• Title, Summary, Keyword: Moving wheel loading

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A Comparative of Ground Stress with Difference of the Fixed Point Loading and Moving Wheel Loading (모형실험을 통한 고정 및 이동하중 재하 방법에 따른 노반 변형거동 비교)

  • Choi, Chan-Yong;Shin, Eun-Chul;Eum, Ki-Young;Shin, Min-Ho
    • Journal of the Korean Society for Railway
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    • v.14 no.1
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    • pp.49-56
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    • 2011
  • In this paper, it was compared the characteristics of the stress and settlement that occur from a track on the ground using a model test and has quantitatively analyzed the difference based on stress path and effect of the rotation of principal stress. Under identical roadbed conditions, the settlement generated by moving wheel loads were found to be 6 times and 3 times larger than that from static loads and cyclic loads, respectively. The deviator stress affecting shear deformation and the length of stress path generated by moving loads were twofold or greater increase than those by static loads. Furthermore, the stress path generated by moving loads was approached more closely to Mohr-Coulomb failure criteria compared to that by static loads. Also, it was found that ballasted track was occurred about 60% of maximum stress at $40^{\circ}$ of the rotation angle of principal stress and was affected with rotation of principal stress with moving wheel loading condition.

Behavioral Characteristics of Precast Concrete Slab using Wheel Load Tester (윤하중 시험 차량을 활용한 프리캐스트 콘크리트 바닥판의 거동 특성)

  • Park, Seok-Soon;Kim, Nak-Seok
    • Journal of Korean Society of Hazard Mitigation
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    • v.10 no.1
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    • pp.29-34
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    • 2010
  • The main objective of this research is to present the behaviors of precast concrete slab under moving wheel loads. The simulated moving wheel tester and precast concrete slab were designed for this research. In particular, a comparative analysis between the structural analysis and the moving wheel load test was evaluated in connection parts, deformation, bedding layer of concrete slab panels. In the comparisons of the test results from static and moving wheel loads, the maximum deformations were similar. It should be noted that the deformation of panel 2 from the static loading test was larger than that of other panels, while the deformations of panels 1 and 3 were more noticeable than that of panel 2.

Fatigue Strength of PSC Deck Slabs under Moving Wheel Load (윤하중 이동 효과를 고려한 장지간 PSC 바닥판의 피로 성능)

  • Joh, Chang-Bin;Yoon, Hye-Jin
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.94-97
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    • 2006
  • This paper reports fatigue test results of 1/3 scaled PSC slab models using moving wheel loading machine. The purpose of the test is to improve the fatigue formulas by comparing the existing formulas with the test results. Based on the result, improved fatigue formula is proposed for the PSC slab.

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Experimental Study of Stiffness transition zone by using Moving Wheel Loads (이동하중에 의한 지지강성 변화구간에 대한 실험적 연구)

  • Lee, Jin-Wook;Choi, Chan-Yong;Lee, Seong-Hyeok;Park, Tae-Hwan
    • Proceedings of the KSR Conference
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    • pp.1056-1061
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    • 2007
  • Railroad roadbed was consisted into structure types that earthwork, tunnel, bridge and joint sections. Joint section was affected a large factor confidence and safety of the train running by stiffness transition zone that track substructure stiffness change section as like between tunnel and earthwork from ballast track to concrete track. These problems are the results of increased dynamic wheel loads, which also lead to wear and tear on vehicle components and contribute to poor ride quality. The study presented in this paper was conducted on model test by using Wheel Moving Loading System.

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Evaluation of Deformation Characteristics for Bridge/Earthwork Transition Reinforcement Methods Considering Moving Load (이동하중을 고려한 교량/토공 접속부 보강방안별 변형특성 평가)

  • Lee, Il-Wha;Lee, Sung-Jin;Lee, Su-Hyung;Kang, Tae-Ho
    • Journal of the Korean Society for Railway
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    • v.13 no.3
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    • pp.298-303
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    • 2010
  • The transition zone of the railway is the section which roadbed stiffness is suddenly varied like as tunnel-earthwork, bridge-earthwork and concrete track-ballasted track. There are about 450 tunnel-bridge transition sections on Kyungbu high-speed railway line. It is very important to pay careful attention to construction of these transition zones, in order to secure the train running safety. So, we developed a finite element model of the moving wheel loading to simulate the behavior of bridge-earthwork transitions in this paper. The most distinctive characteristics of the model proposed is to simulate the real wheel behavior on rail. And the main analysis object is to evaluate and compare the deformation characteristics of the transition zone according to the reinforcement methods and length of transition zone which is adopted to high-speed railway. Based on the analysis results, we assessed the effect of the reinforcements on the transition zone of high-speed railway.

Behaviors of Settlement for Transitional zone with Moving Wheel Loading (이동하중을 고려한 토공-접속구간 침하거동)

  • Choi, Chan-Yong;Lee, Jin-Wook
    • Proceedings of the KSR Conference
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    • pp.238-242
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    • 2008
  • Transitional zones, one of the typical weak area of earthworks, require lasting a maintenance work due to a differential stiffness of substructures. It is very difficult problem that transition zone was perfectively prevented against a differential settlement. The transitional zone will deteriorate at an accelerate rate. This may lead to pumping ballast, swinging or hanging sleepers, permanent rail deformations, worn track components, and loss of surface and gauge. In this study, it is performed that settlement behavior in transitional zone was compared with small model test.

