• Title, Summary, Keyword: Axle load

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A Study on the Axle Load Limits of Asphalt Concrete Pavements (아스팔트 콘크리트 포장구조체의 제한교통하중에 관한 연구)

  • Kim, Soo Il;Choi, Jun Sung
    • Journal of The Korean Society of Civil Engineers
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    • v.12 no.2
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    • pp.67-76
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    • 1992
  • A procedure to determine the axle load limits of asphalt concrete pavements are proposed in this study. Axle load limits are determined by calculating maximum tensile strains at the bottom of the asphalt stabilized base layer and maximum vertical strains at the top of the subgrade. In order to investigate the efficiency of axle configuration, calculated influence line of wheel load on domestic expressway pavement system is used. Limiting strains are selected through the analysis of conventional failure criteria. From the analysis of axle load limits about axle composition(single-axle, tandem-axle, tridem-axle), it is found that the axle load limits of tandem-axle and tridem-axle can be calculated by muitipling the axle load limits of single-axle by axle numbers and that axle load limits are closely related to the thickness of each layer of pavement structure. It is also found that the axle load limits by tensile strains are more critical than those by vertical strains on asphalt concrete pavement models of YOUNG-DONG, KYONG-IN and KYONG-BU expressways.

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The Effect of Ground Condition, Tire Inflation Pressure and Axle Load on Steering Torque (노면상태, 타이어 공기압 및 축하중이 조향력에 미치는 영향)

  • Park W. Y.;Kim S. Y.;Lee C. H.;Choi D. M;Lee S. S.;Lee K. S.
    • Journal of Biosystems Engineering
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    • v.29 no.5
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    • pp.419-424
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    • 2004
  • In this study, a series of soil bin experiment was carried out to investigate experimentally the effect of the tire inflation pressure and axle load of tire on the steering torque for the off-road condition. The experiment was performed at the three levels of off-road conditions(ground I, ground II and ground III) and on-road condition(ground IV), four levels of tire inflation pressure(120 kPa, 170 kPa, 220 kPa and 270 kPa), and four levels of axle load(1470N, 1960N, 2450N and 2940N). The results of this study are summarized as follows: 1. Steering torque at the off-road conditions were higher than that on the on-road conditions for all levels of tire inflation pressure and axle load. 2. As the axle load increased, steering torque also increased f3r all experimental ground conditions. 3. For the axle load of 1470N the biggest steering torque was measured on the ground condition I, but as the axle load increased to the value of 2940N the biggest steering torque was measured on the ground condition III. From the above results, it was found that for the low axle load, steering torque gets higher on the soft ground condition, but for the high axle load, steering torque gets higher on hard ground condition for whole range of experimental conditions. 4. As the tire inflation pressure decreased, steering torque increased on the on-road condition, but no specific trend was not found at the off-road conditions.

Estimation of Cumulative Axle-Load Spectrum for Axle-Load Distribution Standard by Vehicle Type (차종별 축하중 분포 정량화를 위한 누적 축하중 스펙트럼 추정연구)

  • An Ji-Hwan;Ohm Byung-Sik;Kim Yeon-Bok
    • International Journal of Highway Engineering
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    • v.8 no.3
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    • pp.29-37
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    • 2006
  • The primary objective of this study is to characterize traffic axle loadings that consider Korea specific traffic conditions for developing mechanistic-based pavement design method as a part of Korea Pavement Research Program(KPRP). Although the concept of equivalent single axle load(ESAL) has been generally used since the 1960s for the pavement design, the mechanistic-based pavement design procedure requires more accurate axle loading data on the specific pavement. In this study, axle loading data were collected according to vehicle type and highway functional classification. Axle-load spectrum was then standardized by cumulative density function(cdf), because the axle load spectrum could vary from the observed site, truck traffic volume, and truck type, Finally, this study presented the procedure and S-shaped exponential models for characterizing axle load spectra according to vehicle type and highway functional classification.

