• Journal of The Geomorphological Association of Korea
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• v.28 no.2
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• pp.71-85
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• 2021

In this study, the effect on the spatial distribution and diffusion of Arishigona, Sanaji and Bang-gae appearing in Jeolla-do was analyzed using geomorphic elements. Based on result, the AriShigona is distributed in the western plains of the Yeongsan River basin and around from the Noryeong mountain range to Mudeung mountain range, the Sanaji is mainly diffused in the middle and upper parts of the Seomjin River and the lower parts of the Mangyeong River, Dongjin River and the Boseong River basin, and the Bang-gae is found to be distributed in the Seomjin River and the upper part of the Yeongsan River basin. Although the cultural centers of these Rice-paddy Weeding Songs are different but they appear to have a similar distribution pattern in Jeolla-do. This is used as a diffusion path of cultural elements by crossing lineaments in various directions and serving bridge role at the same time. However, in the region where the lineaments do not intersect, the continuity of Rice-paddy Weeding Songs are relatively low, which are considered to be reflected in the spatial distribution and propagation of the sound due to the influence of the drain network rather than the lineament. The results of this study can provide basic data for spatial distribution of Rice-paddy Weeding Songs, and regionality and cultural division by diffusion characteristics.

• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.462-470
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• 2006

The zooplankton community dynamics and grazing experiments was evaluated along a 40 km section of the lower Seomjin river system. Zooplankton was sampled twice a month from January 2005 to June 2006 at three sites (River mouth; RKO, Seomjin bridge: RK12 and Gurae bridge: RK36) in the main river channel. During the study period, the values of most limnological parameters in the three sites were fairly similar, except for conductivity. Annual variation of conductivity in River mouth and Seomjin bridge was more dramatic than which of the other site. There were statistically significant spatial and seasonal differences in zooplankton abundance (ANOVA, P<0.01). Total abundance of major zooplankton groups at both stations was much higher than in Gurae bridge. Among the macrozooplankton, cladocerans abundance was negligible in study sites during study periods. Community filtering rates (CFRs) for phytoplankton and bacteria varied from 0 to 50 mL $L^{-1}\;D^{-1}$ and from 0 to 45 mL $L^{-1}\;D^{-1}$, respectively. The spatial variation of CFRs for phytoplankton was significant (ANOVA, P<0.05). The CFRs of copepods for phytoplankton and bacteria was much higher than that of cladocerans at study sites. Total zooplankton filtering rates on bacteria were slightly lower than filtering rates on phytoplankton. The CFRs of microzooplankton (MICZ) for bacteria were much higher than for macrozooplankton (MACZ) at all sites. Considering the total zooplankton community, MICZ generally were more important than MACZ as grazers of bacteria and phytoplankton in freshwater zone, while MACZ were more important than MICZ as grazers of phytoplankton in brackish zone.

• Computers and Concrete
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• v.12 no.2
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• pp.169-186
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• 2013

The aim of this paper is to determine the effect of soil-structure interaction and time dependent material properties on behavior of concrete box-girder highway bridges. Two different finite element analyses, one stage and construction stage, have been carried out on Komurhan Bridge between Elazi$\breve{g}$ and Malatya province of Turkey, over Fırat River. The one stage analysis assume that structure was built in a second and material properties of structure not change under different loads and site conditions during time. However, construction stage analysis considers that construction time and time dependent material properties. The main and side spans of bridge are 135 m and 76 m, respectively. The bridge had been constructed in 3 years between 1983 and 1986 by balanced cantilever construction method. The parameters of soil-structure interaction (SSI), time dependent material properties and construction method are taken into consideration in the construction stage analysis while SSI is single parameter taking into consideration in the one stage analysis. The 3D finite element model of bridge is created the commercial program of SAP2000. Time dependent material properties are elasticity modulus, creep and shrinkage for concrete and relaxation for steel. Soft, medium, and firm soils are selected for evaluating SSI in both analyses. The results of two different finite element analyses are compared with each other. It is seen that both construction stage and SSI have a remarkable effect on the structural behavior of the bridge.

