• 한국도로학회논문집
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• 제20권1호
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• pp.9-18
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• 2018

PURPOSES : In this research, the initiation and development of corrugation on a gravel road with certain wheel and boundary conditions were evaluated using a coupled discrete-element method (DEM) with multibody dynamics (MBD). METHODS : In this study, 665,534 particles with a 4-mm diameter were generated and compacted to build a circular roadbed track, with a depth and width of 42 mm and 50 mm, respectively. A single wheel with a 100-mm diameter, 40-mm width, and 0.157-kg mass was considered for the track. The single wheel was set to run slowly on the track with a speed of 2.5 rad/s so that the corrugation was gradually initiated and developed without losing contact between the wheel and the roadbed. Then, the shape of the track surface was monitored, and the movement of the particles in the roadbed was tracked at certain wheel-pass numbers to evaluate the overall corrugation initiation and development mechanism. RESULTS : Two types of corrugation, long wave-length and short wave-length, were observed in the circular track. It seems that the long wave-length corrugation was developed by the longitudinal movement of surface particles in the entire track, while the short wave-length corrugation was developed by shear deformation in a local section. Properties such as particle coefficients, track bulk density, and wheel mass, have significant effects on the initiation and development of long-wave corrugation. CONCLUSIONS : It was concluded that the coupled numerical method applied in this research could be effectively used to simulate the corrugation of a gravel road and to understand the mechanism that initiates and develops corrugation. To derive a comprehensive conclusion for the corrugation development under various conditions, the driver's acceleration and deceleration with various particle gradations and wheel-configuration models should be considered in the simulation.

• 한국측량학회지
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• 제29권6호
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• pp.553-559
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• 2011

자동차 보유대수 증가에 따른 고유가와 온실가스 배출로 자전거이용의 중요성이 대두되고 있지만, 자전거이용률은 현저하게 낮은 실정이다. 자전거이용 활성화를 위한 대책으로 전국자전거도로 사업이 진행되고 있으며 각 지방자치단체에서도 자전거도로 기본계획을 수립하여 진행되고 있다. 노선 선정에 대한 연구가 활발히 진행되고 있지만, 자료 처리에 대한 연구는 명확한 결과를 도출하기엔 부족한 실정이다. 자전거도로 설계 기준에 명시되어진 종단경사도 지형상황 등으로 인하여 부득이하다고 인정되는 경우에는 예외로 한다고 되어 있다. 본 연구에선 기존 자전거도로가 여수시의 지형상황을 고려하여 개설되어 졌는지, 종단경사 기준을 고려하여 연결 가능한 자전거도로 노선 선정을 제시했다. 추가요소로 차선 수, 도로 폭을 포함시켜 개설 가능한 자전거도로 중 적합한 자전거도로 노선이 산출되었다. 향후 산지가 많은 지역을 대상으로 자전거도로 선정 시 종단경사 기준의 활용 방안으로 이용될 것이다.

• Structural Engineering and Mechanics
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• 제61권1호
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• pp.117-124
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• 2017

Load testing is one of the important tests to determine if the structural elements can be used at the intended locations for which they have been designed. It is nothing but gradually applying the loads and measuring the deflections and other parameters. It is usually carried out to determine the behaviour of the system under service/ultimate loads. It helps to identify the maximum load that the structural element can withstand without much deflection/deformation. It will also help find out which part of the element causes failure first. The load-deflection behaviour of the road bridge girder has been studied by carrying out the load test after simulating the field conditions to the extent possible. The actual vertical displacement of the beam at mid span due to the imposed load was compared with the theoretical deflection of the beam. Further, the recovery of deflection at mid span was also observed on removal of the test load. Finally, the beam was checked for any cracks to assert if the beam was capable of carrying the intended live loads and that it could be used with confidence.

