• Journal of environmental and Sanitary engineering
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• v.16 no.4
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• pp.31-37
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• 2001

Deicers have used for melting snow on the road during winter season, but they have largely influenced on environment and public assets and human health. The pollution level of snow and soil contained deicer was analyzed and evaluated the characteristics of deicers. The results were as follows 1. In the result of measurement of pollutants in snow contained deicer, the pH was a little higher than a comparative group and the concentration of $Cl^{-}$ ranged from 0.5% to 0.87%, and the electric conductivity ranged 12.4 to 24.6 mmho/cm. The concentration of Cd, As, and Hg was not detected, but those of Cu, Pb, Cr was higher than a comparative group. 2. In soil of the road spreaded with deicer, the pH is getting alkalized and the concentration of $Cl^{-}$ was high in January and returned the level of a comparative grout) in November by physical and chemical reaction with deicer, but the concentration of heavy metals were not connected with deicers. 3. In comparison of deicing efficiency, the concentration of $Cl^{-}$ was 3.3~5times high in spreading with deicer before snowing than after snowing. The concentration of $Cl^{-}$ in NaCl was higher than $CaCl_2$, but the deicing efficiency of Nacl was better than that of $CaCl_2$. Moreover, the new deicer have no salt, but deicing efficiency of new deicer was less than that of NaCl and $CaCl_2$.

• Journal of The Korean Society of Agricultural Engineers
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• v.51 no.3
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• pp.71-78
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• 2009

Pipe section of bending part at the arch type pipe-house showed an ellipse with oblateness of 0.076 on the average. Flexural rigidity of bending part decreased by average 6.3% than that of an original round shape section. The deflection of arch type pipe-house measured by model experiments showed much bigger than the result of structural analysis. In case of arch type pipe-house, we supposed that the decrease of flexural rigidity for the bending part of pipes had an effect on deflection of roof under the working load. This effect should be considered in the structural analysis. Bending resistance of gable type pipe-house used a prefabricated connector which developed in this study showed about $1.5{\sim}1.8$ times stronger than that of the existing arch type or gable type processed bending. Therefore, we supposed that the gable-roofed prefabricated pipe-house is safer than arch type or bent gable type in case of heavy snowfall. According to house scales and section properties of steel pipe in use, safe snow depths and rafter intervals were presented for design of gable-roofed prefabricated pipe-house. Their standards were established in the range of the durable models recommended by RDA, and the comparative examinations were conducted by means of structural analysis. It was evaluated that the developed greenhouse model had a high applicability in the field.

• Journal of the Korean Institute of Rural Architecture
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• v.18 no.2
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• pp.11-18
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• 2016

The collapsing accidents of greenhouse frames have been increased yearly due to strong wind and heavy snow, but as it was, there were few studies about the structural safety of greenhouses. Therefore, this study was carried out to develop the stress tolerant structural frame systems in built-up greenhouses. The vertical loading experiment of developed scale models were implemented and the developed types of models were simulated by 3-D analysis program in this study. These types of models, which are existing type and honeycomb type, in arch and standard style frames were classified. As a result of this study, it was verified that the honeycomb type model of arch style frame is better than the existing type model of it in stress resistance against snow load and wind load.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06a
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• pp.105-110
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• 2006

In order to utilize coal fly ash (hereafter : coal ash ) discharged from coal boiler as a material for civil engineering usage such as snow melter or soil improver, we have to prevent leaching hazardous elements such as fluorine boron and heavy metals from the coal ash because the leaching concentrations of some elements in the ash exceed the Japanese standards for environmental soil quality. Through the laboratory experiments and mill trials we confirmed that the leaching concentrations of fluorine, boron and heavy metals were maintained below their environmental standards by mixing with fixation chemicals and curing for a short time.

• Structural Engineering and Mechanics
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• v.62 no.5
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• pp.567-576
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• 2017

Structural failures are undesirable events that devastate the construction industry resulting in loss of life, injury, huge property loss, and also affect the economy of the region. Roof truss failures occur mainly due to excessive loading, improper fabrication, deterioration, inadequate repair, etc. Although very rare, a roof truss may even fail due to inappropriate location of supports. One such case was reported from the recent failure of a steel roof truss used in an indoor stadium at Kargil in India. Kargil region, being mountainous in nature, receives heavy snowfall and hence the steel roof trusses are designed for heavy snow loads. Due to inappropriate support location, the indoor stadium's steel roof truss had failed under heavy snow load for which it was designed and became an interesting structural engineering problem. The failure observed was primarily in terms of yielding of the bottom chord under the supports, leading to partial collapse of the roof truss. This paper summarizes the results of laboratory tests and analytical studies that focused on the validation of the proposed remedial measure for rehabilitating this distressed steel roof truss. The study presents the evaluation of (i) significant reduction in strength and stiffness of the distressed truss resulting in its failure, (ii) desired recovery in both strength and stiffness of the rectified truss contributed by the proposed remedial measure. Three types of models i.e., ideal truss model, as build truss model and rectified truss model were fabricated and tested under monotonic loading. The structural configuration and support condition varied in all the three models to represent the ideal truss, distressed truss and the rectified truss. To verify the accuracy of the experimental results, an analytical study was carried out and the results of this analytical study are compared with the experimental ones.

