• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1040-1045
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• 2004

A study has been performed to investigate on the dynamic behavior of bridges crossed by the KTX(Korea Train eXpress). The investigated bridge is a 2-span continuous concrete box bridge with spans of 40m length named Yeon-Jae bridge. We have performed many field tests on the dynamic behaviors of a real bridge for KTX using various sensors. For this study, various sensors have been installed on the Yeon-Jae bridge located in the experimental section of the KHSR(Korea High-Speed Railway) track and tests have been performed. Through this study, it is known that effects of local modes and sleepers in the box-girder bridge for the KTX on the dynamic responses is remarkable. Therefore, in the investigation on the accelerations of the box-girder bridge, three dimensional model should be adopted in numerical analysis including the effects of sleepers. The effect of temperature on the accelerations of the bridge should be investigated in the further studies to determine the reason of excessive acceleration.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.444-451
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• 2003

In this study, a new three-dimensional finite element analysis model of high-speed railway bridges considering train-bridge interaction, in which various improved finite elements are used for modeling structural members, is proposed. The box-type bridge deck of a railway bridge is modeled by the NFS(Nonconforming Flat Shell) elements with 6 degrees of freedom. Track structures are idealized using the beam finite elements with the offset of beam nodes and those on Winkler foundation with two parameters. And, the vehicle model devised for a high-speed train is employed, which has an articulated bogie system. By Lagrange's equations of motion, the equations of motion of a bridge-train system can be formulated. Finally, by deriving the equations of the forces acting on a bridge considering bridge-train interaction the complete system matrices of total bridge-train system can be constructed. As numerical examples of this study, 2-span PC box-girder bridge is analyzed and results are compared with experimental results.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2005년도 추계학술대회 논문집
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• pp.1177-1183
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• 2005

This paper presents the effects of dynamic response of the railway bridge through the suspension system when the train is moving with uniform speed and non-uniform speed Railway bridges are subjected to dynamic loads generated by the interaction between moving vehicles and the bridge structures. these dynamic loads result in response fluctuation in bridge members. To investigate the real dynamic behavior of the bridge, a number of analytical and experimental investigation should be carried out. This paper, a train/bridge interaction analysis program considerate braking action. New scheme consideration of braking action on the bridge using speed-dependent braking function is presented. This program also used torsional degree of freedom and constraint equation based on geometrical relationship in order to take into consideration three-dimensional eccentricity effect due to the operation on double track through quasi three-dimensional analysis.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 추계학술대회 논문집
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• pp.17-23
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• 1998

The objective of this study is to investigate the dynamic behaviors of KHSR(Korea High-Speed Railway) bridge supported by elastomeric bearings subjected to high-speed vehicles. The effects of damping on the dynamic behaviors are also studied. The train composed of two power cars, two motor cars and eighteen passenger cars are simulated using constant moving forces for simplicity and effectiveness in the analysis. Direct integration method are used to solve the dynamic equation of motion. The bridge analyzed is real bridge with 2@40m span and concrete continuos box girder. The bridge is model led using frame element in three dimensional space. From the results of this study, the effects of elastomeric bearing on the dynamic responses of bridge(especially vertical accelerations) may cause undesirable behaviors. Damping are very important in the dynamic behaviors of the bridge subjected to high-speed railways. And so, dynamic analysis of steel bridge for high-speed railway supported by elastomeric bearings should be performed carefully.

• Earthquakes and Structures
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• 제16권4호
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• pp.391-399
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• 2019

Residual deformation of high-speed railway bridge piers is cumulative under repeated earthquakes, and influences the safety and ride comfort of high-speed trains. This paper investigates the effects of the peak ground acceleration, longitudinal reinforcement ratio, and axial compression ratio on the cumulative deformation through finite element analysis. A simply-supported beam bridge pier model is established using nonlinear beam-column elements in OpenSees, and validated against a shaking table test. Repeated earthquakes were input in the model. The results show that the cumulative deformation of the bridge piers under repeated earthquakes increases with the peak ground acceleration and the axial compression ratio, and decreases with the longitudinal reinforcement ratio.