• Structural Engineering and Mechanics
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• v.29 no.2
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• pp.135-154
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• 2008

The moving vehicle loads on a bridge deck is one of the most important live loads of bridges. They should be understood, monitored and controlled before the bridge design as well as when the bridge is open for traffic. A MOM-based algorithm (MOMA) is proposed for identifying the timevarying moving vehicle loads from the responses of bridge deck in this paper. It aims at an acceptable solution to the ill-conditioning problem that often exists in the inverse problem of moving force identification. The moving vehicle loads are described as a combination of whole basis functions, such as orthogonal Legendre polynomials or Fourier series, and further estimated by solving the new system equations developed with the basis functions. A number of responses have been combined, some numerical simulations on single axle, two axle and multiple-axle loads, being either constant or timevarying, have been carried out and compared with the existing time domain method (TDM) in this paper. The illustrated results show that the MOMA has higher identification accuracy and robust noise immunity as well as producing an acceptable solution to ill-conditioning cases to some extent when it is used to identify the moving force from bridge responses.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.1
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• pp.61-69
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• 2024

An ultra-high strength prestressed prismatic beam of 100 MPa in compressive strength was developed by increasing the water-tightness of concrete by utilizing centrifugal molding processes without adding expensive admixtures. The centrifugal prismatic PSC beam developed as the superstructure of the avalanche tunnel was constructed on a rahmen bridge in a small local river. In this study, the centrifugal prismatic beam was compared and analyzed based on the results of measurements made through static load tests and the results of numerical analysis of the target structure. The common load-carrying capacity and safety of the rahmen bridge were evaluated. The static·dynamic load tests and finite element analysis results of this bridge were similar, and it was confirmed that the behavior of the centrifugal prismatic beam was well simulated. All centrifugally formed square beams that make up the composite rahmen bridge were evaluated to secure sufficient load carrying capacity under the design live load, and structural reliability was proven by ensuring safety.

• The Korean Journal of Quaternary Research
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• v.20 no.2
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• pp.1-10
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• 2006

Flooding hazard caused by natural and artificial environmental changes is closely associated with change in river bed configuration. This study is aimed at explaining a river-bed change related to soil erosion in the Keum river basin using GIS and RS. The USLE was used to compute soil erosion rate on the basis of GIS. River-bed profiles stretching from Kongju to Ippo were measured to construct a 3D-geomorphological map. The river-bed change was also detected by remote sensing images using Landsat TM during the period of 1982 to 2000 for the Keum river. The result shows that USLE indicates a mean soil erosion rate of $1.8\;kg/m^2/year$, and a net increase of a river-bed change at a rate of $+5\;cm/m^2$/year in the Kangkyeong area. The change in river-bed is interpreted to have been caused by soil erosion in the downstream of the Keum river basin. In addition river-bed change mainly occurred on the downstream of the confluence where tributaries and the main channel meet. Other possible river-bed change is caused by a removal of fluvial sand aggregates, which might have resulted in a net decrease of exposed area of sediment distribution between 1991 and 1995, while a construction of underwater structures, including a bridge, a reclamation of sand bars for rice fields and dikes, resulted in an increase of the exposed area of river-bed due to sediment accumulation.

• Journal of environmental and Sanitary engineering
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• v.5 no.1
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• pp.1.1-14
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• 1990

This study was conducted to investigate the contents of heavy metals in soils of the Kumho river basin, by analyzing soils according to the distance from edge of the river and to the soil layers. The contents of heavy metals in soils showed highly in its downstream. Namely there was shown a remarkably high contents of these heavy metals in the Kum-ho bridge areas where Kongdan stream joins Dalseo stream, such as 39.52ppm for zinc, 35.92ppm for copper, 97.90ppm for iron, 102.45ppm for manganese, 13.92ppm for lead, respectively, and 0.48ppm for cadmium. However, the heavy metals contents in soils around Kangchang bridge tended to gradually decrease in its contents, probably because its main soils consisting of sand. Based on their soil layers, the average contents of these heavy metals in the surface soils were higher than one of the subsurface soil. Its contents according to the distance from the river edge indicated some difference every individual area. Nevertheless, its contents showed lower contents in the area far away from the edge. And its contents tended to again increase in the outside bank. In addition, a remarkable positive correlation is shorten between individual heavy metals, except correlation between iron and lead. Also cadmium just shows reverses correlation in the statistics. With respect to comparison between soil layers, there was a remarkable positive correlation between surface layers and subsurface layers. Considering the above results, it seems that the pollution of river bed's soil is in proportion to it of stream.

