• Proceeding of Spring/Autumn Annual Conference of KHA
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• 2004.11a
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• pp.257-262
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• 2004

The very problem we are to touch in this study is that our own types of urban housing complex are isolated from the existing residential environment. The closed and self-completing structures of past urban housing complexes didn't develop the communal spirit and it has increased anti-city trends. With all that, this study intends to provide some materials to reform our urban housing environment through analyzing former European examples on the basis of the development of our own urban housing types which will correspond with existing urban structure and urban tissue.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.249-256
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• 2006

New infrastructures and buildings are being constructed increasingly in congested urban areas, and excavation-induced ground movements often cause distortion and damage to adjacent buildings. Protection of adjacent structures occupies a major part of the cost, schedule and third-party impacts of urban development. To limit damage or mitigate their effects on nearby structures, it is highly important to understand the whole mechanism from excavation to building damage, and to estimate building damage reliably before excavation and provide appropriate measures. This paper investigates the effects of excavation-induced ground movements on nearby structures, considering soil-structure interactions for ground and structures, and a building damage criterion, which is based on the state of strain, is proposed. The criterion is compared with other existing damage estimation criteria and a procedure is finally provided for estimating building damage due to excavation-induced ground movements.

• Journal of the Korean Institute of Landscape Architecture
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• v.28 no.6
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• pp.1-15
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• 2001

The purpose of this study is to figure out the structural characteristics of urban plant community and suggest restoration model of Quercus mongolica in the case of Korean national Capital Region. The investigation areas were selected from urban area of Mt. Nam at Chung-Gu, suburban areas of Mt. Bong at Eunpyoung-GU, Mt. Sungju at Buchon City and non-urban areas of Mt. Suri at Kunpu City and Mt. Chonma t namyangju-City. After the main study field had been classified into the evaluation of the ecological characteristics and the modeling of the vegetation. We analyzed to evaluate the ecological characteristics of the forest structure -- successional stage, naturalness, multi-layer structure of the forest and species diversity, and the plant community structures. We have proposed vegetation restoration model based on the selection of proper plants, the number of individuals, diameter short area of breast height, the shortest distance between plants in non-urban area. As for successional stage, It was judged that the ecological succession may not be followed like the present stage of the surveyed areas in urban, suburban and non-ruban areas. As for the retention of naturalness and multi-layer structures of vegetation, In Quercus mongolica community, Robinia pseudo-acacia and Ailanthus altissima occurred in each layers at Mt. Nam, Mt. Bong and Mt. Sungju, and Eupatorium rugosum occurred in herbaceous layer at Mt. Nam. Consequently, the ecological restoration plan following the structure of the vegetation in Mt. Chonma seemed to be advisable in Q. mongolica community, there were less number of species and individuals in urban areas than those of non-urban areas. Planting of trees following the simulated native plant community of non-urban areas seemed to be required to promote the plants in urban areas. Considering the number of individuals up to three layers in each 400$m^2$ area, it was composed of twenty nine in canopy layer, forth nine in understory layer, 367 in shrub layer and 33.7% herbaceous ground cover in the Q.mongolica community. The suggested restoration model in this study is nan applicable model for the introduction in the cities, and this study shows that continuous experiments and field investigation on this model should be performed in the future.

• Fire Science and Engineering
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• v.25 no.6
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• pp.1-7
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• 2011

As population grows and urban facilities are concentrated in specific areas due to recent urbanization and industrialization, cities have structures vulnerable to both natural and man-made disasters. Most of these structures, whether buildings or residential houses, are left in a defenseless state if not given the appropriate check-up before they are built. The process of rapid urbanization without establishing the proper urban fire risk assessment will surely lead to disasters. This phenomenon occurred during the process of rapid urbanization and maybe said the result of chaotic urban expansion where modern urban infrastructure is not yet equipped in the city. Under the said circumstances, propagation processes of Korean urban fire cases were investigated to establish fire risk assessment system. Moreover, this paper explains the experiment performed for establishing urban risk assessment model. The said experiment was conducted using the new urban fire risk assessment model.

• Proceedings of the Korean Geotechical Society Conference
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• 1990.10a
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• pp.87-96
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• 1990

Even though the number of construction cases of temporary retaining structures in urban area are increasing, there still are many problems to be solved in design and construction of temporary retaining structures. In this paper the current design methods are reviewed and their problems are analyzed. Some critical mistakes made by site technicians and engineers are also discussed.