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Field Evaluation of Traffic Wandering Effect on Asphalt Pavement Responses (차량의 횡방향 주행이격에 의한 아스팔트 콘크리트 포장의 응답특성 분석)

  • Seo, Youngguk;Kwon, Soon-Min;Lee, Jae-Hoon
    • Journal of The Korean Society of Civil Engineers
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    • v.26 no.3D
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    • pp.453-459
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    • 2006
  • This paper presents an experimental evaluation of wandering effect on asphalt concrete pavement responses. A laser-based wandering system has been developed and its performance is verified under various field conditions. The portable wandering system composed of two laser sensors with Position Sensitive Devices can allow one to measure the distance between laser sensors and tire edges of moving vehicle. Therefore, lateral position of each wheel on the pavement can be determined in a real time manner. Pavement responses due to different loading paths are investigated using a roll over test which is carried out on one of asphalt surfaced pavements in the Korea Highway Corporation test road. The pavement section (A5) consists of 5 cm thick surface course; 7 cm intermediate course; and 18 mm base course, and is heavily instrumented with strain gauges, vertical soil pressure cells and thermo-couples. From the center of wheel paths, seven equally-spaced lateral loading paths are carefully selected over an 140 cm wandering zone. Test results show that lateral horizontal strains in both surface and intermediate courses are mostly compressive right under the loading path and tensile strains start to develop as the loading offset becomes 40 cm from the wheel path. The development of the vertical stresses in the top layers of subbase and anti-frost is found to be minimal once the loading offset becomes 50 cm.

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Validation of Permanent Deformation Model for Flexible Pavement using Accelerated Pavement Testing (포장가속시험을 이용한 소성변형예측 모델의 검증)

  • Choi, Jeong Hoon;Seo, Youngguk;Suh, Young Chan
    • Journal of The Korean Society of Civil Engineers
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    • v.29 no.4D
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    • pp.491-497
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    • 2009
  • This paper presents the results of accelerated pavement tests (APT) that simulate permanent deformation (rutting) of asphalt concrete pavements under different temperatures and loading courses. Also, finite element (FE) analysis has been conducted to predict the test results. Test section for APT is the same as one of test sections at Korea Expressway Corporation test road and is subjected to a constant moving dual tire wheel load of APT at three different temperatures: 30, 40, $50^{\circ}C$. The moving wheel is applied at different loading courses within a 75cm wide wheel path to account for traffic wandering. Also, the effect of wandering on permanent deformation development is investigated numerically with three wandering schemes. In this study, ABAQUS is adopted to model APT pavement section with plain stain elements and creep strain rate model is used to take into account viscoplastic stain of asphalt concrete mixtures, and elastic layer properties are back-calculated from FWD measurements. Plus, the effect of boundary condition and subgrade on FE permanent deformation predictions is investigated. A full FE model that accounted for subgrade provided more realistic rut depth predictions, indicating subgrade has contributed to surface rutting.

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Dynamic Characteristics of Railway Structures under High-Speed Train Loading (고속열차 주행 시 동적하중을 받는 철도구조물의 진동 특성)

  • Rhee, Inkyu;Kim, Jae Min
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.33 no.2
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    • pp.121-128
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    • 2020
  • The purpose of this study is to investigate the distribution patterns of displacement and acceleration fields in a nonlinear soil ground based on the interaction of high-speed train, wheel, rail, and ground. For this purpose, a high-speed train in motion was modeled as the actual wheel, and the vertical contact of wheel and rail and the lateral contact, caused by meandering motion, were simulated; this simulation was based on the moving mass analysis. The soil ground part was given the nonlinear behavior of the upper ground part by using the modified the Drucker-Prager model, and the changes in displacement and acceleration were compared with the behavior of the elastic and inelastic grounds. Using this analysis, the displacement and acceleration ranges close to the actual ground behavior were addressed. Additionally, the von-Mises stress and equivalent plastic strain at the ground were examined. Further, the equivalent plastic and total volumetric strains at each failure surface were examined. The variation in stresses, such as vertical stress, transverse pressure, and longitudinal restraint pressure of wheel-rail contact, with the time history was investigated using moving mass. In the case of nonlinear ground model, the displacement difference obtained based on the train travel is not large when compared to that of the elastic ground model, while the acceleration is caused to generate a large decrease.

Soil and Slab Track Interaction (지반과 슬래브궤도의 상호작용)

  • Kang, Bo-Soon;Hwang, Seong-Chun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.334-339
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    • 2002
  • In this report, numerical investigations have demonstrated, that the displacement underneath a moving loading reach a maximum value, if the speed of the load is equal to propagation velocity of the maximum wave. The load speed for which the maximum displacement occurs is called critical speed. The critical speed divides the velocities in a subcritical and a super-critical region. By means of calculations the dynamic behaviour of the slab track-soil is investigated. For concrete slab track dynamic wheel load are given in dependence of relevant excitation mechanismen and speed of the train. These loads can be used for the dimensioning of the track as well as for prognosis of the vibrations at the track and the surrounding soil.

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