• 생태와환경
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• 제38권spc호
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• pp.67-75
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• 2005

The objectives of this study were to understand the runoff characteristics of the non-point sources originating from impervious surfaces and to assess their effect on the aquatic environment in the urban areas. The concentration of pollutants (SS, BOD, COD and T-P) except for T-N showed the highest value in runoff from road, and event mean concentration (EMC) also showed high value from road. The pollutants discharged from road showed a higher concentration in the beginning stage (0 ${\sim}$ 30%) of progressive percentage of rainfall. The contribution percentages of non-point sources by load were 44.9% for SS, 11.2% for BOD, 21.4% for COD, 11.4% for T-N and 8.1% for T-P in the total load of pollutant discharged through sewer. From our results, the road was a significant potential source that deteriorated water quality of the streams and lakes in the vicinity of the urban area during the rain period. Therefore, counter plan is required to reduce pollutant concentration on the road from non-point sources in the urban area. Also, since pollutant concentration in the beginning stage of rainfall was quite high, road cleaning seems to be one of the very useful methods to prevent inflowing of pollutants to the aquatic environment.

• Journal of Biosystems Engineering
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• 제21권3호
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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.

• Advances in Computational Design
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• 제7권4호
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• pp.371-393
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• 2022

This paper presents a three-dimensional flexible pavement simulated in ANSYS subjected to moving vehicular load on the surface of the pavement typical for the road section in Nepal. The adopted finite element (FE) model of pavement is validated with the classical theoretical formulations for half-space pavement. The validated model is further utilized to understand the damping and dynamic response of the pavement. Transient analysis of the developed FE model is done to understand the time varying response of the pavement under a moving vehicle. The material properties of pavement considered in the analysis is taken from typical road section used in Nepal. The response quantities of pavement with nonlinear viscoelastic asphalt layer are found significantly higher compared to the elastic pavement counterpart. The structural responses of the pavement decrease with increase in the vehicle speed due to less contact time between the tires of the vehicle and the road pavement.

• 한국도로학회논문집
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• 제17권6호
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• pp.37-45
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• 2015

PURPOSES : The purpose of this study is to validate the design criteria of the concrete modular road system, which is a new semi-bridge-type concept road, through a comparison of numerical analysis results and actual loading test results under static axial loads. METHODS : To design the semi-bridge-type modular road, both the bridge design code and the concrete structural design code were adopted. The standard truck load (KL-510) was applied as the major traffic vehicle for the design loading condition. The dimension of the modular slab was designed in consideration of self-weight, axial load, environmental load, and combined loads, with ultimate limit state coefficients. The ANSYS APDL (2010) program was used for case studies of center and edge loading, and the analysis results were compared with the actual mock-up test results. RESULTS : A full-scale mock-up test was successfully conducted. The maximum longitudinal steel strains were measured as about 35 and 83.5 micro-strain (within elastic range) at center and edge loading locations, respectively, under a 100 kN dual-wheel loading condition by accelerating pavement tester. CONCLUSIONS : Based on the results of the comparison between the numerical analysis and the full-scale test, the maximum converted stress range at the edge location is 32~51% of the required standard flexural strength under the two times over-weight loading condition. In the case of edge loading, the maximum converted stresses from the Westergaard equation, the ANSYS APDL analysis, and the mock-up test are 1.95, 1.7, and 2.3 times of that of the center loading case, respectively. The primary reason for this difference is related to the assumption of the boundary conditions of the vertical connection between the slab module and the crossbeam module. Even though more research is required to fully define the boundary conditions, the proposed design criteria for the concrete modular road finally seems to be reasonable.

• 한국도로학회논문집
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• 제19권4호
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• pp.27-36
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• 2017

PURPOSES : The purpose of this study is to perform a reliability analysis of the proposed wind load combination which governs the design of support structures of subsidiary road facilities, and to evaluate whether the target reliability of the design is satisfied. METHODS : The statistical estimation method is applied and the design period of the support structure is used to obtain the statistical property of the wind load. In addition, the statistical properties of the strength of support structures are obtained from a literature review and simulation study. Actual support structures are designed by the proposed load combination and are used as the examples to examine if the target reliability is obtained. RESULTS : The result of the reliability analysis performed by using the statistical properties of load and resistance for the support structure in this study indicates that the proposed wind load combination satisfied the target reliability index of the design. Also, the convenience of the design is achieved by adopting the same design wind velocity given in the bridge design code by applying the wind velocity ratio defined for the design period of the support structure. CONCLUSIONS : It is presented that the design using the wind load combination proposed in this study achieved the target reliability index and the design wind load for different design periods can be conveniently defined by applying the velocity ratio proposed in this study.

• 대한기계학회논문집 C: 기술과 교육
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• 제5권2호
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• pp.115-126
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• 2017

본 논문은 특수 차량용 동력 전달계 부품인 구동축의 가속 수명 시험을 수행하는 것이다. 동력 전달계 부품의 수명 평가를 위하여 사용환경의 주행 부하 스펙트럼의 데이터가 필요하나, 특수 차량의 경우 부하 스펙트럼을 구할 수 없는 경우가 대부분이다. 따라서, 본 논문에서는 차량 데이터와 특수 주행로 조건에 기반하여 주행 부하 로드 스펙트럼을 모델링하고 시뮬레이션 하였다. 가속 수명 시험에는 역승 모델을 적용하였고, 마이너 법칙을 사용하여 등가 토크를 구하였으며, 구동축 가속 수명 시험을 위하여 교정 가속법을 사용하였다. 피로시험은 세 수준의 스트레스로 수행하였으며, 사용자 스트레스 수준의 수명은 외삽법을 사용하여 예측 하였고, 실제 시험 결과와 부하 스펙트럼 데이터와의 비교로 수명을 검증하였다.