• Smart Structures and Systems
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• v.21 no.5
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• pp.561-569
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• 2018

Ground vibration is one of the most undesirable effects induced by blast operation in mountain tunnels, which could cause negative impacts on the residents living nearby and adjacent structures. The ground vibration effects can be well represented by peak particle velocity (PPV) and corner frequency ($f_c$) on the ground. In this research, the PPV and the corner frequency of the mountain surface above the large-span tunnel of the new Badaling tunnel are observed by using the microseismic monitoring technique. A total of 53 sets of monitoring results caused by the blast inside tunnel are recorded. It is found that the measured values of PPV are lower than the allowable value. The measured values of corner frequency are greater than the natural frequencies of the Great Wall, which will not produce resonant vibration of the Great Wall. The vibration effects of associated parameters on the PPV and corner frequency which include blast charge, rock mass condition, and distance from the blast point to mountain surface, are studied by regression analysis. Empirical formulas are proposed to predict the PPV and the corner frequency of the Great Wall and surface structures due to blast, which can be used to determine the suitable blast charge inside the tunnel.

• Journal of the Korean Institute of Landscape Architecture
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• v.32 no.5
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• pp.102-118
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• 2004

The purpose of this study was to propose an ecological management plan by the comprehensive analysis of biotope structures on Namsan Urban Natural Park in Seoul. Classified by actual vegetation, structure of layer and vegetation damage, biotope structures were composed of forest area, compact management area, herb area, cultivated area and non-ecology(urban) area. Succession had seened to stop in the Native forest. Artifical forest was divided into two types. The first, upper layer, was too dense to accommodate lower layer plants, the other case was the appearance of Quercus spp. and the first stage plants of succession following the declination of the upper layer plants. The soil pH of Nam-san Urban Park was 4.21∼4.51, which meant the soil was becoming acid. As the result of acidity, leaching of available nutrition(K/sup +/, NH₄/sup +/, Ca/sup ++/ etc.) was immediately influenced by the natural ecosystem, influence of acid rain was disturbed to becoming organic matter which was use to plants. In the case of a biotope structure management plan, the urban area was prohibited to spread outside. Cultivated and herb area was regenerated to natural forest. In the forest area, the compact management area was maintained with its present condition, and then it is desirable to make a preservation area and to plant shrubs. Planted Pinus densiflora Community was needed to eliminate competitive species of canopy layer, and plant shrubs. Management of deciduous broad-leaved Comm. was maintained in its present conditionand it is desirable to raise the diversity of the understory and shrub layer. The management of the artifical forest seems to be suitable for Q. spp. community. The care of naturalized plants prevents the expansion and restores the structure of wild plants. The soil management was a marked restoration soil ecosystem in order to prevent soil acid and drying.

• Journal of Mechanical Science and Technology
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• v.20 no.9
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• pp.1346-1354
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• 2006

Excessive acceleration experienced at the top floors in a building during wind storms affect the serviceability of the building with respect to occupant comfort and discomfort. Tuned liquid damper (TLD) and multiple tuned liquid damper (MTLD), which are passive control devices consisting of a rigid tank filled with liquid, are used to suppress vibration of structures. These TLD and MTLD offer several potential advantages-low costs, easy installation in existing structures and effectiveness even for small-amplitude vibrations. This study carries out a theoretical estimation of the most effective damping ratios that can be achieved by TLD and MTLD. Damping by TLD an MTLD reduced the frequency response of high-rise buildings by approximately 40% in urban and suburban areas.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.1087-1094
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• 2010

With recent growth of population and industry, urban development grows into grand scheme of excavation and construction in urban area. As the development progress advanced, the developments get large and deepen. With a progress of technology development in geotechnical engineering in Korea, most our grand scheme of projects follows great progress. On the other hand, some excavation in construction site caused direct or indirect event that affects the adjacent or surrounding structures by excavation from time to time. This event usually happens around residential and commercial area where underground tunnel, subway station, commercial building, and high-rises excavation site is, could lead great damage on economy as well as personal injury or human casualties. In order to prevent this event, the study has to be done with analysis on various events of excavation and its cause. In this paper, the research has collected the various excavation events and their causes to analyze on each site and event to define emphasis on surrounding environment.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.41-46
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• 2002

Recently, the design and construction of massive concrete structures are increased, But, the temperature rise within a large concrete mass makes the construction of massive concrete structures be very difficult. Therefore, various techniques of the thermal stress control of the mass concrete have been widely used. One of them is pipe-cooling which reduces the temperature of concrete with flowing water. It was shown to be possible to construct the massive concrete foundation of urban bridge successfully by application of pipe-cooling system with steel pipe and water circulation. It was also found to expected to make it possible to reduce the probability of thermal crack development in a massive concrete foundation of urban bridge by pipe-cooling system.