• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.20 no.4
• /
• pp.381-389
• /
• 2010

Modern military equipments are often required to be mounted on a truck for their survivability and operation performance. Special units installed on the truck at times experience serious shock vibration caused by obstacles of road and/or uncommon road shape. It is then essential to analyze the travel performance of truck-mounted special units for their survivability and performance. In this paper, shock responses of the equipments subjected to bump passing and wash board road are experimentally obtained and also analyzed via FEM. Modified bump configuration and road profile considering the interface with tire are suggested. Analytical results considering this modification show good agreement with test results.

• Journal of Korean Society on Water Environment
• /
• v.20 no.5
• /
• pp.494-499
• /
• 2004

Growth in population and urbanization has progressively increased the loadings of pollutants from non-point sources as well as point sources. Therefore, it is necessary to manage both point and non-point sources contaminations for protecting water environment and improving water quality. This study investigated the characteristics of pollutant release over a wide range of rainfall intensities as a requisite to control road runoff that accounts for the largest portion of non-point source contamination in urban areas. Samples of runoff rainwater collected from real road surfaces were analyzed for physicochemical parameters such as pH, suspended solids, and heavy metals. A experimental model road ($30cm{\times}30cm$) was also used to evaluate wash-off properties of pollutants deposited on the surface as functions of time and rainfall intensity. Analysis of runoff samples on rain events showed that the pollutant wash-off patterns for heavy metal and suspended solids were similar. This implies that the particles in rainwater adsorb heavy metals. Experiments using the model road made of impervious asphalt demonstrate a strong first flush phenomenon. At high rainfall intensity, approximately 80% of total pollutants were released within 15 min. The pollutant wash-off rates rapidly increase from 9 mm/hr to 12 mm/hr of rainfall intensity and decrease over 12 mm/hr of rainfall intensity.

• International Journal of Highway Engineering
• /
• v.9 no.4
• /
• pp.185-192
• /
• 2007

Newly constructed road is a requisite to be able to carry out BMPs (Best Management Practices) under TMDL(Total Maximum Daily Load) program of the Ministry of Environment. BMPs require pollutant source control during road construction and wash off reduction plan as well as maintenance practices subsequent to construction on the purpose of discharging the minimum wash off non-point source pollutants. The objective of this study is to provide supportive discharged data in evaluating the discharged non-point pollutant load from a highway toll gate area. It can be applied to manage non-point source pollutants on roads. The results validate the first flush phenomenon that it is known to be one of the wash off characteristics in paved area. In addition, the load per unit area and load per unit rainfall duration applying EMC are calculated. The mean load per unit rainfall duration is assessed to be $533.7mg/m^2-hr$ for TSS, $396.2mg/m^2-hr$ for COD, $17.0mg/m^2-hr$ for TN, and $4.8mg/m^2-hr$ for TP. These results show the unitload taken from monitoring are higher than the unit load suggested in the TMDL. It is important to adopt real pollutant unit for road to be able to perform BMP successfully.

• Journal of the Korean Institute of Rural Architecture
• /
• v.14 no.3
• /
• pp.93-100
• /
• 2012

The purpose of this study is to examine the change of inner roads responding to the street system and to examine the how to influence to communal space of village focused on 22 existing old settlements in downtown Cheong Ju. This study examined the types of inner roads based on advanced research. For the research on communal space, interviews with the residents living in the village were conducted to figure out the location and function of it. Also, it was analyzed comparatively with the present communal space. The results are as followings: the width of an inner road has a effect to function of an inner road when flow of an inner road has kept. The function of inner road has been kept when the width of an inner road expanded as pedestrians should be given priority to vehicular traffic. However, the function of inner roads has been changed and the community has been separated when the width of inner roads expanded for vehicular. Because the location of the communal space in the village is affected by the change of the inner road, when the inner road is maintained, the location of the communal space is also maintained, but when the inner road is changed, the location of the communal space is also changed. The communal spaces such as public wells and wash spaces have lost and they have been substituted with senior citizen centers or community centers.