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Development of Truck Axle Load Distribution Model using WIM Data (WIM 자료를 활용한 화물차 축하중 분포 모형 개발)

  • Lee, Dong Seok;Oh, Ju Sam
    • Journal of The Korean Society of Civil Engineers
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    • v.26 no.5D
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    • pp.821-829
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    • 2006
  • Traffic load comprise primary input to pavement design causing pavement damage. therefore it should be proceeded suitable traffic load distribution modeling for pavement design and analysis. Traffic load have been represented by equivalent single axle loads (ESALs) which convert mixed traffic stream into one value for design purposes. But there are some limit to apply ESALs to other roads because it is empirical value developed as part of the original AASHO(American Association of State Highway Officials) road test. There have been many efforts to solve these problems. Several leading country have implemented M-E(Mechanistic-Empirical) design procedures based on mechanical concept. As a result, they established traffic load quantification method using load distribution model known as Axle Load Spectra. This paper details Axle Load Spectra and presents axle load distribution model based on normal mixture distribution function using truck load data collected by WIM system installed in national highway. Axle load spectra and axle load distribution model presented in this paper could be useful for basic data when making traffic load quantification plan for pavement design, overweight vehicle permit plan and pavement maintenance cost plan.

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Endurance Evaluation and Fatigue Property fo Axle Housing (Axle Housing의 내구성 판단과 피로특성)

  • Byeon, Hui-Mun;Lee, Sun-Bok
    • 한국기계연구소 소보
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    • pp.3-13
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    • 1984
  • Fatigue failure of axle housing could cause many injuries and much financial loss. This challenges the engineer to improve design decisions involving fatigue. Endurance evaluation of axle housing is great interest to auto-mobile manufacturers for the sake of safety and reliability. Axle housing is subjected to gross vehicle weight(G.V.W)as mean load and alternating load. Theoretical design diagram involving mean and alternating stresses is used for the evaluation of axle housing fatigue endurance with the equivalent stress of fatigue critical area on the axle housing. Four point bending fatigue tests on axle housing with constant amplitude loading at approximately R=0 were performed with 50 ton servohydraulic strucural fatigue testing machine developed at KIMM. Specimens were made with the same material STKM 13B as the axle housing and tested to obtain S_N data. Five specimens of STKM 13B were tested at 253.61 MPa and weibull distribution was obtained at the same stress level. Material data and structural data were compares and fatigue stress property factor and fatigue life property factor were obtained.

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Assessment of load carrying capacity and fatigue life expectancy of a monumental Masonry Arch Bridge by field load testing: a case study of veresk

  • Ataei, Shervan;Tajalli, Mosab;Miri, Amin
    • Structural Engineering and Mechanics
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    • v.59 no.4
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    • pp.703-718
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    • 2016
  • Masonry arch bridges present a large segment of Iranian railway bridge stock. The ever increasing trend in traffic requires constant health monitoring of such structures to determine their load carrying capacity and life expectancy. In this respect, the performance of one of the oldest masonry arch bridges of Iranian railway network is assessed through field tests. Having a total of 11 sensors mounted on the bridge, dynamic tests are carried out on the bridge to study the response of bridge to test train, which is consist of two 6-axle locomotives and two 4-axle freight wagons. Finite element model of the bridge is developed and calibrated by comparing experimental and analytical mid-span deflection, and verified by comparing experimental and analytical natural frequencies. Analytical model is then used to assess the possibility of increasing the allowable axle load of the bridge to 25 tons. Fatigue life expectancy of the bridge is also assessed in permissible limit state. Results of F.E. model suggest an adequacy factor of 3.57 for an axle load of 25 tons. Remaining fatigue life of Veresk is also calculated and shown that a 0.2% decrease will be experienced, if the axle load is increased from 20 tons to 25 tons.