• 한국해양학회지
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• v.26 no.1
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• pp.13-23
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• 1991

For the purpose of examining the depositional sedimentary environments in the Han River estuary and around the Kyunggi Bay posterior to the Han river's developments, a hydrological and sedimen-tological survey was carried out. According to the hydrological and sedimentological conditions, the studied area can be divided into 3 depositional sedimentary environments: Fluvial, Estuarine and coastal-Bay. Posterior to the Han river's developments, however, the alterations of hydrodynamic condition in the Han river have caused a substantial change of the sedimentary environments in the lower Han river and its estuary. That is, the contents of total suspended sediment anterior to the Developments decreased from 37mg/l (in the lower Han River) and 500-1750 mg/l (at the Kanghwa Bridge) to 18 mg/l and 208-1142 mg/l posterior to the developments. these changes seem to have caused the siltation near the sin-gok Underwater Dam. Thus the characters of the boundary condition between the fluvial and the estuarine environments have rapidly changed. It is considered that these changes result mainly from the construction of the two underwater dams for the maintenance of the water level of the Han river. As the estuary is a transition zone between land and sea, these changes in the Han River estuary might affect the sedimentary environments around the Kyunggi Bay. In order to verify the effects of these changes, it is necessary that a detailed survey be carried out around the Han River estuary including the Imjin and Yesong River estuaries.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.8
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• pp.117-128
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• 2018

The central of Ulsan was formed and has been developed in alluvial plains the Riverfront of Taehwa River and Dongcheon River Fortresses including Gyebyeonseong of the late Silla, Chisoseong of the Goryeo, Ulsan Gyeonsangjwabyeongyeongseong, Ulsaneupseong, Ulsanwaeseong and Yeompoyeongseong as well as Gugangseowon and Old Ulsanhyanggyo and other facilities well display such fact. In the southern areas of Taehwa River, Byeokpajeong of Samsan, Buddhist temples and pavilion architectures used to be located. In its upstream areas, Eonyangeupseong, Eonyanghyanggo, Banguseowon and Daegokcheon Petroglyph exist as well. As such, the Riverfront of Taehwa River are a central space where the civilization of Ulsan has grown and developed, and are regarded as a core scenic asset of Ulsan. However, the look and nature of Taehwa River changed significantly due to Ulsan irrigation project and the construction of modern bridges such as Ulsangyo and Ulsan railway bridge during the period of Japanese occupation. The old look of the area started to be ruined by water contaminations and developments of waterfront lands that resulted from the development of Ulsan Industrial Center in 1962. The water quality of Taehwa River has been improved as a result of allotting a huge budget and administrative powers before and after 1997, the year when Ulsan was elevated to a metropolitan city. However, the surrounding views around Taehwa River changed greatly due to various urban development projects including apartment complex constructions. This is because the development of the Riverfront started from a land utilization project, in which the construction of apartment complexes was included in the initial phase; as a result, the areas were changed to be private scenic assets for those apartments. Aware of such issue, this study aims to identify major scenic elements that were present in the period before such developments in the river's surrounding areas from literature and geography materials; and to reveal how various urban development projects that have been performed from the period of Japanese occupation have changed the scenic elements of Riverfront of Taehwa River. The purpose of this study is to identify qualitative and quantitative changes in scenic elements of the Riverfront of Taehwa River as well as the characteristics of the resulting changes in the surrounding scenery.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.224-228
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• 2004

In these days, as it frequently happens that water level in the river exceeds the design floods due to irregular heavy rainfall, so it is required, first of an, to manage with railroad bridge safely. Because train control criterion under heavy rainfall is still not prepared and automatic flood monitoring system for railroad bridges is not used, worry over invisible economic loss due to train passage delay is in existence. Therefore, it is important to secure the safety and detect the risk like turnover or failure of railroad bridges through systematic disaster prevention system. And the transition from conventional monitoring method to real time monitoring method supported by sensors and communication system with high technology is rapidly needed. This research is on developing the real time flood monitoring system which prevents railroad disasters in advance by detecting continuously the water level of railroad bridge through CCD camera and water level gauge.