• 한국물환경학회지
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• 제25권5호
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• pp.689-696
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• 2009

Unit load approach has been used to estimate the non-point pollutant load in Total Water Pollution Load Management System (TWPLMS). In this study, locally applicable unit loads for road and parking lot were developed based on the measurements of 9 rainfall events from 2007 to 2008 in Yongin city of Gyeongan stream watershed. Observations showed that stormwater runoff began at low precipitation (>1 mm) and peak pollutant concentration occurred at the beginning of the runoff because of impervious nature of the sites. Averaged event mean concentrations (EMCs) of road (parking lot) were estimated as COD 105.36(62.69) mg/L, BOD 15.94(13.20) mg/L, TSS 183.45(66.52) mg/L, T-N 4.63(3.28) mg/L, T-P 0.45(0.39) mg/L. Higher EMCs at the road than parking lot may reflect heavier traffic. Unit loads Estimated from the EMCs and 10 year average rainfall data were COD $331.17kg/km^2{\cdot}day$, BOD $50.20kg/km^2{\cdot}day$, TSS $580.13kg/km^2{\cdot}day$, T-N $14.68kg/km^2{\cdot}day$, T-P $1.43kg/km^2{\cdot}day$ in the road and COD $186.59kg/km^2{\cdot}day$, BOD $39.22kg/km^2{\cdot}day$, TSS $199.15kg/km^2{\cdot}day$, T-N $9.70kg/km^2{\cdot}day$, T-P $1.16kg/km^2{\cdot}day$ in the parking lot. The estimated unit loads are not so comparable to the ones listed in TWPLMS technical guideline and published data that locally developed unit loads should be used to estimate non-point pollutant loads.

• Geomechanics and Engineering
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• 제9권2호
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• pp.219-241
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• 2015

In this paper, a series of repeated load tests were carried out on a 150 mm diameter plate simulative of vehicle passes, to demonstrate the benefits of soil-rubber shred mixture in decreasing the soil surface settlement of road embankment. The results show that the efficiency of rubber reinforcement is significantly a function of the rubber content, thickness of rubber-soil mixture and soil cap thickness over the mixture. Minimum surface settlement is provided by 2.5% of rubber in rubber-soil mixture, the thickness of mixture layer and soil cap of 0.5 times the loading surface diameter, giving values of 0.32-0.68 times those obtained in the unreinforced system for low and high values of amplitude of repeated load. In this installation, in contrast with unreinforced bed that shows unstable response, the rate of enhancement in settlement decreases significantly as the number of loading cycles increase and system behaves resiliently without undergoing plastic deformation. The findings encourage the use of rubber shreds obtained from non-reusable tires as a viable material in road works.

• Journal of Biosystems Engineering
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• 제37권3호
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• pp.148-154
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• 2012

Purpose: In order to improve road-friendliness of heavy vehicles, a fuzzy hybrid control strategy consisting of a hybrid control strategy and a fuzzy logic control module is proposed. The performance of the proposed strategy should be effectively evaluated using a hardware-in-the-loop (HIL) simulation model of a semi-active suspension system based on the fuzzy hybrid control strategy prior to real vehicle implementations. Methods: A hardware-in-the-loop (HIL) simulation system was synthesized by utilizing a self-developed electronic control unit (ECU), a PCI-1711 multi-functional data acquisition board as well as the previously developed quarter-car simulation model. Road-friendliness of a semi-active suspension system controlled by the proposed control strategy was simulated via the HIL system using Dynamic Load Coefficient (DLC) and Dynamic Load Stress Factor (DLSF) criteria. Results: Compared to a passive suspension, a semi-active suspension system based on the fuzzy hybrid control strategy reduced the DLC and DLSF values. Conclusions: The proposed control strategy of semi-active suspension systems can be employed to improve road-friendliness of road vehicles.

• 한국소음진동공학회논문집
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• 제17권3호
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• pp.274-281
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• 2007

Road traffic noise is not produced by any one factor rather it occurs as a composition of various factors. Its occurrence is made by running engine noise, tire frictional, and exhaust noise etc. The quality of the noise depends on the size of the vehicles, rotation and engine speed, vehicle load, package state of the road and incline etc. The occurrence of any noise level of heavy trucks appears louder than smaller vehicles and the noise levels produced differs according to speed and load etc between similar size vehicles. Other factors such as traffic density, average speed, mixing rate of heavy vehicles, and the distance between vehicles also generate road traffic noise. In this paper we examine 2, 4, and 6-lane roads in Jeonju. Consequently, this study examines the means used to measure road traffic noise. It was found that when there is a large traffic density and the average velocity is below 70 km/h, the noise level could receive a relative proper value by the current measuring means. But in the case of night-time, it was found that the current measuring method is inapposite.