• Proceedings of the KSR Conference
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• 2011.05a
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• pp.725-732
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• 2011

The vibration resulting from railway operation is transmitted through the tunnel to adjacent buildings and the transmitted vibration radiates structure-borne noise which is causing a lot of public complaints by its negative effects to the buildings near tunnel. This study performed the parametric study about sleeper space and track support stiffness in order to reduce vibration on the concrete track and near structures. In this study, it was compared and performed vibration analysis and field test about these. In addition, as changing the sleeper space and track support stiffness, vibration of the structures was evaluated. Via this study, in terms of reducing the figure of the sleeper space and track support stiffness to the half, as vibrating acceleration transmitted through concrete round is getting reduced, it transmitted through the tunnel was analysed to the same phenomena. In conclusion, suggested track structure into this study, it can be applied to the track structure of existing line, and it is expected to be a new effective anti-vibration method to prevent public complaints.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.436-442
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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. And also the excessive displacement of the rail may induce decrease ride comfort. Therefore, in order to prevent such problems, the allowable maximum sleeper spacing at a bridge expansion joint was mutually determined. And, the determination procedure of the maximum bridge expansion length based on the allowable sleeper spacing was suggested.

• The Journal of the Convergence on Culture Technology
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• v.10 no.3
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• pp.833-838
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• 2024

The urban railway sleeper floating track(STEDEF) is a structure that structurally separates the sleepers and the concrete bed using sleeper boots and resilience pads to reduce vibration transmitted to the concrete bed. Recently, the resilience pads of sleeper floating tracks that have been in use for more than 20 years are deteriorating. Accordingly, in order to evaluate the performance of the resilience pad, a static spring stiffness test is being performed after extracting the resilience pad. This evaluation technique is performed after replacing the resilience pad in use. However, the track natural frequency can change depending on the resilience pad spring stiffness and the uplift and subsidence of the concrete bed. In this study, modal testing technique was used to evaluate the track natural frequency. For this purpose, the sleeper boots material, resilience pad spring stiffness, and track natural frequency according to concrete bed uplift and subsidence were measured using modal tests at a laboratory scale. It was analyzed that the natural frequency of the sleeper floating track was directly affected by changes in the spring stiffness of the resilience pad. In addition, the change in natural frequency due to the uplift and subsidence of the concrete bed was also found to be large. Therefore, it is believed that the modal test technique presented in this study can be used to evaluate the resilience pad deterioration and voided sleepers.

• The Journal of the Convergence on Culture Technology
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• v.7 no.3
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• pp.517-522
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• 2021

In this study, the causes of damage to the concrete sleepers in a ballast track with under sleeper pads attached to the base of the sleepers installed in the sharp curved track(R=180m) of the urban railway bridge were analyzed. The damage types of concrete sleepers were investigated, and the correlation with track irregularity was reviewed. Also, stress generated in the concrete sleeper was reviewed through structural analysis. As a result, most of the cracks of the sleepers occurred in the section with severe track irregularity. In addition, as a result of the analysis, the stress generated in the track components and the sleepers was found to be reduce in the fastening system using the 4-anchor.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.702-709
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• 2018

A quick-hardened concrete track was developed to improve the aged ballasted track to a concrete track, and applied to earthworks and tunnels of main and urban railways. Rebars for reinforcement are not generally applied to prestressed concrete sleepers. On the other hand, many cracked sleepers have been observed in railroad sites. A wide sleeper, which is one of the main components of quick-hardened concrete track, should be structurally safe and crack-resistant in a ballasted and concrete track to avoid this problem. In particular, a wide sleeper manufactured by a post-tension method must have reinforcing bars applied to the rail-seat section. In this paper, static tests, dynamic tests, and fatigue tests were carried out to compare the flexural strength and crack resistance performance of a wide sleeper with and without reinforcing bars for a quick-hardened concrete track. As a result of the test, if some reinforcing bars are applied appropriately to the rail-seat section of a wide sleeper, it will be possible to prevent the occurrence of cracks, delay the expansion of the crack width, and the flexural fracture.

