• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.36 no.1
• /
• pp.39-48
• /
• 2023

Because a railway bridge is designed over a long period of time and covers a large site, it involves various environmental factors and uncertainties. For this reason, design changes often occur, even if the design was thoroughly reviewed in the initial design stage. In particular, design changes of large-scale facilities, such as railway bridges, consume significant time and cost, and it is extremely inefficient to repeat all the procedures each time. In this study, a technique that can improve the efficiency of learning after design change was developed by utilizing the learning result before design change through transfer learning among deep-learning algorithms. For analysis, scenarios were created, and a database was built using a previously developed railway bridge deep-learning-based prediction system. The proposed method results in similar accuracy when learning only 1000 data points in the new domain compared with the 8000 data points used for learning in the old domain before the design change. Moreover, it was confirmed that it has a faster convergence speed.

• Journal of the Korean Society of Safety
• /
• v.31 no.1
• /
• pp.74-80
• /
• 2016

In this paper, structural characteristics for an extradosed prestressed concrete box girder bridge are investigated in terms of selective parameters. These parameters are mainly associated with the structural details of the extradosed bridge and derived from currently available literatures regarding previous design drawings. The analyses have been carried out using general-purpose structural analysis program, RM-Space Frame. The parameters evaluated for the present study represent the most salient features of the extradosed bridge and are as follows; 1) span length ratio(side-span length to center-span length), 2) boundary condition of girder, 3) height of pylon, 4) anchorage location of external cables and 5) girder stiffness. The analytical predictions indicate that span length ratio and pylon height are reasonably adequate in the range of 0.55 to 0.60 and $L_m/8$ to $L_m/12$ respectively for the bridge under consideration. Also, demonstrated is the boundary condition of girder, in which rigid-connection details give more efficiency than the continuous details. In addition, considering structural characteristics of the extradosed bridge, it is desirable that the girder stiffness should be determined by the stress range of external cables rather than bending moment of girder.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2010.10a
• /
• pp.214-215
• /
• 2010

• Proceedings of the KSR Conference
• /
• 2006.05b
• /
• pp.1081-1087
• /
• 2006

• Journal of the Korean association of regional geographers
• /
• v.15 no.1
• /
• pp.67-85
• /
• 2009

The Trans-Central Asian Railway consists of the Trans-Caspian Railroad, the Kazalinsk Route, the Turk-Sib, and the Trans-Kazakhstan Trunk Line. Currently, one-fifth of the residents in Central Asia are living around these railroads on which 70% of the economic activities in the region depends. The construction of the railroads in Central Asia was motivated by the Russian Empire's competition 'with its maritime rival, the United Kingdom, over the Eurasian heartland in a geostrategic sense. Using the railroads, the Russian Empire aspired to connect its central industrial regions in European Russia with the remote frontier areas in the Central Asian republics and to increase economic specialization of the region. After the breakdown of the USSR, however, the rail network, which had well been linked among the regions in the former Soviet nations, has been in a deteriorated linkage with their non-Soviet neighboring nations. Despite a lot of problems to be solved, the Trans-Central Asian rail network is expected to play a crucial role as a land bridge between East Asia and Europe as well as between Russia/the Baltic sea and the Indian Ocean/the Persian Gulf in the long-term.

• Proceedings of the KSR Conference
• /
• 2011.10a
• /
• pp.1583-1593
• /
• 2011

As we see the continuation of the increase in the speed of the High Speed railroad worldwide, there is a concern for a possible problem in the connecting transition zone in the railway infrastructure. Honam High Speed railroad's transition zone in the hub for the rotation structures and other supporting structures such as approach slab, sub slab, approach block, etc. Due to its increase in speed of the design speed, and its important role on the driving stability and credibility of the bearing ground performance, we must seek and fine a prevention plan for a cause of differential settlement, as well as the cause of the derailment. In this dissertation, domestic, as well as international design manuals and the applicability of the control standards are studied. Also through the study target, Honam High Speed railroad zone 4-1, we evaluated the connecting componant of the Yeon-Jeong bridge through the eigenvalue and weight transfer of the train when operated at 300km/h, 350km/h, 400km/h, 450km/h, and were able to achieve detailed assessment by checking track behaviors, looking at various components such as the rotation acceleration according to the inversion of the distance length, displace length, displacement and stress distribution. Through these studied, possibility of operating at 400km/h was evaluated based on the condition of the current design basis.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.27 no.4
• /
• pp.305-312
• /
• 2007

