• The Transactions of the Korean Institute of Electrical Engineers B
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• v.51 no.7
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• pp.357-363
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• 2002

The target reliability values are defined for the train, signaling, rail track and electric power supply system of the LRT under development. The allocation of the reliability value is based on the failure rate and the failure type in the Korean subways. The reliability allocation in the train system is the made ore detail than others. The purpose of the allocation is to verify the reliability value of the results from each of the development stage, which could be the designing, manufacturing and purchasing work. The reliability of braking system, traction system, door system and other control system could be verified by establishing reliability models of these system. It could also enable us to estimate and analyse the reliability value and redo the work if necessary to achieve the shooting reliability value. A guide to the LRT reliability criteria is to be prepared after running test on the test track.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.1146-1152
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• 2005

Now many metropolitan electric railways are being constructed on the metropolitan area. But railways now in service have some inefficiency. These railways are operated like subways, for example, all slow trains and fixed train set. So this paper proposes the methods of improvement. For making rapid train, it is showed ' philosophy of rapid train ' that makes rapid train to be main service. And for effective operation, it is introduced flexible train set and 'separation-unification operation'. And for smart railway tracks, it is introduced making loop track and direct connection track between radiating and circular railways. By these methods, a master plan of improvement of metropolitan electric railways is made and vision of the railways becomes common to passengers.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1085-1090
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• 2007

In recent railway construction, the concrete slab track is getting highlighted as main stream in track type. However, it is the fact that there are different opinions in selection of the optimized spring coefficient of elastic pad. In this study, the performance of vibration reduction in different stiffness of rail pad for ballasted track was compared, and the changes in characteristics, such as static/dynamic deflection of components, vibration acceleration, insertion loss etc., were analysed by using ISI Program for various types of rail fastening system used in concrete slab track. It was concluded that the fastening system with softer pads has shown the better performance of vibration reduction in concrete slab track and the optimized static stiffness has been calculated to 21.1kN/mm for conventional railways, 17.6kN/mm for high-speed railways and 17.8kN/mm for subways.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1371-1375
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• 2010

Recently, the Seoul Metro has replaced the old series of Line No.2 and 3 to the new ones. In spite of the replacement, the new ones are more likely to be slippery compared to the old ones. Because the subway system has such short intervals, delayed subways influence the whole line systems, especially during the rush hours. And the slip causes the delay. Therefore we are willing to find out the reason why the new ones are more defective and we will try to mince it from the view of mechanical aspects and handling aspects of driving.

• Steel and Composite Structures
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• v.22 no.5
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• pp.1141-1162
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• 2016

Concrete-filled double skin steel tube (CFDST) beam-columns are widely used in industrial plants, subways, high-rise buildings and arch bridges. The CFDST columns have the same advantages as traditional CFT members. Moreover, they have lighter weight, higher bending stiffness, better cyclic performance, and have higher fire resistance capacities than their CFT counterparts. The scope of this study is to develop finite element models that can predict accepted capacities of double skin concrete-filled tube columns under the combined effect of axial and bending actions. The analysis results were studied to determine the distribution of stresses among the different components and the effect of the concrete core on the outer and inner steel tube. The developed models are first verified against the available experimental data. Accordingly, an extensive parametric study was performed considering different key factors including load eccentricity, slenderness ratio, concrete compressive strength, and steel tube yield strength. The results of the performed parametric study are intended to supplement the experimental research and examine the accuracy of the available design formulas.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.199-204
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• 2001

Big accidents of flyings, vessel, subways, gas equipments, buildings and bridge happens frenquently. Therefore many people are suffering harm of property. The destruction cause of macaine components is almost accused by fatigue. This study is test for STS304 specimen using pure and cantilever bending state. Rounded specimen and notched specimen including fracture surface investigation was comparatively experimented, fatigue life according to degree of surface finishing was examined. Fatigue fracture probability of notched canilever specimens were predicted by P-S-N curve, median rank and Weibull distribution. And at the relation with the rotational speed and stress, the fatigue life of the test specimen was higher at high speed than low speed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.724-729
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• 2003

Installing vibration isolation in structures, such as structures adjacent to subways, may be delicatebecause of the proximity with the vibration source or because of the wave propagation path. This paper discusses on method that install isolation Pads on underground walls as a part of the vibration mitigation system, and also on its efficiency, The proposed method is proven to affect significantly the distribution of acceleration in the neighborhood of the structure and to reduce efficiently the maximum amplitude of the vibration. It is also seen that installing isolating pads until the depth of the foundations and deeper is more efficient than installing such device separately from the structure. This Study being limited to the comparison of installation methods, further Studies considering the thickness, stiffness and other parameters should be required.

• Journal of the Korean Society for Railway
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• v.10 no.4
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• pp.420-430
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• 2007

It is reported that many users of the subways in Seoul are not currently satisfied with the subway services. The cause of the dissatisfaction is that the qualitative items and indexes are not considered properly, and also does not diversify the evaluation items to follow the change of subway environment. Therefore in this study the evaluation items and indexes that can reflect of the subway users' characteristics are examined and synthesized. Then the characteristics of service are analyzed for the senior subway system users and junior subway system users that are classified with the cluster analysis. The result of the study is that the majority of users on subway are not satisfied the qualitative items which are safety, kindness, comfortableness, convenience excepting for punctuality and accessibility. So, if the service of subway users improve, the qualitative items is needed to consider with quantitative items.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.1197-1200
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• 2003

Urban subways usually make environmental problems because subway vibrations are transmitted to building structures. However, when the buildings are designed, vibrations due to subway are not usually considered in advance. This results in many environmental vibration problems after buildings are constructed. This study was carried out to set up and evaluate a pre-assessment technique for the environmental impact of urban subway vibration on newly planned buildings near a subway line. for this purpose, semi-emperical method was set up and vibration measurements were made on site in accordance with construction schedule. Computer simulation was also performed using ANSYS software to predict the building vibration and compared with the measured results for evaluation of the pre-assessment technique.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.957-964
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• 2004

The selected structure for the value engineering review is one section of cut and cover tunnel for Seoul Subway Line 9. The primary focus of the review is on the optimisation of the structures to save cost on the existing Line 9 contracts through variation of the design criteria as it affects the permanent works. This is to be achieved through comparison with design criteria for other selected international subways. Criteria resulting from the review must not compromise public safety and durability for the 100 year design life.