deformation in the rib and the occurrence of alternative stress due to moving vehicle. In addition, it was known that it is important to perform fatigue design reflected the local behavior of the structural details.