• Journal of the Korea institute for structural maintenance and inspection
• /
• v.14 no.5
• /
• pp.93-101
• /
• 2010

The effects of braking of trains and roughness of rails on the dynamic behavior of bridges are studied. The train-bridge interaction is considered by solving Lagrange's equation of motions. Newmark's direct integration is used to solve the governing equations. Dynamic train loads acting on piers at each time step are evaluated, and the wheel-rail roughness effect is considered by using the PSD curve of the rail. The model of braking forces in bridge section is based on the change of deceleration mentioned in ASTM(American Society for Testing and Materials) E503-82. Only skidding frictions without considering rolling frictions are modeled, and the friction coefficient of 0.25 is assumed. Parametric studies in a simply supported PC Box girder bridge are carried out to verify the present method and to analyze the effects of train speed, wheel-rail roughness, braking forces on dynamic train loads.

• Computational Structural Engineering
• /
• v.9 no.3
• /
• pp.54-59
• /
• 1996

시속 300km로 주행하는 고속철도 열차의 주행안정성 및 승차감을 확보하기 위해서는 열차하중을 고려한 정교한 정적, 동적해석 및 설계가 이루어져야 한다. 따라서 차량과 궤도의 동적상호작용 및 차량과 교량의 동적상호작용, 터널의 미기압 및 공기압, 대단면 터널굴착의 안정성평가, 열차주행에 의한 지반진동의 예측 등에 전산수치해석기법의 활용 및 개발이 현재 활발히 이루어지고 있다. 그러나 고속철도 보유국을 포함한 선진국들에 비하면은 이러한 전산수치해석분야에 있어서 아직도 더 많은 연구 및 개발이 본 공단을 포함하여 학계 및 연구소에서 이루어져야 하겠으며, 본 경부고속철도 건설사업으로 인하여 차량, 전기시설분야의 각종 첨단기술개발 및 발전과 더불어 하부 토목구조물의 건설 및 설계 해석분야에 많은 발전이 기대된다 하겠다.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.31 no.1
• /
• pp.53-61
• /
• 2018

Ballast track requires constant maintenance work due to progress of track irregularity. Fast Hardening Track(FHT) has been developed to reduce the maintenance effort done by injecting fast hardening mortar in aged ballast to convert slab track. For the application of FHT to a railway bridge, post-installed anchors should be placed at center of the track segment to fix it on bridge. This paper presents track-bridge interaction analysis results with FHT considering stiffness and strength of post-installed anchor, age of FHT concrete and friction between FHT and bridge deck surface. Based on the analysis results, this study suggests when is good to install the anchors and allow normal operation of passing train.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.15 no.3
• /
• pp.1-9
• /
• 2011

The purpose of this study is to examine the dynamic characteristics of low, medium and high speed Maglev trains and guideways through dynamic interaction analysis. The coupled dynamic equations of motion for a vehicle of 10-dof and the associated guideway girders are developed by superposing vibration modes of the girder itself. The controller used in the UTM-01 Maglev vehicle is adopted to control the air gap between the bogie and guideway in this study. The effect of roughness, the guideway deflection-ratio and vehicle speed on the dynamic response of the maglev vehicle and guideway are then investigated using the 4th Runge-Kutta method. From the numerical simulation, it is found that the air gap increases with an increase of vehicle speed and the roughness condition. In particular, the dynamic magnification factor of the guideway girder is small at low and medium speeds, but the factor is noticeable at super-high speeds.

• Journal of the Korean Society for Railway
• /
• v.14 no.6
• /
• pp.545-554
• /
• 2011

In order to get dynamic serviceability of a train travelling on a railway bridge, comfort limits with the deflection of bridge and vertical acceleration on car body are proposed in Eurocode, Shinkansen design criteria, The design guideline of the Honam High-speed railway. The design guideline of the Honam High-speed railway has quoted Eurocode. Therefore it is expected that supplementation of comfort limit of railway bridge according to expansion of span length and the improvement traveling speed of trains in the future would relatively fall behind developed countries in railway. Therefore, in order to secure technological competitiveness in world market, the study was conducted to propose the deflection limit based on vibration serviceability of railway bridges that can consider bridge-train interaction and travelling speed increase. The parameter study and bridge-train dynamic interaction analysis was conducted to figure out the correlation of vertical acceleration on car body and bridge displacement according to the increase in travelling speed. Also, the trend of increasing vertical acceleration on car body according to the increase in travelling speed was confirmed, and the amplification coefficient of vertical acceleration on car body was suggested. And the deflection form and vibration of the bridge were assumed to be in harmonic motion, and transfer function and the amplification coefficient were used to develop the dynamic serviceability deflection limit of the high-speed railway bridge as a formula.

