• Title, Summary, Keyword: 이동하중

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A Study on Numerical Analysis of Flexible Pavements under Moving Vehicular Loads (차량의 이동하중을 고려한 연성포장의 수치해석 기법 연구)

  • Park, Seoksoon;Kim, Nakseok
    • Journal of the Society of Disaster Information
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    • v.7 no.3
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    • pp.206-219
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    • 2011
  • The important elements in pavement design criteria are the stress and strain distributions. To obtain reasonable stress and strain distribution, tire contact area and tire pressures are very important. This study presents a viscoelastic characterization of flexible pavement subjected to moving loads. During the test, both longitudinal and lateral strains were measured at the bottom of asphalt layers and in-situ measurements were compared with the results of numerical analysis. A 3-dimension finite element model was used to simulate each test section and a step loading approximation has been adopted to analyze the effect of a moving vehicle on pavement behaviors. For viscoelastic analysis, relaxation moduli, E(t), of asphalt mixtures were obtained from laboratory test. Field responses reveal the strain anisotropy (i.e., discrepancy between longitudinal and lateral strains), and the amplitude of strain normally decreases as the vehicle speed increases. In most cases, lateral strain was smaller than longitudinal strain, and strain reduction was more significant in lateral direction.

회전 핀에 의한 이동 하중에 따른 보의 대변형 수치 해석

  • 정일섭
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.65-65
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    • 2004
  • 스프링은 변위에 상응하는 에너지를 저장하는 기계 요소로서 다양한 분야에 적용되고 있으며, 나선형(helical) 스프링, 와선형(spiral) 스프링, 비틀림 막대, 디스크(disk) 스프링, 판(plate) 스프링, 일정 하중(constant force) 스프링 둥 다양한 종류가 있다. 근래 많이 사용되는 LCD 모니터 가운데 일부는 경사(tilt), 회전(pivot), 방향 전환(swivel) 등 모니터의 각도 변화가 가능하도록 제작되며, 이러한 각도 변화시 사용자가 적절한 반력을 느끼도록 인간 공학적으로 설계되어 있다.(중략)

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Analysis of Probability and Extended Life Cycle of Strengthened Bridge Deck (성능향상된 교량 바닥판의 확률론적 해석 및 수명연장 분석)

  • Sim, Jong-Sung;Oh, Hong-Seob;Choi, Jang-Whan;Kim, Eon-Kyoung
    • Journal of the Korea Concrete Institute
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    • v.15 no.5
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    • pp.635-642
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    • 2003
  • Although the strengthening effect of deteriorated concrete bridge decks has been studied by various authors, most researches are focused on the experimental works on the pulsating loading in laboratory in spite of deterioration of deck caused by moving vehicle loads. In this research, a theoretical live load model that was proposed to reflect an effect of moving vehicle loads is formulated from a statistical approach on the measurement of real traffic loads for various time periodsin Korea. Fatigue life and strengthening effect of strengthened bridge decks strengthened with either Carbon Fiber Sheet or Grid typed Carbon Fiber Polymer Plastic by the probabilistic and the reliability analyses are assessed. As a results, secondary bridge deck (DB18) strengthened with FRP ensures a sufficient fatigue resistance against the increased traffic loads as well as load carrying capacity in life cycle.

Application of Equivalent Walking Loads for Vibration Analysis of Building Floor Subjected to Footstep Loadings (보행하중을 받는 건축물 바닥판의 진동해석을 위한 등가 보행하중의 적용)

  • 김기철;이동근
    • Journal of the Earthquake Engineering Society of Korea
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    • v.5 no.5
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    • pp.35-45
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    • 2001
  • Recently, the floor systems those require large open space may have low inherent damping due to the decline of the use of curtain walls. Furthermore, the use of the high strength materials has resulted in more flexible and longer spanning in floor systems. The long span structures such as shopping malls, offices and large assembly rooms may lead to significant dynamic response due to human activities. Excessive vibrations make the occupants uncomfortable and deteriorate the serviceability of buildings. It is now proved that footfall loading is the major source of floor vibrations. The common method of application of walking loads for the vibration analysis of structures subjected to walking loads is to inflict measured walking loads and periodic function at a node. But this method could not account for the moving effect of walking. In this study, natural frequency and damping ratio of example structure are evaluated by heel drop tests. And the application of equivalent walking loads is used for on efficient vibration analysis of the plate structures subjected to walking loads.

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Nonlinear Dynamic Behavior of Temporary Rail Considering the Effect of Vibration (진동영향을 고려한 가시설 레일의 동적 거동 특성)

  • Lim, Hyung Joon;Ryu, Dong Hyeon;Won, Jong Hwa;Kim, Moon Kyum
    • Journal of The Korean Society of Civil Engineers
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    • v.28 no.2A
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    • pp.171-178
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    • 2008
  • The object of this study is to propose a rate of vibration increase in the analysis of temporary rail non-fixed in the vertical direction and characterize the nonlinear dynamic behavior of temporary rail while considering longitudinal and latitudinal load, vibration and lifting. The rate of vibration increase is proposed through measurement of an actual structure that is largely affected by loading and vibration of the superstructure. Dynamic behavior was additionally characterized by the dynamic response resulting from nonlinear dynamic finite element analysis with vehicle loading, including the rate of vibration increase. As a result, the rate of vibration increase by the vibration of an Auto Bar Machine is determined as 7% and the maximum stress in the analysis of the nonlinear rail is increased 14.5% over that of linear rail, and temporary rail is shown to be very sensitive to the velocity of the superstructure.

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Three Dimensional Model for Dynamic Moving Load Analysis of a PSC-I Girder Railway Bridge (PSC-I 거더 철도교량의 3차원 동적 이동하중 해석 모델)

  • Cho, Jeong-Rae;Kim, Dong-Seok;Kim, Young Jin;Kwark, Jong-Won;Jang, Seung Yup
    • Journal of the Korean Society for Railway
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    • v.16 no.4
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    • pp.286-297
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    • 2013
  • In this paper we evaluated dynamic stability, considering the effects of modeling and analysis methods on moving load analysis, for which a sophisticated 3 dimensional model of a PSC-I type girder bridge was used. For this purpose, we suggested a reasonable modeling method and the physical properties of the concrete and ballasted track system involved. We also analyzed the response characteristics according to: 1) the type of track system; 2) whether or not the track was modeled; 3) whether or not the distance between the girder center and the bearing were considered; 4) the analysis method (i.e., direct integral and modal analysis); 5) whether or not the frequency was filtered.

Study on Dynamic Characteristics of Structure Approaches by Train Moving Loads (열차이동하중 작용시 구조물 접속부의 동적 거동특성 연구)

  • Eum, Ki Young;Kim, Young Ha;Kim, Jae Wang
    • Journal of the Korean Society for Railway
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    • v.16 no.4
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    • pp.298-304
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    • 2013
  • This paper systematically analyzes the dynamic effects of structure approaches which are expected to have direct effects on train loads - according to the train's acceleration as the area under consideration is located in a section where acceleration of high speed railway vehicles and the train's operating speed happens. In addition, through an examination of the dynamic train loads, dynamic behavioral characteristics of embedded structures and structure approaches were analyzed and a numerical analysis has been carried out in order to evaluate the performance of track subgrade and the safety of the structure. As a result, we reach the conclusion that the dynamic effects by train loads is low, but somewhat high vertical acceleration occurs.