• Structural Engineering and Mechanics
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• 제54권5호
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• pp.1017-1044
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• 2015

This study aimed to investigate the random vibration characteristic of train-slab track-bridge interaction system subjected to both track irregularities and earthquakes by use of pseudo-excitation method (PEM). Each vehicle subsystem was modeled by multibody dynamics. A three-dimensional rail-slab- girder-pier finite element model was created to simulate slab track and bridge subsystem. The equations of motion for the entire system were established based on the constraint condition of no jump between wheel and rail. The random load vectors of equations of motion were formulated by transforming track irregularities and seismic accelerations into a series of deterministic pseudo-excitations according to their respective power spectral density (PSD) functions by means of PEM. The time-dependent PSDs of random vibration responses of the system were obtained by step-by-step integration method, and the corresponding extreme values were estimated based on the first-passage failure criterion. As a case study, an ICE3 high-speed train passing a fifteen-span simply supported girder bridge simultaneously excited by track irregularities and earthquakes is presented. The evaluated extreme values and the PSD characteristic of the random vibration responses of bridge and train are analyzed, and the influences of train speed and track irregularities (without earthquakes) on the random vibration characteristic of bridge and train are discussed.

• Structural Engineering and Mechanics
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• 제64권1호
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• pp.45-58
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• 2017

This paper presents the application of topology optimization as a design tool for a steel railway bridge. The choice of a steel railway bridge is dictated by the particular situation that it is suitable for topology optimization design. On the one hand, the current manufacturing techniques for steel structures (additive manufacturing techniques not included) are highly appropriate for material optimization and weight reduction to improve the overall structural efficiency, improve production efficiency, and reduce costs. On the other hand, the design of a railway bridge, especially at higher speeds, is dominated by minimizing the deformations, this being the basic principle of compliance optimization. However, a classical strategy of topology optimization considers typically only one or a very limited number of load cases, while the design of a steel railway bridge is characterized by relatively concentrated convoy loads, which may be present or absent at any location of the structure. The paper demonstrates the applicability of considering multiple load configurations during topology optimization and proves that a different and better optimal layout is obtained than the one from the classical strategy.

• 한국철도학회논문집
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• 제1권1호
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• pp.30-39
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• 1998

The functions of diaphragms at abutments and piers of PSC box girder railway bridge are to transfer forces from the superstructure onto bearings or columns and to stiffen the superstructure cross-section against in -plane deformation. Due to stress disturbance at diaphragm, the design for the diaphragm using conventional design method is relatively irrational than those for other structural members. And, due to contribution to boundary condition of deck slab by the diaphragm, the behavior of deck slab near the diaphragm is different from that of the deck slab obtained from two dimensional analysis of the bridge, which is basis for the design of deck slab. In this paper, three dimensional behavior of deck slab near the diaphragm of prestressed concrete (PSC) box girder railway bridge constructed by the precast span method are analyzed by using three dimensional finite element modeling and using the strut-and-tie model design of the diaphragm are presented. The modeling techniques used in this paper can be applied effectively to examine the causes of cracks at deck slab near diaphragm and to design diaphragm rationally.

• 한국음향학회지
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• 제34권1호
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• pp.52-59
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• 2015

국내 철도의 환경 소음 예측을 위해서 기존에는 총합 소음도의 거리별 경험식에 기초한 모델을 이용하였던 바, 교량 주변 소음도를 계산하는 데에도 거리만의 함수를 이용하였다. 그러나 콘크리트교에서는 수음점의 거리뿐만 아니라 위치에 따라서도 소음도가 변화한다. 본 논문에서는 철도 콘크리트교에서 교량 상판에 의한 회절 및 지면 효과를 고려한 소음전파 예측모델을 도출하였으며, 이때 ISO 9613-2의 소음 전파 모델을 이용하였다. 고속철도 콘크리트 교 주변 소음도에 대한 예측값을 실제 측정결과와 비교하였으며, 그 결과 본 예측 모델이 비교적 작은 오차를 냄을 확인하였다.

• 한국철도학회논문집
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• 제8권3호
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• pp.267-275
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• 2005

Prestressed concrete girder(PSC girder) bridges have been used widely at the railway as well as highway because they are great in the functional and economical efficiency. Also they have the advantage of convenience of design and construction. However it could be easily verified that the section of PSC girder is excessive design, which has much redundancy against design loads. Thus, in this paper the formulation of the optimum design for PSC girder railway bridge is suggested and dominant design variables and constraints are inquired as performing the optimum design. In order to effective optimum design, design variables are formulated as PSC girder sectional dimension and girder space. The objective is adopted as total cost of PSC girder railway bridge. Also, constraints are formulated according to Korean railway design specification and considering construction-ability such as PS anchorage and girder space. Using the proposed optimum design system, optimum PSC girder railway bridge design has been performed. And from the results of analysis it is suggested to denote the optimum section which satisfies the structural safety and economical efficiency all together.