• Journal of the Korean Society of Safety
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• v.18 no.2
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• pp.132-138
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• 2003

The use of long rails in high-speed railway bridges causes additional stresses due to nonlinear behaviours between the rail and bridge decks in the neighbourhood of the deck joints. In the seismic response analysis of high-speed railway bridges, since structural response is highly sensitive to properties of the ground motion, spatial variation of the ground excitation affects responses of the bridges, which in turn affect stresses in the rails. In addition, it is shown that high-speed trains need very long distances to stop when braking under seismic occurrence corresponding to operational earthquake performance level so that verification of the safe stoppage of the train is also required. In view of such additional stresses due to long rails, sensibility of structural response to the properties of the ground motion and braking distance needed by the train to stop safely, this paper proposes and establishes a time domain nonlinear dynamic analysis method that accounts for braking loads, spatial variation of the ground motion and material nonlinearities of rails to analyze long rail stresses in high-speed railway bridges subjected to seismic event. The accuracy of the proposed method is demonstrated through an application on a typical site of the Korean high-speed railway.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1452-1459
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• 2010

Application of long-span bridge, which is affected by parameters such as span length, shoe boundary condition, track property and stiffness of superstructure and substructure etc., can vary. Especially, by CWR aspects of the axial force, that can be less constraints of construction depending on whether the application of rail expansion joint(REJ), which has disadvantaged in terms of maintenance. In this study, it was performed parameter study for multiple variables (shaft length, the upper and lower cross-section characteristics, track characteristics, etc.) in terms of CWR aspects. Structure-rail interaction analysis was applied to the typical simple span PSC Box and 3 span continuous bridge Extradosed Bridge(50m+80m+50m) excluding REJ. If you set the boundary e of variables for long-span railway bridge excluding REJ through the this study, when designing future is expected to be able to useful.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.13 no.6
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• pp.448-454
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• 2001

In the present study, the transient axi-symmetric numerical simulation of traffic ventilation induced by a train running through a 15.6km-long tunnel is performed by using over 100,000 computational cells. With train running, three cases of ventilation schemes are simulated, which are the case of ventilation fans turned on, the case of no fan but ventilation shafts open, and the case of no fan and no shaft. Results of the ventilation flow rate are pressure transients are compared for the cases considered.

• Structural Monitoring and Maintenance
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• v.1 no.4
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• pp.371-392
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• 2014

Long-span cable-supported bridges are flexible structures vulnerable to unsymmetric loadings such as railway traffic and strong wind. The torsional dynamic response of long-span cable-supported bridges under running trains and/or strong winds may deform the railway track laid on the bridge deck and affect the running safety of trains and the comfort of passengers, and even lead the bridge to collapse. Therefore, it is eager to figure out the torsional dynamic response of long-span cable-supported bridges under running trains and/or strong winds. The Tsing Ma Bridge (TMB) in Hong Kong is a suspension bridge with a main span of 1,377 m, and is currently the world's longest suspension bridge carrying both road and rail traffic. Moreover, this bridge is located in one of the most active typhoon-prone regions in the world. A wind and structural health monitoring system (WASHMS) was installed on the TMB in 1997, and after 17 years of successful operation it is still working well as desired. Making use of one-year monitoring data acquired by the WASHMS, the torsional dynamic responses of the bridge deck under rail traffic and strong winds are analyzed. The monitoring results demonstrate that the differences of vertical displacement at the opposite edges and the corresponding rotations of the bridge deck are less than 60 mm and $0.1^{\circ}$ respectively under weak winds, and less than 300 mm and $0.6^{\circ}$ respectively under typhoons, implying that the torsional dynamic response of the bridge deck under rail traffic and wind loading is not significant due to the rational design.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.371-379
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• 2010

Since Kyoto Protocol to the United Nations Framework Convention on Climate Change in 2005 takes effect, the transportation policies of most countries move toward encouraging the use of the transit mode with energy efficient and low carbon. Korea is 8th country of producing Co2 emissions and will be one of obligation countries decreasing Co2 after year 2013. In order to improve the efficiency of national transport system investment, this study developed the strategies toward rail-oriented transport system by considering operational speed and accessability, rail-oriented development, and introduce of ubiquitous technique in railway. The four major strategies targeted for future year are introduced here such as One-hour rail(connecting major cities within one hour), Seamless 30(accessing major railway stations within 30 minutes, Rail urbanism (railway-based urban planning), and U-rail (railway service with ubiquitous technique). Each strategy includes several action plans and their priorities are investigated using AHP(Analytic Hierarchy Process) to organize them by time scheme as short, mid, and long term perspective.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.960-966
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• 2022

