• 한국소음진동공학회논문집
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• 제19권12호
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• pp.1306-1314
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• 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.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.223-228
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• 2005

Precast concrete deck has many advantages comparing with the in-situ concrete deck, and has been successfully applied to replacement of the deteriorated decks and to the newly constructed highway bridges in domestic region. In order to apply the precast decks into the railway bridges, however, differences of the load characteristics between the highway and the railway should be properly taken into account including the train load, longitudinal force of the continuous welded rail. acceleration or braking force, temperature change and shrinkage. Proper level of the longitudinal prestress of the tendons that can ensure integrity of the transverse joints in the deck system is of a primary importance. To this aim, the longitudinal tensile stresses induced by the design loads are derived using three-dimensional finite element analyses, design codes and theoretical equations for the frequently adopted PSC composite girder railway bridge. The estimated proper prestress level to counteract those tensile stresses is over 2.4 MPa, which is similar to the case of the highway bridges.

• 한국구조물진단유지관리공학회 논문집
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• 제28권2호
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• pp.61-68
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• 2024

국내 경부선 및 호남선의 고속철도교량은 대부분 PSC-box 형식으로 설계되어 있고, 경간장35~40m인 경우 약 4~5Hz 정도의 1차 휨 고유진동수를 가지고 있다. 이때 KTX 고속열차가 290~310 km/h 속도로 주행할 경우, 열차에 의한 가진 진동수가 교량의 1차 휨 고유진동수에 근접하면서 공진 유사 현상이 발생하게 된다. KTX와 함께 향후 운행예정인 EMU-320 고속열차의 증속에 대해서도 철도교량의 동적 응답을 통한 안전성 분석이 필요한 상황이다. 본 연구에서는 실제 철도교량에서 계측된 응답을 기반으로 구조해석모델 개선 기법을 통해 대상 철도교량과 거동이 유사한 해석모델을 구현하였다. 개선된 구조해석모델은 고속철도교량에 KTX가 주행할 때 계측된 응답과 비교하여 검증하고, 이를 통해 KTX와 EMU-320 고속열차가 증속할 경우 동적 응답 특성을 분석하였다. 또한, 결과적으로, 교량 중앙부의 최대 수직변위와 가속도의 변화는 철도설계기준과 비교하여 주행 안전성을 평가하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(II)
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• pp.538-543
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• 2003

This study is the developed prediction of residual effective prestress force of prestressed concrete beam bridges. Developed prediction method is based on the center camber of prestressed concrete beam, structural design. report of various PSC beams, construction reference materials of PSC beams. Evaluation of residual effective prestress force by developed method is compared with evaluation by structural design. This comparison results shows that this developed method is very effective method. Therefore prediction of residual effective prestress force by this developed method will be used for evaluation of the rating of various PSC beam bridges(road bridges and railway bridges).

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 춘계학술대회 논문집
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• pp.706-711
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• 2005

From the using CWR (Continuously Welded Rail) on steel plate girder bridges without ballast, axial forces are occurred from a temperature on CWR and girders. Because of the additional axial forces, studies in order to CWR and developments of devices are proceeding. The track system of steel plate girder bridges is poor. When CWR is used for the system, the resistance on sleepers is increased from a temperature. So it is increasing an effect on CWR and, for solving the effect, longitudinal forces for buckle are being decreased. It is possible that opposite cases can be happened and it is also compared and studied. Therefore, we present a reasonable model for analyzing CWR within the property of steel plate girder railway bridges in Korea. Furthermore, the results analyzed for stability is compared and evaluated with tests. Finally, a reasonable method for the installation of CWR on bridges without ballast is suggested.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.185-190
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• 2005

In order to evaluate that factors such as span length, member type and train loading affected on fatigue of steel railway bridges, in this paper, a series of field tests were carried out for some plate girder bridges. From the result estimated by rainflow counting method to analyze real strain-time curve obtained from the field test, it was known that the fatigue effect is more significant in the bridges having short span length and the secondary members regardless of train load types.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.1223-1228
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• 2005

A lot of PSC railway bridges have been constructed in countries and, they are considered as cost-effective and less maintenance-demanded structures. However, recently several collapse of PSC bridges happened in Europe show that PSC bridges have some serious maintenance problems related to tendon corrosion and wire fractures. Furthermore, any reliable NDT method is not presented until recently. In this paper, AE techniques are investigated for detection of wire fractures in PSC beam. Using long-term monitoring AE techniques, two acoustic signals of wire fractures in a PSC beam are obtained. These data are compared to other noise signals. Based on the test results, the characteristics of the AE signals are classified and wire fracture signals are figured out among the other AE signals. As a result, AE techniques are certainly exposed to tendon fracture sound, and application of AE techniques are better than any other non-destructive method.

• Advances in Computational Design
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• 제2권4호
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• pp.257-271
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• 2017

There are many plain concrete arch bridges in Iran that have been used as railway bridges for more than seventy years. Owe to the fact that these bridges have not been designed seismically, and even may be loaded under high-speed trains, evaluation of fundamental frequencies of the bridges against earthquake and high-speed train vibrations is necessary for considering dynamics effects. To evaluate complex behavior of these bridges, results of field tests are useful. Since it is not possible to perform field tests for all arch bridges, these structures should be simulated correctly by computers for structural assessment. Several parameters are employed to describe the bridges, such as number of spans, length of spans, geometrical and material properties. In this study, results of field tests are used for modal analysis and adapted for 64 three dimensional finite element models with various physical parameters. Computer simulations show length of spans has important effect on fundamental frequencies of plain concrete arch bridge and modal deformations of bridges is in longitudinal and transverse directions. Also, these results demonstrate that fundamental frequencies of bridges decrease after increasing span length and number of spans. Plus, some relations based in the number of spans (n) and span length (l) are proposed for calculation of fundamental frequencies of plain concrete arch bridge.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.3142-3146
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• 2011

This paper introduces improved prestressed concrete (PSC) girders for the railway bridges. In order to improve performance of conventional PSC girders, various types of PSC girders are either under development or have already been applied in railway bridges. Incrementally prestressed concrete girder is one of these newly developed girders. According to the design concept, these types of PSC girders have the advantages of requiring less self-weight while having the capability of longer spans. However, the tensional failure of top flange is one of the critical issues at the first prestressing stage. To effectively provide initial section stiffness of PSC girders, concrete block on the top flange is used in this study. The efficiency of the proposed structures, compared with conventional girders and improved ones, is successfully demonstrated in the example.

• Structural Engineering and Mechanics
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• 제73권2호
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• pp.133-141
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• 2020

This paper presents the applicability of series tuned mass dampers (STMDs) to reduce the multiple resonant responses of continuous railway bridges under high-speed train. The bridge is modeled by two-span Bernoulli-Euler beam with uniform cross-section, and a STMD device consisting of two TMD units installed on the bridge to reduce its multiple resonant vibrations. The system is assumed to be under the action of a high-speed train passage which is modeled as a series of moving forces. Sequential Programming Technique (SQP) is carried out to find the optimal parameters of the STMD that minimizes the maximum peak responses of the bridge. Comparisons with the results available in the literature are presented to demonstrate the effectiveness and robustness of STMD system in reducing the multiple resonant responses of the continuous railway bridges under high-speed trains.