Among many types of light rail transits (LRT), the rubber-tired automated guide-way transit (AGT) is prevalent in many countries due to its advantages such as good acceleration/deceleration performance, high climb capacity, and reduction of noise and vibration. However, AGT is generally powered by high-voltage electric power feeding system and it may cause electromagnetic interference (EMI) to measurement sensors. The fiber optic sensor system is free from EMI and has been successfully applied in many applications of civil engineering. Especially, fiber Bragg grating (FBG) sensors are the most widely used because of their excellent multiplexing capabilities. This paper investigates a prestressed concrete girder bridge in the Korean AGT test track using FBG based sensors to monitor the dynamic response at various vehicle speeds. The serviceability requirements provided in the specification are also compared against the measured results. The results show that the measured data from FBG based sensors are free from EMI though electric sensors are not, especially in the case of electric strain gauge. It is expected that the FBG sensing system can be effectively applied to the LRT railway bridges that suffered from EMI.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2009.10a
• /
• pp.772-778
• /
• 2009

By rising the interests of the railroad, It has been required the research about railroad structure. And since 2000, the study about railway bridges caused by steel box railway bridges has been only 0.2%. So I was hard to find out about steel box railway bridges. In this study, I evaluate and analyze 4 types(KTX, Saemaeul, Mugunghwa, Freight) of dynamic caused by train loading, natural frequency and damping ratio, verticality deflection and verticality acceleration, end slope deflection, impact factor for dynamic characteristics analysis. natural frequency was measured 2.45Hz~3.34Hz and damping ratio revealed for 1.26~2.84%. Maximum verticality deflection(4.86mm) was sufficiently satisfied the design criteria(30.1mm), but in the case of verticality acceleration's respond, design criteria BRDM(Bridge Design Manual) & CTRL presentation derive rail limit value 0.35g be more than value 6 time recorded, maximum was measured 0.49g in 3 kinds of train(KTX, Saemaeul, Mugunghwa), except for Freight. Survey impact factor of Experiment bridge was 0.20 which is measured when the KTX(15:04) was driving. impact factor is enough contended with design criteria 0.29 which is presented in domestic railway design criteria and thoroughly guarantee the dynamic stability.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2001.03a
• /
• pp.231-238
• /
• 2001

To investigate the underground structure of shallow water, Han-river near Yangsou-Ri, high resolution hydroacoustic measurements were carried out for the engineering design of railroad bridge. The acoustic source was a Boomer with an energy of 90 to 280J and in a frequency range up to about 16KHz. The reflected signals were received by using both traditional hydrophones(passive element) and a specially devised receiver unit(active element) mainly composed of piezofilms and preamplifier. They are connected to the "SUMMIT" data acquisition system(DMT-GeoTec company), where the sampling interval was set to 1/32㎳. The source position was continuously monitored by a precision DGPS system whose positioning accuracy was on the order of loom. For the quality control purposes, two different source-receiver geometries were taken. That is to say, the measurements were repeated along the profile everytime depending on the different source energy(175J, 280J), the receiving elements(passive, active) and two different source-receiver geometries. It was shown that the data resolution derived from a proper arrangement with the active hydrophone could be greatly enhanced and hence the corresponding profile section caused by the regular data processing system "FOCUS" accounted excellently for the underground formation below the shallow water.w the shallow water.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.19 no.12
• /
• pp.1306-1314
• /
• 2009

By rising the interests of the railroad, It has been required the research about railroad structure. And since 2000, the study about railway bridges caused by steel box railway bridges has been only 0.2 %. So I was hard to find out about steel box railway bridges. In this study, I evaluate and analyze 4 types(KTX, Saemaeul, Mugunghwa, Freight) of dynamic caused by train loading, natural frequency and damping ratio, verticality deflection and verticality acceleration, end slope deflection, impact factor for dynamic characteristics analysis. natural frequency was measured 2.45 Hz~3.34 Hz and damping ratio revealed for 1.26~2.84 %. Maximum verticality deflection(4.86 mm) was sufficiently satisfied the design criteria(30.1 mm), but in the case of verticality acceleration's respond, design criteria BRDM(bridge design manual) & CTRL presentation derive rail limit value 0.35 g be more than value 6 time recorded, maximum was measured 0.49 g in 3 kinds of train(KTX, Saemaeul, Mugunghwa), except for Freight. Survey impact factor of Experiment bridge was 0.20 which is measured when the KTX(15:04) was driving. impact factor is enough contended with design criteria 0.29 which is presented in domestic railway design criteria and thoroughly guarantee the dynamic stability.