• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.721-724
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• 2008

The present study was to develop a dry PFB method similar to the existing gypsum board construction method in order to apply the existing wet PFB method that uses fire.resistant adhesive. It was found that the existing wet method can produce concrete compressive strength of 80MPa and fire resistance of 3 hours with 30mm PF boards. The goal of development in this study was fire resistance of 3 hours through dry construction of 15mm fire resistant boards. The results of fire resistance test showed an increase in thermal durability and thermal strain. It is believed that inorganic fiber reduces thermal strain, and lowers heat insulation performance by 15% or less. This suggests that heat insulation performance was improved by the change in the inner composition of PF board resulting from the adjustment of Al:Si mol ratio, high temperature molding, and dry curing. According to the results of fire resistance test, when the dry PF method was applied, the temperature of the main reinforcing bar was 116$^\circ$C in 15mm, 103.8$^\circ$C in 20mm, and 94$^\circ$C in 25mm, and these results satisfied the current standards for fire resistance control presented by the Ministry of Land, Transport and Maritime Affairs. When a 3 hour fire resistance test was performed and the external properties of the specimen were examined, the outermost gypsum board hardly remained and internal PF board maintained its form without thermal strain.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.4
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• pp.657-669
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• 2018

In recent years, the development of complex urban areas has become saturated and much attention has been focused on the development of underground space, and deep excavation is frequently performed in order to increase the utilization of underground space due to the enlargement of buildings and the high rise of buildings. Therefore, in this study, we tried to understand the behavior of the braced wall and the behavior of the tunnel adjacent to the wall according to the stiffness of the wall and the distance between the tunnel and wall. As a result of the study, the deformation of the braced wall tended to decrease with increasing the stiffness of the wall, and the axial force acting on the struts was also different according to the stiffness of braced wall. When the stiffness of the braced wall is small (2 mm), the point at which the axial force of the braces maximizes is near 0.3H of the wall. When the stiffness of the braced wall is large (5 mm), the axial force is maximum at around 0.7H of the wall. Also, the tunnel convergence occurred more clearly when the separation distance from the braced wall was closer, the stiffness of the wall was smaller, and the tunnel convergence was concentrated to the lower right part. The ground settlement due to the excavation of the ground tended to decrease as the distance between tunnel and braced wall was closer to that of the tunnel, which is considered to be influenced by the stiffness of the tunnel.

• Journal of the Korea institute for structural maintenance and inspection
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• v.14 no.2
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• pp.106-112
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• 2010

Due to the improvement and stabilization of the social environment, construction market in the urban region is under shrinking. According, researches to lengthen the service life of the existing building structures are under the way through the remodeling or maintenance of deteriorated structures other than the new constructions. Similar situations are widely discussed in the domestic building construction market and the social importance of the remodeling of the existing building structures is increased. Although the structural stability of the building is uncertain due to the frequent repairing and structural changing, the remodeling works are usually conducted. In general, documents such as drawings and calculations for the design of the deteriorated structure to be remodeled are not kept. Accident at the remodeling site frequently occur because of the lack of thorough understanding of changed situations such as loadings, loading paths, changing of the mechanical properties of material, etc. In this paper, using the finite element analysis method, we investigated the structural behaviors of slab in the remodeling building and the results are applied to remodeling construction, and the appropriateness of the remodeling works are evaluated.

• Journal of Environmental Impact Assessment
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• v.29 no.1
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• pp.1-7
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• 2020

This study aims to evaluate the effect of artificial facilities constructed afterthe release of the civilian controlled zone (CCZ) in Cheorwon on the inhabitation of cranes. The study site was released from the CCZ in 2012, and several barns have been built since 2017. The average number of Red-crowned Cranes was 9.3±4.3 individuals (±Standard Deviation) in the period before the release of the CCZ from 2009 to 2012, and it decreased by ca. one third of Red-crowned Crane's average individuals were showing 3.5±0.5 individuals after release. The average number of White-naped Cranes also appeared to be decreased by ca. 90% from 63.3±24.6 to 6.0±6.0 individuals. This results suggest that the construction of greenhouses and barns after the releasing of the CCZ affected the decrease of the population of these two crane species. In the case of Red-crowned Crane, the core area tended to move away from the area where barns were built. However, the distribution range of Red-crowned Cranes did not change significantly we expected because the study area was not their favorite place since 2012 when the area was released from the CCZ. The density of the White-naped Crane was relatively high even in the area where greenhouses were built, but after 2017 when the barn was built intensively, core habitat of crane became shrink and fragmented. These results suggest that both Red-crowned Cranes and White-naped Cranes response sensitively against habitat change due to the construction of barns. Since the release of the CCZ, the construction of the greenhouse has been influenced on the distribution of cranes, but subsequently, the construction of the barn seems to have caused a bigger change in their core habitat because the passage of people to barns is more frequent than the greenhouses.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.4
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• pp.50-58
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• 2014