Mobility is an essential human need. Human survival and societal interaction depend on the ability to move people and goods. Efficient mobility systems are essential facilitators of economic development. Cities could not exist and global trade could not occur without systems to transport people and goods cheaply and efficiently. Rail has been considered as one of the important components of the transportation infrastructure required to service and improve the performance and productivity of an economy. In Nigeria, the rail infrastructure built by the colonial master several decades ago has been left in a state of total deterioration. This long neglect was occasioned by the failure of the government to pay adequate attention to infrastructure development. There is a vital and urgent need for rail infrastructure development in Nigeria. This study presents a systematic review of the evolution of rail, the current nature of railway infrastructure delivery in Nigeria, and offers possible suggestions on how to achieve an effective and sustainable rail infrastructure delivery in Nigeria. A thorough literature search of academic databases was conducted on current research trends on the subject of railway infrastructure by systematically reviewing selected published articles from reputable research domains. The analysis of the selected articles revealed the following among others (1) the existing railway infrastructure is in a state of mess and not sustainable, and (2), Government's investment/commitment in rail infrastructure seems inadequate compared to what is obtainable in other developed countries. Rail infrastructure development cannot be left to the Federal government of Nigeria to solve on its own; collaboration and participation are required. Government as a matter of priority should devote considerable attention to the development of rail infrastructure to harness the economic potential and transformation that sustainable rail infrastructural projects will provide.

• Proceedings of the KSR Conference
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• 2011.05a
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• pp.1248-1253
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• 2011

It is increasing construction of long span railway bridge with concrete track system for speed up of railway and efficient maintenance of track. As the sleeper of the concrete track system layed on a bridge is fixed on deck of the bridge, the displacement of the sleeper and deck is same. Therefore, the spacing between two sleeper installed at the end of the adjacent deck near the expansion joint of bridge becomes vary according to the longitudinal expansion of a deck by temperature change. By the way, if the spacing of sleepers become increase excessively, it causes large bending stress of in a rail, and it can leads failure or reduction of fatigue life of the rail. Further more, the excessive displacement of the rail may induce decrease ride comfort as well as corrugation of rail surface. Therefore, it is required to determine the allowable maximum sleeper spacing to prevent such problems. For the purpose, investigation on the influence factor on sleeper spacing for straight track was carried out. Variation of bending moment in a rail, wheel force, and the ratio of primary and secondary deflection of the rail according to sleeper spacing was investigated, and, as a result, the maximum allowable sleeper spacing at the bridge expansion joint was suggested.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.119-125
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• 2000

In this study, field measurements and analysis of vibration before and after the installation of continuously welded rail were performed. The vibration data obtained at the same locations before and after were analyzed to find out the characteristics of vibration level. The component of train-induced impulsive vibration at the rail joints varies depending upon the distance from the source, however mostly low frequency vibration which propagates long distance causes the problems of vibration. Even though it is expected that there may be certain degree of discrepancy in the amount of reduction in vibration depending upon site ground conditions, it was found that installation of continuously welded rail shows reduction in train-induced vibration.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.74-82
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• 2001

This paper sets out what can be said in general about pricing within transport sectors. In this paper we briefly restate the economic principles of pricing that hold for two transport sectors-road and rail. This is used as a basis for a discussion of pricing principles in the transport sector. Here we focus on the pricing of user charges of transport infrastructures. We start this paper to analyse road transport sector and compare it with rail sector. In fact as a result of the trend towards rail reform, the issue of charging mechanisms for the use of rail infrastructure has become increasingly important. In this paper, we just take the problem in theory and present some foreign cases. But our long-run objective will be the design of efficient user charges of infrastructures based on fair intermodal competition.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.236-241
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• 2007

DC feeding system is mainly floating but the rail potential and the leakage current are created because of long parallelism between rails and ground. Rail potential causes electric shock to human and leakage current causes electrolytic corrosion to nearby the buried metals. Therefore the design technologies to reduce, protect and monitor these effects are important recent DC feeding system. Normally during designing DC feeding system in terms of rail potential and leakage current, there are about 10 parameters. Four design parameters among those is analysed based on propagation theory that is utilized in order to simulate grounding system.