• 대한인간공학회지
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• 제21권3호
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• pp.25-34
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• 2002

The road sign in dynamic traffic system is an important element which affects on human cognitive performance on driving. Web-based vision system simulator was developed to examine the cognition time of the road sign in dynamic environment. This experiment the cognition time of the road sign in dynamic environment. This experiment was designed in with-subject design with two factors: vehicle speed and the amount of information of the traffic sign. It measured the cognition time of the road sign through two evaluation methods: the subjective test with vision system simulator and computational cognitive model. In these two evaluations of human cognitive performance under the dynamic traffic environment, it demonstrated that subject's cognition time was affected by both the amount of information of traffic sign and driving speed.

• 대한공간정보학회지
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• 제2권2호
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• pp.89-98
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• 1994

자동차항법장치에 있어서 정확한 위치표현기능, 최적경로안내, 목적지검색, 지형지물정보 제공기능 등을 수행하기 위해서는 수치도로지도가 가장 기본적 요소이다. 그러나, 미국의 TIGER 화일같이 수치도로지도제작에 쉽게 이용될 수 있는 범국가적인 수치지도가 한국에는 마련되어 있지 않으므로, 새로이 제작을 할 수밖에 없는 현실이다. 본 연구에서는 항법용 수치도로지도를 제작함에 있어서 그 호환성과 경제성을 확보하고, 수치도로지도의 질적안정성을 기하기 위한 필요조건을 제시하였으며, 그 결과로 좌표계와 정확도의 기준을 제시하였고, 데이타베이스 항목과 그 구조를 결정하였다.

• 한국안전학회지
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• 제33권5호
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• pp.70-77
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• 2018

In this study, the reinforced methods of joints were proposed to improve the structural performance of the enhanced spun reinforced concrete piles with joints. To verify the proposed methods, flexure performance was validated by finite element analysis considering both material and contact nonlinearity. Based on the previous study and those results of the analysis, it is concluded that the structural performance of the current joints system for the enhanced spun RC piles can be enhanced by applying the reinforced joints composed of extended circular band plates and studs. This proposed method showed the nearest structural behavior to the enhanced spun RC piles without joints. This numerical study will be used to further experimental study on the enhanced spun RC piles with reinforced joints.

• 동력기계공학회지
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• 제13권5호
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• pp.40-45
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• 2009

This article deals with the transient analysis using multi-flexible body dynamics of a trailer vehicle, which is passing a bump on the flat road. In order to investigate the transient dynamic behavior of the trailer, we developed an equivalent finite element model for the trailer and a vehicle dynamic model for the truck using multi-body dynamics. The driving condition considered here is set as the trailer vehicle passes a bump on the flat road in 7km/h. And we investigate the time histories of vertical load and deflections on connecting points between the trailer and truck during the vehicle passes a bump. Due to the dynamic load resulted from the driving condition, additional stress concentrations are found in the trailer and the suspension connecting points between the trailer and rear axles along with kingpin.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2009년도 춘계 학술발표회
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• pp.11-16
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• 2009

Better understanding of in-situ mechanical behavior of pavement foundations is very important to predict long-term effects on the system performance of transport infrastructure. In order to do that, resilient stiffness characterization of geomaterals is needed to properly adopt such mechanistic analysis under both traffic and environmental loadings. In this paper, in situ monitoring data from KHC test road was used to analyze the non-linearity of stress conditions under traffic and moisture loadings. Then, the predicted non-linear response using finite element method with a selected constitutive model of foundation geomaterials are verified with the field data.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 연약지반처리위원회 학술세미나
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• pp.79-92
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• 2000

In this paper, comparison of the observed and the predicted ground deformations due to the construction of road embankment with peck drain near the construction site was made. Measurement of the ground deformation at the gasoline stand due to the construction of road embankment was made and it was compared with the predicted deformation results of Finite Element Method analysis made with Elasto-plastic and Elastic visco-plastic models. A well agreement was obtained between the measured and predicted ground deformations.

• 한국도로학회:학술대회논문집
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• 한국도로학회 2004년도 학술발표회 논문집
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• pp.87-94
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• 2004