• Journal of Environmental Science International
• /
• v.19 no.6
• /
• pp.665-670
• /
• 2010

Pollutants from urban pavement consists various kinds of substances which are originated from dry deposition, a grind out tire, corrosive action of rain to pavement and facilities and raw materials of the road etc.. These are major pollutants of urban NPS (Non-point source) during rainfall period. However there is not enough information to control such pollutants for appropriate management of natural water quality. In this study of transportation areas, three monitoring stations were set up at trunk road, urban highway and national road in Gyeongnam province. Runoff flow rate was measured at every 15minutes by automatic flow meters installed at the end of storm sewer pipe within the road catchment area for water quality analysis. Data was collected every 15 minutes for initial two hours of rainfall. Additional samples were collected 1-4 hours interval till the end of rainfall. The monitoring parameters were $COD_{Mn}$, SS, T-N & T-P and heavy metals. The average EMCs of TSS and $COD_{Mn}$ were 62.0 mg/L and 24.2 mg/L on the city trunk road, which were higher than those of urban highway and national road, indicating higher pollutant loads due to activities in the city downtown area beside the vehicle. On the other hand, the average EMC of T-N and T-P were in the range of 2.67-3.23 mg/L and 0.19-3.21 mg/L for all the sampling sites. Heavy metals from the roads were mainly Fe, Zn, Cu and Mn, showing variable EMCs by the type of road. From the TSS wash-off analysis in terms of FF(first flush) index, first flush phenomenon was clearly observed in the trunk road(FF : 0.89-1.43). However, such mass delivery behavior was not apparently shown in urban highway(FF : 0.90-1.11) and national road(FF : 0.81-1.41).

• Journal of Korean Society on Water Environment
• /
• v.33 no.2
• /
• pp.123-129
• /
• 2017

The purpose of this study is to identify potential methodologies to reasonably estimate the effectiveness of road vacuum cleaning in terms of pollution loads reduction. In this context, this study proposes two empirical equations to estimate the amount of diffuse pollution loads removed by road vacuum cleaning. The proposed equations estimate the removed amount of pollution loads respectively taking into consideration of: a) the distance of road vacuum cleaning; and b) the amount of road-deposited sediment(RDS). All of the parameters in these equations were evaluated based on results of field monitoring and laboratory analyses, except for the RDS generation rate. The results of this study suggest that pollutant removal efficiency is 46.3% for $BOD_5$ and 56.4% for TP; discharge ratios for particulate and dissolved $BOD_5$ are 35.0% and 21.2%, respectively; discharge ratios for particulate and dissolved TP are 35.0% and 19.4%, respectively. Average concentrations of pollutants in RDS are $BOD_5$ 977.3 mg/kg and TP 317.6 mg/kg. Some results of a case study imply that both equations can be potentially useful if the adopted parameters are reasonably evaluated. In particular, the RDS generation rate should be evaluated based on monitoring data collected from various road conditions.

• Journal of the Korean Institute of Rural Architecture
• /
• v.17 no.2
• /
• pp.51-58
• /
• 2015

10 years ago, in Sijeon-ri, Dogo-myeon, Asan-si, the existing stream was repaired to develope Mt. Dogo trail and irrigation systems through road expansion pavement construction and small stream repair construction. The trees such as persimmon and willow are eliminated that rowed on both sides of the stream and dredging work to dig the rock and sand have been performed. As a result, wide asphalt road was built, also flood damage worries were reduced. 10 years passed and now, how did local residents think about the stream repaired before and after? Village residents, public officials, and the stream construction engineer were interviewed. Villagers indicated a problems that brook became a place where water peppers were taking over and water was stagnating due to the slow velocity so nothing could live and natural landscape like a wash place and the cascade disappeared, because rock and sand were taken out brought soil into the brook. Public officials and engineers were aware of the problems at the time of the stream. Now that construction is completed after 10 years, Both realistically and budgetary to restoration would be difficult. However, it is necessary to seek for waterfront space which can be restored or replaced by a part of the stream like similarly before. In addition, it is necessary to restore to the progression of a natural stream which connect with stairs(or slope) - small waterfalls - pools - wash place. In this paper, we hope to take a lesson from the Sijeon-ri model and make rural stream construction be prepared with consideration about not only distinct characteristics of specific area but also the opinion of local resident.

