• Proceedings of the KSR Conference
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• 2002.10a
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• pp.633-641
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• 2002

Wooden-sleeper, which has been adopted as railway turnout in Korea, has created many problems such as short life span and increase of maintenance cost. Especially turnout on Maintenance Free slab track, which has been used in city metro, has been constructed with wooden sleeper buried in concrete roadbed due to complexity of structure. However, such problem as rapid erosion in subground makes it difficult to maintain the sleeper because of frequent replacement required. Therefore, the objective of this paper is to introduce design and construction of reinforced concrete(R.C) sleeper for turnout on the concrete roadbed to facilitate maintainability and economic construction of turnout.

• Structural Engineering and Mechanics
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• v.41 no.2
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• pp.231-242
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• 2012

This research work aims to develop an optimal design using Finite Element (FE) and Genetic Algorithm (GA) methods to replace the traditional concrete and timber material by a Synthetic Polyurethane fibre glass composite material in railway sleepers. The conventional timber railway sleeper technology is associated with several technical problems related to its durability and ability to resist cutting and abrading action of the bearing plate. The use of pre-stress concrete sleeper in railway industry has many disadvantages related to the concrete material behaviour to resist dynamic stress that may lead to a significant mechanical damage with feasible fissures and cracks. Scientific researchers have recently developed a new composite material such as Glass Fibre Reinforced Polyurethane (GFRP) foam to replace the conventional one. The mechanical properties of these materials are reliable enough to help solving structural problems such as durability, light weight, long life span (50-60 years), less water absorption, provide electric insulation, excellent resistance of fatigue and ability to recycle. This paper suggests appropriate sleeper design to reduce the volume of the material. The design optimization shows that the sleeper length is more sensitive to the loading type than the other parameters.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.2
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• pp.34-42
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• 2018

In order to minimize the deformation of asphalt concrete track(ACT) and ensure the structural safety, a wide type concrete sleeper is necessary to distribute vehicle loading and reduce the exposure of the asphalt roadbed. In this research, the wide prestressed concrete(PSC) sleeper for ACT was developed through the shape design and the structural safety was reviewed using finite element analysis. Furthermore, static test, dynamic test and fatigue test were carried out according to EN13230-2 to verify the design appropriateness of the wide PSC sleepers for ACT. The performance test showed that the developed wide PSC sleeper for ACT meets all the performance requirements by European standard.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.478-483
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• 2006

In this study, as a part of research which is to make 50kg NSI turnout of PC sleeper, the main objective of this study is the optimization of PC sleeper's section, the number of PS tension wire. For this purpose, the finite element analysis was conducted to evaluate the serviceability and the safety of NSI PC sleeper developed. Analytical results showed that PC sleeper adapted in this study satisfied not only serviceability criterion but also safety criterion.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.515-524
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• 2022

The turnout system of the sleeper floating tracks (STEDEF) on urban transit is a Anti-vibration track composed of a wooden sleeper embedded in a concrete bed and a sleeper resilience pad under the sleeper. Therefore, deterioration and changes in spring stiffness of the sleeper resilience pad could be cause changes in sleeper support conditions. The damage amount of manganese crossings that occurred during the current service period of about 21 years was investigated to be about 17% of the total amount of crossings, and it was analyzed that the damage amount increased after 15 years of use (accumulated passing tonnage of about 550 million tons). In this study, parameter analysis (wheel position, sleeper support condition, and dynamic wheel load) was performed using a three-dimensional numerical model that simulated real manganese crossing and wheel profile, to analyze the damage type and cause of manganese crossing that occurred in the actual field. As a result of this study, when the voided sleeper occurred in the sleeper around the nose, the stress generated in the crossing nose exceeded the yield strength according to the dynamic wheel load considering the design track impact factor. In addition, the analysis results were evaluated to be in good agreement with the location of damage that occurred in the actual field. Therefore, in order to minimize the damage of the manganese crossing, it is necessary to keep the sleeper support condition around the nose part constant. In addition, by considering the uniformity of the boundary conditions under the sleepers, it was analyzed that it would be advantageous to to replace the sleeper resilience pad together when replacing the damaged manganese crossing.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.35 no.2
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• pp.131-140
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• 2022

