• Title/Summary/Keyword: 반복 교통하중

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Analysis of Permanent Deformation under Repetitive Load Based on Degraded Secant Modulus (할선탄성계수를 이용한 반복하중 하 지반의 영구변형 해석)

  • Ahn, Jaehun;Oh, Jeongho;Shin, Hosung
    • Journal of the Korean Geotechnical Society
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    • v.29 no.2
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    • pp.15-21
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    • 2013
  • The analysis of long-term performance of pavement sections under wheel loads is normally conducted in two separated steps. First the resilient behavior of the pavement is calculated assuming the pavement is a layered or discrete elastic medium, and then the permanent deformation is evaluated based on empirical permanent displacement equations. Material properties required in both steps can be obtained from cyclic triaxial tests, in other words, resilient and permanent deformation tests. While this analytical approach is simple and convenient, it does not consider the modulus degradation caused by cyclic loads, and some types of reinforcements such as geosynthetic cannot be modeled in this type of analysis. A model for degraded secant modulus is proposed and suggested to be used for the analysis of permanent behavior of unpaved roadway sections. The parameter for suggested model can be obtained from cyclic triaxial tests, regular practice in pavement engineering. Examples to estimate the model parameters are presented based on both laboratory permanent deformation test and large-scale plate load test.

Dynamic shear behavior of geosynthetic-soil interface considering thermalchemical factors (열-화학적 인자를 고려한 복층터널의 지반-토목섬유의 접촉면 전단거동)

  • Jang, Dong-In;Kwak, Chang-Won;Park, Inn-Joon
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.18 no.2
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    • pp.213-220
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    • 2016
  • The needs for the utilization of space in the urban ara due to the increasing population and traffic volume. A Double-deck tunnel can be an appropriate solution. Geosynthetics are inevitably installed between ground and tunnel lining, therefore, geosynthetic-soil interface is also comprises. Dynamic shear behavior of geosynthetic-soil interface affects the dynamic behavior of tunnel, and experimental study is required since the behavior is very complicated. In this study, chemical factors such as acid and basic element in the groundwater and temperature are considered in the laboratory test. Multi-purpose Interface Apparatus(M-PIA) is utilized and submerging periods are 60 and 960 days. Consequently, dynamic shear degradation of geosynthetic-soil interface considering chemical and thermal factors are verified.

Fatigue Field Test of Variable Message Sign Structure and Evaluation of AASHTO Specifications (가변정보판이 설치된 지주구조물에 대한 피로 시험 및 AASHTO설계기준 적용성 평가)

  • Park, Jong Sup
    • Journal of Korean Society of Steel Construction
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    • v.18 no.1
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    • pp.11-22
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    • 2006
  • Message Signs (VMS) structures offer an increase in traffic safety through their ability to relay massages to motorists for warnings of hazards ahead, traffic congestion, accidents, and lane closings. The geometry of these signs sometimes results in the significant cyclic loading of the supports structure due to wind gusts, which can result from passing trucks or from natural wind. This study presents the results of analytical and experimental investigations of VMS structures. The commercially available softwareGTSTRUDL (2003) was used to perform space-frame structural analyses of these welded tubular structures. Fatigue evaluations were performed using stress ranges from field measurements and from structural analyses. Based on the results of the structural analyses that were conducted, where fatigue design loadings that had been derived from AASHTO Specifications for Structural Supports for Highway Signs, Luminaries, and Traffic Signals (2001) were used, the structures that had been studied were found not to have infinite fatigue life. According to the limited measurements that were made in this study, the fatigue design loadings derived from AASHTO Specifications (2001) appear to be conservative, but they are not overly conservative. The results of this study should be used to make a reasonable design of VMS structures, and to maintain their standards.

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
    • KSCE Journal of Civil and Environmental Engineering Research
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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.

Prediction of Resilient Deformation and Stress-Dependent Behaviors on Geomaterials in Pavement Foundation (도로기초 지반재료의 회복변형 및 응력의존 예측)

  • Park, Seong-Wan;Hwang, Kyu-Young
    • International Journal of Highway Engineering
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    • v.10 no.1
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    • pp.63-74
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    • 2008
  • Resilient deformation characteristics on unbound pavement materials have been adopted for design and nonlinear analysis of pavement structure under traffic loadings. However, relatively few studies have been done on the nonlinear resilient behavior of unbound pavement materials in Korea. In addition, only the limited information is available for estimating the resilient modulus values on unbound materials. In this study, a laboratory resilient-deformation test under repeated loadings is performed in order to fud a proper constitutive model that correlates the resilient modulus with stress state from field condition. Finally, a finite element analysis is conducted for evaluating the nonlinear characteristics of unbound materials. and the pavement performance respectively.