• Journal of computational fluids engineering
• /
• v.18 no.3
• /
• pp.8-13
• /
• 2013

Drag reduction of a running vehicle is very important issue for the energy savings and emission reduction of its power train. Especially for a solar powered electric vehicle, the drag reduction and weight lightening are two serious problems to be solved to extend its driving distance under the given energy condition. In this study, the ground effect of an airfoil shaped road vehicle was studied for an optimum body design of an ultra-light solar powered electric vehicle. Clark-Y airfoil type was adopted to the body shape of the model vehicle to reduce aerodynamic drag. From the study, it was found that the drag of the model vehicle was reduced as the height(h) between ground and the lower surface of the model vehicle was decreased. It is due to the reduction of the down-wash decreasing the induced drag of the vehicle. The lift was also decreased as the height decreased. It is due to the turbulent boundary layer developed beneath the vehicle body. The drag is classified into two types; the form and friction drag. The fraction of form drag to friction one is 76 to 24 on the model vehicle. As the height(h) of the model vehicle from the ground surface increases the form drag also increases but the friction drag is in reverse.

• Environmental Engineering Research
• /
• v.13 no.4
• /
• pp.184-191
• /
• 2008

Long term monitoring was conducted to investigate a surface runoff of pollution from urban highway. The monitoring data was collected for 18 rainfall events and was used to correlate pollution load to various parameters, such as rainfall intensity, antecedent dry days and total discharge flow. Runoff coefficient and seasonal variation were also evaluated. The mean runoff coefficient of the highway was 0.823(range; $0.4687{\sim}0.9884$), and wash-off ratio for $COD_{Mn}$ and SS loads was 72.6% and 64.3%, respectively. For the initial rainfall event, the runoff EMC of $COD_{Mn}$ was high in summer and the EMC of SS was high in autumn season. However the seasonal variation of T-N and T-P was not significant. The discharged $COD_{Mn}$-EMC was $147.6\;mg/L{\sim}9.0\;mg/L$ on the generated $COD_{Mn}$-EMC of $98.8\;mg/L{\sim}8.9\;mg/L$. While the generated EMC of SS was in $285.7\;mg/L{\sim}20.0\;mg/L$ and its discharged EMC was in $190.4\;mg/L{\sim}8.0\;mg/L$. EMC of pollutants was not directly related to the first flush rainfall intensity and the antecedent dry days. But the correlation was relatively high between EMC and cumulative runoff flow volume. The trend of EMC was reduced with the cumulative runoff flow volume.

• International Journal of Highway Engineering
• /
• v.20 no.1
• /
• pp.117-126
• /
• 2018

PURPOSES : The purpose of this paper is to analyze the change in lane reflection performance through lane washing and sweeping on highway lanes. METHODS : This paper compared and analyzed the changes in lane reflection performance before and after lane washing and sweeping. The research method was as follows. First, we selected four research sites on the Gyeong-bu Highway. Second, the parameters affecting lane reflection performance are classified into luminance, brightness, and number of glass beads. Third, the change in reflection performance was measured after washing /sweeping at the same place after studying 60m of the unwashed/unswept area. Fourth, the measurement results were compared and analyzed before and after lane washing/sweeping. RESULTS : The results of this study are as follows. First, lane washing improved the luminance and brightness by 4.2~21.4% and 1.4~5.1%, respectively, and reduced the number of glass beads per wash by 0.2~1.2%. Second, lane sweeping improved the luminance and brightness by 2.3~8.5% and 0.8~2.3%, respectively, and reduced the number of glass beads per sweep by 0.8~4.9%. CONCLUSIONS : By comparing the results of lane washing and sweeping, it was found that compared to lane sweeping, lane washing improved the luminance and fewer glass beads were dropped.