• Journal of the Korean Society of Hazard Mitigation
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• v.4 no.4 s.15
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• pp.63-71
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• 2004

The centroid of rail doesn't coincide with the centroid of stringer on target truss bridge. If there is no eccentricity on the bridge, bending stress works only. But in the real design and execution, not only bending stress works but also torsional stress does because of it's eccentricity. So this study evaluates how much the torsional stress by eccentricity effects joint members on the bridge. We investigate the possibility to control torsional stress if we model longitudinal bracing between stringers.

• Structural Engineering and Mechanics
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• v.59 no.4
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• pp.683-701
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• 2016

Safety is the prime concern for a high-speed railway bridge, especially when it is subjected to a collision. In this paper, an analysis framework for the dynamic responses of train-bridge systems under collision load is established. A multi-body dynamics model is employed to represent the moving vehicle, the modal decomposition method is adopted to describe the bridge structure, and the time history of a collision load is used as the external load on the train-bridge system. A (180+216+180) m continuous steel trussed-arch bridge is considered as an illustrative case study. With the vessel collision acting on the pier, the displacements and accelerations at the pier-top and the mid-span of the bridge are calculated when a CRH2 high-speed train running through the bridge, and the influence of bridge vibration on the running safety indices of the train, including derailment factors, offload factors and lateral wheel/rail forces, are analyzed. The results demonstrate that under the vessel collision load, the dynamic responses of the bridge are greatly enlarged, threatening the running safety of high-speed train on the bridge, which is affected by both the collision intensity and the train speed.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.338-350
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• 2010

As existing materials for ground reinforcement, chemical grout material using cementitous materials and waterglass was used. But many problems in terms of ground reinforcement effects were implicated. In this study, for development and applicability verification of new materials, viscosity, fluidity, permeability, Self-Leveling, keeping of drilled hole, antiwashout underwater, resistance of water (groundwater dilution and minimize material eluting) and the early strength and long-term strength characteristics of developed materials was confirmed, and material standards, and establishing construction standards for the various model tests were conducted. As a result, high viscosity, flowability, permeability and keeping of drilled hole characteristics are excellent, in addition to the early strength properties, dilution does nat occur to groundwater, including groundwater is available for dealing with environmental issues. Application of basic and reinforcement method by Filler function in addition to structure can also or development of a new concept can be expected. In addition, middle and large-diameter drilled shaft, micropile, ground anchors, soil-nailing, steel pipes multi-grouting reinforcement for cement injection process could be used enough to even be considered.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1697-1702
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• 2010

It has been recognized for decades that the spherical bearing which is sliding on curved surface in the intrinsic behavior is optimized for the railway bridge requiring a large slope deflection. However, the spherical bearing is easily corrosived at the PSC girder bridge which is exposed to the outside so the normal function of bridge bearing is not fulfilled fully. It is common that the corrosion is happened at the operating plate of steel bridge bearing and generally it is necessary to replace the bridge bearing after 20~25 years. Accordingly, It costs multi billion dollars for maintenance each year and the necessity of improvement become a issue. Korea Rail Network Authority(KR) suggested to apply the Elastomeric bearing instead of Spherical bearing through the task of construction site of 2006. But the normal Elastomeric bearing is optimized for the Highway bridge so it needs the special consideration to satisfy each design condition required by railway bridge. As the result of examination of Elastomeric bearing at the railway bridge construction site, the stress is decreased by effective dispersion of earthquakes and the maintenance fee is also decreased.