• Journal of Korean Society for Atmospheric Environment
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• v.16 no.5
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• pp.487-497
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• 2000

Spring time is a favorable season to be easily observed the Yellow Sand phenomenon in East Asia. In particular most of the phenomenon tend to occur in April. However, Yellow Sand phenomenon was observed from almost the whole country of Korea in winter of 1966, 1977 and 1999. The features of the synoptic weather pattern in the source regions, air stream flow between the source region and Korea, the measurement of TSP concentration, aerosol size distribution, and chemical composition of snow samples associated with Yellow Sand phenomenon were investigated. The result showed the characteristic evolutionary feature of the synoptic system associated with Yellow Sand phenomena, that is, a strong low level wind mobilized the dust within 2 or 3 days before Yellow Sand phenomenon being observed in Seoul. The wind was remarkably intensified in the source region on January 24, 1999 under the strong pressure gradient, A trajectory analysis showed that the Yellow Sand particle could be reached to Korea within 2 days from the source region, Gobi desert, through Loess plateau and Loess deposition region. The TSP concentration at the top of Kwanak mountain during the Yellow Sand phenomenon is abruptly increasing than the monthly mean concentration. The size resolved number concentration of aerosols ranging from 0.3 to 25${\mu}{\textrm}{m}$ was analyzed during Yellow Sand episode. It was evident that aerosols were distinguished by particles in the range of 2-3 ${\mu}{\textrm}{m}$ to result in the abrupt increase in January 1999, After Yellow Sand phenomenon, there was heavy snow in Seoul. By the analysis of snow collected during that time, it was observed that both the Ca(sup)2+ concentration and pH were increased abnormally compared to those in the other winter season.

• Journal of Korean Society of Steel Construction
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• v.22 no.1
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• pp.67-74
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• 2010

The cases of collapse of greenhouses in rural areas have been increasing due to the unexpected heavy snow load. Studies on how to prevent the collapse of greenhouses are rare, however, and the damages are repeated annually. This studysuggests two reinforcing methods: the use of ahigh-strength tapered module, and the addition of a pre-tension tie. The high-strength tapered section is installed where the bending moment is maximum. The design of a plastic greenhouse is controlled by its strength rather than its deflection. The shape of a greenhouse resembles that of an arch system, but its actual structural behavior is the frame behavior, because it is non-continually composed of a curved element (a beam) and vertical elements (columns). This system is too weak and slender to resist a vertical load, because an external load is resisted by the moment rather than by axial force. In this study, a new method, the installation of a temporary tie at the junction of the arch and the column only during snow accumulation, is proposed. The tie changes the action of the greenhouse frame to an arch action. The arch action is more effective when the pre-tension force is applied in the tie, which results in a very strong temporary structural system during snowfall. As a result of using this high-strength tapered section, the combined strength ratio of what? decreased from 10% to 30%. In the case of the additional reinforcement with a tie, it was reduced by half.

• Atmosphere
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• v.26 no.2
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• pp.227-241
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• 2016

This study investigated the cause of the heavy snowfall that occurred in the East Coast of Korea from 6 February to 14 February 2014. The synoptic conditions were analyzed using blocking index, equivalent potential temperature, potential vorticity, maritime temperature difference, temperature advection, and ground convergence. During the case period, a large blocking pattern developed over the Western Pacific causing the flow to be stagnant, and there was a North-South oriented High-to-Low pressure system over the Korean Peninsula because of this arrangement. The case period was divided into three parts based on the synoptic forcing that was responsible for the heavy snowfall; detailed analyses were conducted for the first and last period. In the first period, a heavy snowfall occurred over the entire Korean Peninsula due to strong updrafts from baroclinic instability and a low pressure caused by potential vorticity located at the mid-troposphere. In the lower atmosphere, a North-South oriented High-to-Low pressure system over the Eastern Korea intensified the easterly airflow and created a convergence zone near the ground which strengthened the upslope effect of the Taebaek Mountain range with a cumulative fresh snowfall amount of 41 cm in the East Coast region. In the last period, the cold air nestled in the Maritime Province of Siberia and Manchuria strengthened much more than that in the first half and extended to the East Sea. The temperature difference between the 850 hPa air and the SST was large and convective clouds developed over the sea. The highest cumulative fresh snow amount of 39.7 cm was recorded in the coastal area during this period. During the entire period, vertically oriented equivalent potential temperature showed neutral stability layer that helped the cloud formation and development in the East Coast. The 2014 heavy snowfall case over the East Coast provinces of Korea were due to: 1) stagnation of the system by blocking pattern, 2) the dynamic effect of mid-level potential vorticity of 1.6 PVU, 3) the easterly air flow from North-South oriented High-to-Low pressure system, 4) the existence of vertically oriented neutral stable layer, and 5) the expansion of strong cold air into the East Sea which created a large temperature difference between the air and the ocean.

• Journal of the Korean Geographical Society
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• v.45 no.3
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• pp.319-341
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• 2010

The purposes of this study are to classify heavy snowfall types in the Republic of Korea based on fresh snowfall data and atmospheric circulation data during the last 36(1973/74-2008/09) snow seasons and to identify typical surface synoptic climate patterns that characterize each heavy snowfall type. Four synoptic climate categories and seventeen regional heavy snowfall types are classified based on sea level pressure/surface wind vector patterns in East Asia and frequent spatial clustering patterns of heavy snowfall in the Republic of Korea, respectively. Composite analyses of multiple surface synoptic weather charts demonstrate that the locations and intensity of pressure/wind vector mean and anomaly cores in East Asia differentiate each regional heavy snowfall type in Korea. These differences in synoptic climatic fields are primarily associated with the surge of the Siberian high pressure system and the appearance of low pressure systems over the Korean Peninsula. In terms of hemispheric atmospheric circulation, synoptic climatic patterns in the negative mode of winter Arctic Oscillation (AO) are also associated with frequent heavy snowfall in the Republic of Korea at seasonal scales. These results from long-term synoptic climatic data could contribute to improvement of short-range or seasonal prediction of regional heavy snowfall.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2005.10a
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• pp.131-137
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• 2005