Development of Truck Axle Load Estimation Model Using Weigh-In-Motion Data (WIM 자료를 활용한 화물차량의 축중량 추정 모형 개발에 관한 연구)

  • Oh, Ju Sam
    • Journal of The Korean Society of Civil Engineers
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    • v.31 no.4D
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    • pp.511-518
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    • 2011
  • Truck weight data are essential for road infrastructure design, maintenance and management. WIM (Weigh-In-Motion) system provides highway planners, researchers and officials with statistical data. Recently high speed WIM data also uses to support a vehicle weight regulation and enforcement activities. This paper aims at developing axle load estimating models with high speed WIM data collected from national highway. We also suggest a method to estimate axle load using simple regression model for WIM system. The model proposed by this paper, resulted in better axle load estimation in all class of vehicle than conventional model. The developed axle load estimating model will used for on-going or re-calibration procedures to ensure an adequate level of WIM system performance. This model can also be used for missing axle load data imputation in the future.

An Evaluation Study on the Dynamic Stability of High Speed Railway Bridges (고속철도교량의 동적안정성 평가연구)

  • Bang, Myung-Seok;Chung, Guang-Mo
    • Journal of the Korean Society of Safety
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    • v.27 no.4
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    • pp.43-49
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    • 2012
  • In the design of high speed railway bridges is important a impact factor as a tool of assessing the dynamic capacitys of bridges. However, the impact factor(or dynamic amplification factor, DAF) of high speed railway bridges may essentially be changeable because the dynamic response is affected by the long train length(380 m), number of axles and high speed velocity(300 km/h)(Korea Train eXpress: KTX). Therefore, on this study will be examined the dynamic capacity and stability of the typical PSC Box Girder of high speed railway bridge. At first, the static/dynamic analysis is performed considering the axle load line of KTX based upon existing references. Additionally, the KTX moving load is transformed into the dynamic time series load for conducting various parameter studies like axle length, analytical time increment, velocity of KTX. The time history analysis is repeatedly performed to get maximum dynamic responce by varying axle load length, analytical time increment, velocity of KTX. The study shows that dynamic analysis has resonable results with optimal axle load length(0.6 m) and time increment(0.01 sec.) and maximum DAF and dynamic resonance happens at 270 km/h velocity of KTX.

Effects of Tread, Wheelbase and Axle Load Distribution on Tractor Vibrations (윤거, 축거, 차축 하중 분포가 트랙터 진동에 미치는 영향)

  • 조춘환;김경욱
    • Journal of Biosystems Engineering
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    • v.21 no.3
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    • pp.293-305
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    • 1996
  • Effects on the tractor vibrations of tread, wheelbase and axle load distribution were analyzed by using mathematical models of tractor and random road surface. A 4 degrees of freedom tractor model was developed to predict the bounce, pitch and roll motions of tractor. The front axle which is constrained to roll with respect to tractor body was also included in the model. A random road profile was generated and used as an excitation input to the tractor. Output vibrations of the model were predicted and analyzed by a computer simulation method. In general, longer tread tends to reduce rolling and longer wheelbase does bouncing and pitching motions. Tractor vibrations were minimum when the ratio of front to rear axle loads was in the range of 30:70-35:65. Sensitivity analysis showed that rolling and pitching motions most sensitively varied with changes in tread and wheelbase while bouncing motion did with the location of mass center.

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Evaluation of Structural Integrity of Three-axle Bogie Frame used in Railway Freight Cars (평판화차에 사용되는 3축 대차의 구조 안전성 평가)

  • Kang, Seung-Gu;Shin, Kwang-Bok;Im, Jae-Moon;Park, Jung-Joon;Jeon, Seung-Gie
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.26 no.4
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    • pp.436-440
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    • 2017
  • This study evaluated the design and structural integrity of a three-axle bogie frame in a railway freight car through a numerical analysis and an experimental evaluation. A three-axle bogie frame, which supports the weight of the car body and load, is required to transport heavier cargo because two-axle vehicles have structural limitations. Therefore, this study performed a structural analysis and static load tests to evaluate the design and structural integrity of a three-axle bogie frame. The results obtained from the numerical analysis were compared to those of the experiments. For the bogie frame used in the experiments, a failure evaluation was performed using non-destructive methods. The numerical analysis and experimental evaluation were satisfactory for the structural integrity evaluation.