• The Journal of the Convergence on Culture Technology
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• v.10 no.3
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• pp.839-844
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• 2024

This study analytically analyzed the impact of underground structure displacement behavior on track damage due to adjacent excavation work, ground deterioration, and changes in groundwater level. The concrete track that was the subject of the study was analyzed for sleeper floating track(STEDEF) and precast concrete slab track(B2S). Sleeper floating track is a track structure in which the concrete bed and sleepers are voided. precast concrete slab track is a track structure that induces the elastic behavior of the rail by assembling rails and fasteners using slabs. For numerical analysis, each concrete track, from rail to concrete bed, was modeled as three-dimensional elements. In addition, the displacement behavior of the underground structure was set as a variable to analyze the damage effect on the concrete bed. Using numerical analysis, the concrete bed stress due to uplift and subsidence was analyzed, and the level of crack effect was analyzed by comparing it to the tensile strength and shear strength. As a result of the analysis, it was found that the sleeper floating track was more vulnerable than the precast concrete slab track when the same uplift and subsidence occurred. In addition, uplift and subsidence, it was analyzed that the cracks range in the sleeper floating track was large.

• Proceedings of the KSR Conference
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• 2001.05a
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• pp.369-374
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• 2001

It was estimated that the anti-vibration measures at the source location of railroad are the most active and effective ones. Among CWR(Continuously Welded Rail), elastic rail fastener, floating slab, ballast mat, under sleeper pad, etc. like these various kinds of measures in the source, under sleeper pad as an anti-vibration measure was constructed at the railroad track supporting structures in the Jeon-la Line. In this study, through the field measurement of vibration at the railroad track supporting structures and nearby the ground, the vibration reduction effect of under sleeper pad were evaluated by insertion loss. As a result, vibration reduction effects were 5.0∼12.5㏈ on the concrete slab of the bridge, 3.9∼7.5㏈ on the ground nearby the bridge respectively.

• Journal of the Korean Society for Railway
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• v.20 no.3
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• pp.374-381
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• 2017

Concrete sleepers, installed on majority of railroad track in this nation can, if not maintained properly, threaten the safety of running trains. In this paper, an algorithm for automatically identifying cracks in a sleeper image, taken by high-resolution camera, is developed based on Adaboost, known as the strongest adaptive algorithm and most actively utilized algorithm of current days. The developed algorithm is trained using crack characteristics drawn from the analysis results of crack and non-crack images of field-installed sleepers. The applicability of the developed algorithm is verified using 48 images utilized in the training process and 11 images not used in the process. The verification results show that cracks in all the sleeper images can be successfully identified with an identification rate greater than 90%, and that the developed automatic crack identification algorithm therefore has sufficient applicability.

• 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.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1223-1228
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• 2007

Since KHSL 2nd phase was adapted as a main track design, the interests of concrete slab track system have been gradually increased in the division of rail track engineering and many engineering companies have been trying to adapt a concrete slab track system at this moment. Advantages of this system proved in advanced country, japan and Germany etc. are excellent maintenance, track stability and increasing of buckling resistance This developed turnout is same with the KHSR 1st phase's design and applications rules, components and signaling system since it observes KTX specification. Comparing it with the former turnout, High-elasticity pad, lubrication-free roller slide plate and Rheda2000 PC sleeper are only different. The purpose of this study is the development of high speed turnout on concrete slab track and its application on site. Now these studies are going to show the verification and confidence about the interface between ballast-track and concrete slab track by finding and solving the possible problems when it is installed on site and to make these turnouts applied perfectly and completely on concrete slab track. Its first trial construction in korea had been successfully completed at Sangju-station on July 20th ,2007 thanks to KORAIL and KR. Hereunder Sampyo E&C trys to introduce all of turnout technologies on concrete slab track system with Rheda 2000 sleeper