• Special Issue of the Society of Naval Architects of Korea
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• 2008.09a
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• pp.90-95
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• 2008

The letters and marks on the hull of vessels are marked by welding bead or steel plate to resist the corrosion environment. It has done by manual work. So, it cause deterioration of welding quality and process delay and so on. The automated welding device for draft mark has developed partially in the field of shipbuilding. But it can be used for draft mark only. And it has caused a few problems about that workablity and movablity are decreased owing to the size and weight of device. So we developed the automated welding device that can be used for most letters and marks on the hull. It designed to 3 axises mobile robot include to ratoation axis and stand alone type controller with multi GUI base on imbedded windows.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.46-55
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• 2008

Maglev is a system that a train runs levitated above a rail. Therefore it is very important to maintain a constant levitation gap for achieving serviceability and ride comfort. This study is a cooperation research subject of the 3-1 subject, performance improvement of maglev track structures, of the Center for Urban Maglev Program in Korea, started in 2006. The aim of this study is development of rapid constructions of bridge superstructure for maglev. At present, precast deck is widely used because of its superiority to cast-in-place concrete on quality and the term of works. The research group suggested basic systems of maglev guideway with PSC-U type and trapezoidal open steel box type girder, and precast deck, cooperating with Korea Railroad Research Institute, the managing institute of the 3-1 subject. In this study, longitudinally full-scale guideway girder system was fabricated and static/dynamic test of the girder was performed for the purpose of the performance evaluation.

• Journal of the Korean Society for Railway
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• v.9 no.1 s.32
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• pp.43-49
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• 2006

We have evaluated the structural integrity of a sandwich composite train roof structure that can be a lightweight, cost saving solution to large structural components for rail vehicles in design stages. The sandwich composite train roof structure was 11.45 meters long and 1.76 meters wide. The finite element analysis was used to calculate the stresses, deflections and natural frequencies of the sandwich composite train roof against the weight of air-conditioned system. The 3D sandwich finite element model was introduced to examine the structural behavior of the hollow aluminum extrusion frames joined to both sides of the sandwich composite train roof. The results shown that the structural performance of the sandwich composite train roof under loading conditions specified is satisfaction and the use of aluminum reinforced frame and aluminum honeycomb core is beneficial with regard to weight saving and structural performance in comparison with steel reinforced frame and polyurethane foam core. Also, we have manufactured prototype of sandwich composite train roof structure on the basis of analysis results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.852-857
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• 2011

The shipbuilding industry needs automation and mechanization to solve reduction of skilled workers and labor shortage. Ship manufacturing process is the lack of automation than standardized manufacturing field. In this paper, we design and development an process automation system for hand rail production. Mechanical parts of the cutting process was designed with efficiency, productivity and reliability, CATIA and ANSYS, the stability of the mechanical structure was confirmed. System control using a PCNC controller to provide an open and scalable, and operate using touch-screen display control and monitoring of the system was performed. The automatic system successfully passed the driving test and processing test, and it showed an excellent performance.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1609-1611
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• 2007

The owner of underground metallic structures (gas pipeline, oil pipeline, water pipeline, etc) has a burden of responsibility for the corrosion protection in order to prevent big accidents like gas explosion, soil pollution, leakage and so on. So far, Cathodic Protection(CP) technology have been implemented for protection of underground systems. The stray current from DC subway system in Korea has affected the cathodic protection (CP) system of the buried pipelines adjacent to the railroads. In this aspect, KERI has developed a various mitigation method, drainage system through steel bar under the rail, a stray current gathering mesh system, insulation method between yard and main line, distributed ICCP(Impressed Current Cathodic System), High speed response rectifier, restrictive drainage system, Boding ICCP system. In this paper, the mechanism of mitigation method of DC stray current for underground metallic structures is described.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1612-1614
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• 2007

The owner of underground metallic structures (gas pipeline, oil pipeline, water pipeline, etc) has a burden of responsibility for the corrosion protection in order to prevent big accidents like gas explosion, soil pollution, leakage and so on. So far, Cathodic Protection(CP) technology have been implemented for protection of underground systems. The stray current from DC subway system in Korea has affected the cathodic protection (CP) design of the buried pipelines adjacent to the railroads. In this aspect, KERI has developed a various mitigation method, drainage system through steel bar under the rail, a stray current gathering mesh system, insulation method between yard and main line, distributed ICCP(Impressed Current Cathodic System), High speed response rectifier, restrictive drainage system. We installed the mitigation system at the real field and test of its efficiency in Busan and Seoul, Korea. In this paper, the results of field test, especially, distributed ICCP system is described.