Due to the cost burden of new construction, the necessity of repair and retrofitting of aged structures is sharply increasing as the domain of repair and retrofitting construction is expanding. Because of the necessity, new technologies for repair and retrofitting are continuously studied in Korea and foreign countries. Steel adhesive method, fiber reinforced plastic (FRP) surface adhesive method, and external prestressing method are used to perform the repair and retrofitting works in Korea. In order to consider a repair method using steel mesh reinforced cement mortar (SMCM), 3-point flexural member test was conducted considering repair area and layer number of SMCM. Five types of specimens including ordinary reinforced concrete (RC) specimen with dimensions of $1400{\times}500{\times}200$ (mm) were cast for testing the deflection measurement, a LVDT was installed at the top center of the specimens. Also, a steel strain gauge and a concrete strain gauge were placed at the center of the specimens. A steel strain gauge was also installed on the shear reinforcement. The 3 point flexural member test results showed that the maximum load of SMCM reinforced specimen was higher than that of basic RC specimen in all of the load-displacement curves. Also, the results showed that, when the whole lower part of the basic RC specimen was reinforced, the maximum load and strain were 1.18 and 1.37 times higher than that of the basic RC specimen, respectively. Each specimen showed a slightly different failure behavior where the difference of the results was caused by the difference in the adhesive level between SMCM and RC. Particularly, in SM-B1 specimen, SMCM spalled off during the experiment. This failure behavior showed that the adhesive performance for RC must be improved in order to utilize SMCM as repair and retrofitting material.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.36 no.1
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• pp.120-128
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• 2018

The purpose of this study is to establish basic data for the continuous protection management policy of domestic natural world heritage and mixed world heritage, and to examine the present situation and characteristics of the protection management according to the World Heritage Convention on the World Heritage listed Huangshan. The results of this study are as follows. First, Huangshan began to be protected by the establishment of the Huangshan Construction Committee in 1933, and after the designation of national park in 1982, laws and regulations were established in the central ministries, And various projects related to utilization have been implemented. Secondly, the establishment of the boundary for protection was actively intervened by the central government, such as the reorganization of the boundary of Huangshan through the administrative district plan. In order to protect the ecological and landscape value as well as the cultural factor, And designated a heritage designated area. Third, the protection management of Huangshan was divided into four major stages. The first phase was divided into the period when administrative measures were taken to manage the protection of Huangshan. The second phase was designated as a national park in Huangshan. The third period was the time of the protection-oriented project according to the recommendation of the international organizations after the World Heritage listed. The fourth period was the expansion of the tourism industry for the continuous use of protection of Huangshan city, My preservation business was being implemented. Fourth, Huangshan is managed by the central government and the city government. Huangshan, which is a mixed heritage, is managed jointly by the Ministry of Cultural Heritage Administration and the Ministry of Natural Heritage Administration. The protection and management of Huangshan promoted the efficiency and expertise of the heritage-related work through the establishment of the administrative unit-specific management system, and the local governments were entrusted with the authority to implement the protection management policies that meet local characteristics. Fifth, the preservation area of Huangshan has been destroyed by the development policy centered on the mountain. In addition, according to the operation of accommodation facilities, there are problems such as sewage, garbage disposal, and environmental pollution caused by tourists, and the damage caused by pests and diseases in planted plantations around the area and changes in ecosystem due to the composition of cable cars. Sixth, for the continuous protection of Huangshan, strict regulations on new construction, extension and management of accommodation are required, and it is necessary to install facilities to limit and control the number of visitors.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.2
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• pp.19-30
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• 2012

Due to the fact that the social environment is improved and the urban development is stabilized, the demand of new construction of apartment becomes slowdown. Accordingly, there are many researches to lengthen the service life of the existing apartment through the remodeling and its importance is continuously rising. However, reliable design specifications and guidelines for the design of remodeling with partial demolition are not provided yet in Korea. Specially, in the apartment remodeling, slab collapse accidents take major portion in all accidents that reported by Korean Government. It is very important to prevent intial crack of slab because intial crack could cause severe accident like collapse of all structure in a short period of time. The purpose of this study is to develop structural guidelines that could guarantee the structural safety and serviceability of slab structure and could be adopted in Korean remodeling with partial demolition. There are mainly two components to determine structural behavior of slab structure. One is the shape of slab structure and the other is load which is resisted by the slab structure. In this study, the weight per unit volume of concrete debris and concrete strength are estimated through the analysis of previous researches to recognize the relationship between the shape of slab and load that loaded on the slab. Accordingly, approximately 300 pieces of floor plan are collected and analyzed. The finite element analysis is conducted using these analyzed and estimated results. From the finite element analysis results, the limited stacking height of debris is suggested and the stacking method is also discussed. In addition, to find the relationship between movement of demolition equipment and structural behavior of slab, the static and dynamic loading tests are conducted. From the results of loading tests, the impact factor which will be considered in the remodeling design could be estimated.