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A Study on Statistical Analysis of Load Carrying Capacity of Steel Bridges (강도로교의 내하력 통계분석과 해석에 관한 연구)

  • Chang, Dong Il;Lee, Hee Hyun;Eom, Yeong Ho
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.8 no.1
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    • pp.41-48
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    • 1988
  • Fatigue phenomena usually occur in the structures such as bridges subjected to repeated loading with increasing service year. Especially, applied stresses happen to approach to design values due to rapid increase of traffic volume and vehicle weight, so it gives serious effects to the stability of bridges. Therefore, in this paper, the data for load carrying capacity of bridges obtained from field tests were analysed statistically to investigate bridge behaviour and a basic approach to estimate the impact factor was proposed after a comparison war made between field-test data and the calculated values obtained by using matrix structural analysis method.

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Evaluation of the Permanent Deformation Behavior on Geosynthetics-Reinforced Asphalt Pavement by using the Wheel Tracking Tests (휠트래킹 시험을 통한 토목섬유시트 보강 아스팔트포장의 소성변형 거동특성 평가)

  • Cho, Sam-Deok;Lee, Dae-Young;Kim, Jin-Hwan;Kim, Nam-Ho
    • Journal of the Korean Geosynthetics Society
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    • v.2 no.3
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    • pp.39-46
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    • 2003
  • The major pavement distress types found in the domestic roadways include rutting, fatigue cracking, and reflection cracking which are results of the environment and repeated traffic loads. These distresses usually occur before pavements approach their design life, and therefore, a significant amount of national budget is spent for maintenance of roadway pavements. The purpose of this study is to establish a geosynthetics-asphalt pavement system. For the study, wheel tracking tests are conducted to analyze the controlling effect of geosynthetics on rutting of asphalt pavement. On the basis of these works, the reinforcement effect of geosynthetics on the rutting of the asphalt pavement is clarified and deformation characteristics of geosynthetics-asphalt mixture is examined.

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Development of the Permanent Deformation Prediction Model of 19mm Dense Grade Asphalt Mixtures (19mm 밀입도 아스팔트 혼합물의 소성변형 예측 모델 개발)

  • Park, Hee-Mun;Choi, Ji-Young;Park, Seong-Wan
    • International Journal of Highway Engineering
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    • v.7 no.4 s.26
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    • pp.1-8
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    • 2005
  • Permanent Deformation is one of the most important load-related pavement distresses in asphalt pavements. The Korean Pavement Design Guide currently being developed adopted the mechanistic-empirical approach and needed the pavement distress prediction models. This study intends to develop the model for prediction of permanent deformation in the asphalt layer and estimate the pavement performance. The objectives of this paper are to figure out the factors affecting the permanent deformation and then develop the permanent deformation prediction model for asphalt mixtures. The repeated triaxial load test was Performed on the 19mm dense graded asphalt mixture with variation of temperature and air void. Results from the laboratory tests showed that temperature and air void in asphalt mixtures have significantly influenced on the factors in prediction model. The permanent deformation prediction model for 19m dense grade asphalt mixtures has been developed using the multiple regression approach and validated the proposed permanent deformation prediction model.

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A Study on the Analysis of Bridge Safety by Truck Platooning (차량 군집 주행에 따른 교량 안전성 분석에 관한 연구 )

  • Sangwon Park;Minwoo Chang;Dukgeun Yun;Minhyung No
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.27 no.2
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    • pp.50-57
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    • 2023
  • Autonomous driving technologies have been gradually improved for road traffic owing to the development of artificial intelligence. Since the truck platooning is beneficial in terms of the associated transporting expenses, the Connected-Automated Vehicle technology is rapidly evolving. The structural performance is, however, rarely investigated to capture the effect of truck platooning on civil infrastructures.In this study, the dynamic behavior of bridges under truck platooning was investigated, and the amplification factor of responses was estimated considering several parameters associated with the driving conditions. Artificial intelligence techniques were used to estimate the maximum response of the mid span of a bridge as the platooning vehicles passing, and the importance of the parameters was evaluated. The most suitable algorithm was selected by evaluating the consistency of the estimated displacement.

Precast Segmental PSC Bridge Columns with Precast Concrete Footings : I. Development and Verification of System (조립식 기초부를 갖는 프리캐스트 세그먼트 PSC 교각 : I. 시스템 개발 및 검증)

  • Kim, Tae-Hoon;Park, Se-Jin;Kim, Young-Jin
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.4A
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    • pp.395-405
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    • 2009
  • The purpose of this study was to investigate the performance of precast segmental PSC bridge columns with precast concrete footings. The proposed system can reduce work at a construction site and makes construction periods shorter. The precast concrete footings is intended to support precast segmental PSC bridge columns and provides an alternative to current cast-inplace systems, particularly for areas where reduced construction time is desired. Shortened construction time, in turn, leads to important safety and economic advantages when traffic disruption or rerouting is necessary. A model of precast segmental PSC bridge columns was tested under a constant axial load and a cyclically reversed horizontal load. In the companion paper, the experimental and analytical study for the performance assessment of precast segmental PSC bridge columns with precast concrete footings is performed.