Installing Continuous Welded Rail (CWR) is one of the economical ways to resolve the challenges of noise, vibration, and the open-deck steel railway bridge impact, and the SSF method using the interlocking sleeper fastener has recently been developed. In this study, the method employed for determining the optimum vertical stiffness of the sleeper pad installed under the bridge sleeper, which is utilized to adjust the rail height and absorb shock when the train passes when the interlocking sleeper fastener is applied, is presented. To determine the optimal vertical stiffness of the sleeper pad, related existing design codes are reviewed, and, running safety, ride comfort, track safety, and bridge vibration according to the change in the vertical stiffness of the sleeper pad are estimated via flexible multi-body dynamic analysis,. The flexible multi-body dynamic analysis is performed using commercial programs ABAQUS and VI-Rail. The numerical analysis is conducted using the bridge model for a 30m-long plate girder bridge, and the response is calculated when passing ITX Saemaeul and KTX vehicles and freight wagon when the vertical stiffness of the sleeper pad is altered from 7.5 kN/mm to 240 kN/mm. The optimum stiffness of the sleeper pad is calculated as 200 kN/mm under the conditions of the track components applied to the numerical analysis.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.6
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• pp.569-577
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• 2012

In this study, a theoretical investigation of optimized sleeper spacing which can suppress resonances of a railway track is attempted. To achieve this, we introduced a minimization problem in which the objective function is given by the wave transmittance and the design variable is defined by sleeper distribution. In the analysis the rail is modeled by a Timoshenko beam and the sleeper is represented by a mass. The infinite track analysis is realized by attaching the transmitting boundaries at both ends of the finite optimization region. Through numerical analyses the sleeper spacing effective in reduction of the transmittance is discussed. Furthermore, the feasibility of the proposed method is validated in the aspect of vibration reduction through response analyses for a harmonic load.

• The Journal of the Convergence on Culture Technology
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• v.8 no.6
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• pp.667-674
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• 2022

In this study, the correlation between the damage type and operating conditions of the sleepers was analyzed based on the design data and visual inspection results for the concrete sleepers of the sleeper floating track (STEDEF) that have been in operation for more than 20 years. It appeared in the form of cracks, breakages, and breaks in the concrete at the center and tie bar contact and buried areas. As a result of the numerical analysis, it was analyzed that the change in the left and right spring stiffness of the sleeper resilience pad increases the maximum stress, tensile stress, compressive stress, and displacement of the concrete sleeper, and stress concentration in the concrete at the tie bar contact area. It was proved analytically that the sleeper resilience pad can affect the damage of the concrete sleeper. Therefore, damage of concrete sleepers in the sleeper floating track in urban transit could be caused by changes in spring stiffness of sleeper resilience pads. It was reviewed that preventive maintenance such as improvement and timely replacement of sleeper resilience pads was necessary.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.1129-1137
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• 2007

50kg NSI PCT(Prestress Concrete Timber, sleeper) is developed for the purpose of low maintenance cost, Extend life cycle, Track stability, Friendly Environment, Good running quality. In this study, as a part of research which is to make renovated NSI turnout, the main objective of this study is the optimization of PC sleeper's section, the number of PS tension wire. For this purpose, the finite element analysis was conducted to evaluate the serviceability and the safety of NSI PC sleeper developed.

• Journal of the Korean Society for Advanced Composite Structures
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• v.6 no.1
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• pp.51-58
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• 2015

Global buckling is a bending of pipeline and it occurs when the stability of pipeline is distributed by excessive axial force. Subesea pipeline is subjected to axial force induced by temperature and pressure from well and resulting phenomena should be controlled in appropriate manner. Global buckling of subsea pipeline is still ongoing research subject and is studied various organization. In this study, various control methods such as buoyancy module, sleeper, and snake lay for global buckling of subsea pipeline were numerically investigated with various design parameters. From the numerical simulation results, the global buckling control method using sleepers shows better results than buoyancy module and snake lay control methods in the sense of combined stress after buckling. Furthermore, the global buckling of full scale pipeline of 80km with uneven seabed profile were successfully managed when the sleeper was installed.