• Korean Journal of Environment and Ecology
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• v.33 no.3
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• pp.303-320
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• 2019

Plants interact with various biotic and abiotic environmental factors. It requires much information to understand the traits of a plant species. A shortage of information would restrict the assessment, especially in the evaluation of what kind of factors influence a plant species to face extinction. Polygonatum stenophyllum Maxim. is one of the northern plants of which Korea is the southern distribution edge. The Korean Ministry of Environment had designated it to be the endangered species until December 2015. Although it is comparatively widespread, and a large population has recently been reported, it is assessed to be vulnerable due to the low population genetic diversity. This study evaluated the current distribution of Polygonatum stenophyllum Maxim. We investigated the vegetational environment, population structures, phenology, soil environment, and self-incompatibility based on the results. Lastly, we evaluated the current threats observed in the habitats. The habitats tended to be located in the areas where the masses at the edge of the stream accumulated except for those that were located on slopes of some mountainous areas. Most of them showed a stable population structure and had re-established or recruited seedlings. Polygonatum stenophyllum Maxim. had the difference in time when the shoots appeared above the ground depending on the depth of the rhizome located in the underground. In particular, the seedlings and juveniles had their rhizome located shallow in the soil. Visits by pollinator insects and success in pollination were crucial factors for bearing of fruits by Polygonatum stenophyllum Maxim. The threats observed in the habitat of Polygonatum stenophyllum Maxim. included the expansion of cultivated land, construction of new buildings, and construction of river banks and roads. Despite such observed risk factors, it is not likely that there would be rapid population reduction or extinction because of its widespread distribution with the total population of more than 2.7 million individuals and the new populations established by the re-colonization.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.40 no.1
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• pp.65-73
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• 2022

This paper analyzed the characteristics of ancient villages in Hongcun and the method of resetting the preservation area for the preservation of the changed historical and cultural space in Hongcun through the process of change. To this end, the current status of preservation areas and utilization areas in the village was identified through ancient documents, old paintings, policy materials, and interviews related to the village, and through this, the problem of resetting the preservation area was examined. As a result, the following conclusions were drawn. First, Hongcun is a village built under the influence of Confucianism, Buddhism, and Taoism, and the spatial organization was created according to the hierarchy of Confucianism. As a result, it was possible to inherit and preserve the heritage of ancestors even though the central government did not preserve it. Second, the concept of preservation in a limited sense has been applied as Hongcun has been recognized as a cultural heritage that has been passed down since ancient times, but the Great Leap Forward and the Cultural Revolution brought about changes in the village space. Since then, ancient buildings, water systems, and forests have been preserved through regulations on new construction and expansion of a building with the Hongchon preservation plan, but the development within the preservation area is underway due to changes in the lives of original inhabitants, which were followed by continued development pressure and reform and opening. Third, the original inhabitant of ancient villages had a high perception of the value of the heritage, but they demanded the preparation of measures to improve living conditions and create profits, and the active use of villages for this. Fourth, the forest consisting of old trees is being restored, but the gardens in the old house are showing a phenomenon that the garden space is reduced or transformed for use. The bridges and parking lots were newly built in the southern area, which was extended from the western area, the original entrance to the ancient village, resulting in changes in the existing entrance. This was found to be the primary cause of the spatial change of the ancient village, as the road system was modified to make it convenient for tourists to enter and exit. Fifth, the existing preservation area should be reset and preserved by resetting the preservation route centered on Wolso(half Moon Pool), while the surrounding area should be set as a direct and indirect experience space, and according to the hierarchy of each space, the utilization should proceed while the preservation is carried out by crossing the preservation and the utilization.

• Korean Journal of Environment and Ecology
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• v.38 no.4
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• pp.416-425
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• 2024

This study aims to analyze the changes in land prices and building construction activities before and after exclusion from park district as results of natural park re-planning. Seoraksan National Park, Namhansanseong Provincial Park, and Cheonmasan County Park were selected as study areas, and prices and construction activities were compared between areas remaining in and areas excluded from park districts for ten years after park re-planning. Land prices increased in all three study parks. The largest difference in land prices between remaining and excluded areas occurred in Cheonmasan City Park. Land price increased more in excluded than remaining areas in Seoraksan National Park. Unlike these two parks, the changes in land prices were not much different between remaining and excluded areas in Namhansanseong Provincial Park, which can be attributed to the facts that 1) provincial parks were already developed to certain level even before the exclusion due to its less stringent land use regulation than national parks, and 2) that Namhansanseong Provincial Park was also designated as Restricted Development Zone that has similar land use regulation level to natural parks. Comparison between building density measures before and after exclusion shows that development density generally increased after the exclusion. Building heights mostly increased during 10 years after the exclusion. Building to land ratios and floor area ratios also increased. However, building to land ratios and floor area ratios increased only slightly in Namhansanseong Provincial Park and Cheonmasan City Park, suggesting that in provincial and city parks, land development already occurred as a result of less stringent land use regulation. In conclusion, a national park system significantly restricts property right in natural parks, especially in national parks, which make it difficult to expand existing natural parks and/or establish new natural parks. A remedy for resolving problems related to private lands, such as increasing budget for purchasing private lands and introducing park facilities for local community is urgently required.