• Journal of the Korean Society for Railway
• /
• v.14 no.1
• /
• pp.39-48
• /
• 2011

The paper describes four practical cases of railway structure concerning a three-dimensional numerical approach to analyse dynamic soil-structure interaction(SSI)of railway tracks on layered soil under transient load in the time domain. The SSI-Model has been implemented in TDAPIII accounting for nonlinear properties of the track and soil. The approach can be also be used to calculate vibration propagation in the soil and its effect on nearby buildings and structure. The Method is applied to analyse the dynamic response of railway tracks due to a moving wheel set. Finally some sample are given in order to reduce the vibration at the point of emission, at the transmission path and the structure itself.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.12 no.4
• /
• pp.629-638
• /
• 1999

본 연구에서는 고속철도에서 차량·교량 구조물의 상호작용을 가능한 정밀하게 취급할 수 있는 3차원 해석모형을 개발하였다. 경부고속철도 교량형식인 PSC 박스거더 교량을 40m 단순 와 25-40-25m 3경간 연속 에 대해 뼈대요소를 사용하여 3차원으로 모형 하였으며, 궤도의 불규칙성은 정상확률과정으로 가정하고, 지수 스펙트럼 밀도함수를 사용하여 궤도의 형상을 생성시켰다. 열차는 경부고속철도 차량 하중효과가 가장 큰 동력차 만을 대상으로 17 자유도 모형과 38 자유도 모형으로 분리하여 개발하였다. 다양한 조건에 대한 분석결과를 검토하면 여러 가지 상황에서 38 자유도 모형의 필수 성이 보여지고 있다. 특히 교량의 솟음 및 장기 처짐에 의한 궤도형상변화가 있는 경우에는 반드시 38 자유도 모형이 적용되어야 하는 것으로 분석되었다. 또한 제동하중이 작용할 때 쏠림 효과에 의한 영향이 큰 것으로 평가되어, 제동에 의한 교량의 동적 거동은 종변 위에 대한 자유 도를 고려할 수 있는 주행차량모형으로 해석되어야 함이 규명되었다.

• Computational Structural Engineering
• /
• v.11 no.3
• /
• pp.253-262
• /
• 1998

본 연구에서는 경부고속철도의 주요 교량형식인 PSC 박스교량을 3차원 뼈대요소를 사용하여 모형화하였으며, 궤도불규칙성의 형상은 지수 스펙트럴 밀도함수를 사용하여 생성시켰다. 경부고속철도차량(K-TGV)중 동력차는 17자유도의 3차원 주행열차로 모형화하였고, 이러한 교량, 궤도불규칙성 및 차량 모형을 이용하여 교량과 차량의 상호작용을 해석할 수 있는 프로그램을 개발하였다. 동적해석을 위한 교량과 차량의 운동방정식은 Lagrange 방정식을 사용하여 유도하였으며, 운동방정식의 수치해석에는 Newmark-β법을 사용하였다. 개발된 프로그램을 이용하여 동력차의 주행에 의한 교량의 시간이력곡선을 구하였으며, 궤도불규칙성의 영향을 분석하였다. 또한 도상의 유무에 따른 교량동적거동의 특성과 함께 열하중의 편심의 영향도 분석하였다.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.24 no.2
• /
• pp.167-175
• /
• 2011

The purpose of this study is to examine the impact that change in speed and modeling methods has on maglevs' runnability. The study constructed equations of motion on 4-DOF, 6DOF, and 10-DOF vehicles respectively and carried out numerical analysis, applying 4th Runge Kutta method, in order to run six different model maglev as changing the vehicles speed on the same bridge that had 2000 to 1 deflection. The analysis revealed that maglev's runnability improved as speed was lower and the specific model had higher number of bogey and EMS.

• Journal of the Korean Society for Railway
• /
• v.18 no.4
• /
• pp.363-373
• /
• 2015

The purpose of this study is to develop a nonlinear algorithm for the dynamic interaction analysis of KTX trains and bridge girders with consideration of separation and flange contact phenomena between wheel and rail. For this, three interaction models between wheel-rail are implemented and compared through numerical examples. That is, the spring model and the non-jump model are briefly explained, and a nonlinear contact model is then proposed to accurately simulate interaction forces of the train-bridge system. Dynamic interaction analysis of a simply supported girder and trains is performed and the analyzed results are presented and compared for the proposed contact model and the other model types. Particularly, flange contact phenomena in the nonlinear contact model are demonstrated under a specific condition.