• Journal of the Korean Society of Manufacturing Process Engineers
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• v.12 no.4
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• pp.108-113
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• 2013

Industrialization and modernization of the beginning of the IT industry is growing very fast. Since telecommunications industry was developed rapidly, technologies about miniaturization and high-precision of parts have been actively developed to lead information revolution. generally, the entire shear surface of the product applying fine blanking technology must be very precise. Fine blanking is used to save cost by avoiding post-processing of the product. When using press blanking, it spends a lot of money on the production by using many post-processing. Fine blanking typically used in 0.5~18 mm thick steel plate. Because a lot of post-processing cost can be used to process, except for fine blanking. In order to develop components "CHANCE CONTENTS" in the fine blanking process, the purpose of this study is to minimize the edge of the bridge, secured 95% of the material thickness of the shear surface using the 1.6 mm thickness of the material SPCC. Blanking process by introducing after changing thickness through forging process, due to change in vee-rring force and counter force, the experimental amount of depressions and flatness and the shear surface were analyzed.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.928-931
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• 2006

Due to their light weight, high stiffness-to-weight and strength-to-weight ratios, and potentially high resistance to environmental degradation, resulting in lower life-cycle costs, polymer composites, are increasingly being considered for use in civil infrastructure applications. Recently, an FRP deck has been installed on a state highway, located in New York State. In this study, a thermal stress analysis was conducted using finite element method to study failure mechanisms of the superstructure. This analysis evaluated small and large temperature gradient effects on the FRP deck considering lightweight of FRP deck and ply orientations at the interface between steel girders and FRP deck Finite element model was verified using the load tests of the bridge deck. Finally, the analytical results shows the possible failure mechanism of FRP deck under various temperature changes and its corresponding index is suddenly varied depending on the rapid change of temperature on the deck plate.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1158-1164
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• 2007

Recently, the demand on the practical application of life-cycle cost effectiveness for design and rehabilitation of civil infrastructure is rapidly growing unprecedentedly in civil engineering practice. Accordingly, it is expected that the life-cycle cost in the 21st century will become a new paradigm for all engineering decision problems in practice. However, in spite of impressive progress in the researches on the LCC, so far, most researches in Koreahave only focused on roadway bridges, which are not applicable to railway bridges. Thus, this paper presents the formulation models and methods for uncertainty-based LCCA for railroad bridges consideringboth objective statistical data available in the agency database of railroad bridges management and subjective data obtained form interviews with experts of the railway agency, which are used to anew uncertainty-based expected maintenance/repair costs including lifetime indirect costs. For reliable assessment of the life-cycle maintenance/repair costs, statistical analysis considering maintenance history data and survey data including the subjective judgments of railway experts on maintenance/management of railroad bridges, are performed to categorize critical maintenance items and associated expected costs and uncertainty-based deterioration models are developed. Finally, the formulation for simulation-based LCC analysis of railway bridges with uncertainty-based deterioration models are applied to the design-decision problem, which is to select an optimal bridge type having minimum Life-Cycle cost among various railway bridges types such as steel plate girder bridge, and prestressed concrete girder bridge in the basic design phase.

• Journal of the Korean Society for Advanced Composite Structures
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• v.2 no.2
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• pp.20-25
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• 2011

In this paper, two dimensional concrete slabs for a railroad bridge were analyzed by the specially orthotropic laminates theory. Both the geometrical and material property of the cross section of the slab was considered symmetrically with respect to the neutral surface so that the bending extension coupling stiffness, $B_{ij}$ = 0, and $D_{16}=D_{26}=0$ Bridge deck behaves as specially orthotropic plates. In general, the analytical solution for such complex systems is very difficult to obtain. Thus, finite difference method was used for analysis of the problem. In this paper, the finite difference method and the beam theory were used for analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.7
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• pp.2702-2707
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• 2010

The load distribution factor (LDF) values of new composite I-beam panel bridges that were subjected to dead load were investigated using three-dimensional finite element analyses with the computer program ABAQUS(2007). This study considered some design parameters such as the slab thickness, the steel-plate thickness, and the span length for design of new composite bridges. The distribution values that were obtained from these analyses were compared with those from the AASHTO Standard, AASHTO LRFD, and the equations presented by Tarhini and Frederick, and Back and Shin. For the simple application of the design, bridge engineers can use the LDF of 0.67 for the exterior girder and of 0.340 for the interior girder.

• Earthquakes and Structures
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• v.11 no.4
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• pp.681-699
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• 2016

Steel box girders have two webs and two flanges on top that are usually connected with shear connectors to the concrete deck and are also known as tub girders. The end diaphragms of such bridges comprise of a stiffened steel plate welded to the inside of the girder at each end. The diaphragms play a major role in transferring vertical and lateral loads to the bearings and substructure. A review of literature shows that the cyclic behavior of diaphragms under earthquake loading has not been studied previously. This paper uses a nonlinear finite element model to study the behavior of the end diaphragms under gravity and seismic loads. Different bearing device and stiffener configurations have been considered. Affected areas of the diaphragm are distinguished.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.544-551
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• 2003

Despite the number of steel bridges being under in service more than 50 years reaches about $50\%$ in present, the Quantitative estimation in maintenance on steel railway bridges is not possible because a ton of the field data in the bridges have not been plentifully accumulated. Therefore a series of field tests on the steel plate girder bridge and steel truss bridge, the typical types of steel railway bridges, are executed, and the stress characteristics according to the structural types of the bridges are Quantitatively estimated in this study.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.04a
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• pp.326-331
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• 2009

An algorithm is proposed for computing dynamic displacements of a bridge using FBG sensors. An existing algorithm for estimating dynamic displacements of a simply supported beam through mode superposition is extended and applied to various types of bridges with bending and torsional modes. The proposed algorithm is examined through field tests on a suspension span steel deck plate box girder bridge. Guidelines are provided for determining the number of modes and the number of strain gages to be used.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.549-556
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• 2006

Life cycle cost is one of important factors in the evaluation of economy feasibility. Load carrying capacity curves for girders and decks are derived on the basis of bridge diagnostic results and condition grade curves to determine the service life and life cycle profile. The total life cycle costs including initial cost, damage cost, maintenance cost, user cost, and etc for the service life are calculated for steel box girder, PSC-I girder and rationalized plate girder. The optimal designs are performed for various service lifes and different superstructure types. The effects of parameters on the life cycle cost are investigated and the economy feasibility is evaluated through the sensitivity analysis.

• The Journal of the Korean dental association
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• v.11 no.4
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• pp.267-269
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• 1973

The authors had a case report of radicular cyst on left maxillary lateral incisor root apex region. Left maxillary central incisor, lateral incisor, canine was extracted, cyst was curetted. The prosthodontic treatment was good clinical results applying fixed bridge and the gum plate of resin in the case of massive alveolar bone loss.