• Title/Summary/Keyword: Concrete Structures

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A basic study on the creation of historic revolutionary sites in North Korea (북한의 혁명사적지 및 혁명전적지 형성에 관한 기초연구)

  • 김동찬;안봉원;서주환;김광래;김신원
    • Journal of the Korean Institute of Landscape Architecture
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    • v.23 no.4
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    • pp.61-80
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    • 1996
  • This research study presents historic revolutionary sites in North Korea. In this study, the creation of historic revolutionary sites in North Korea after the Liberation of Korea in 1945, as yet unpublished in the field of landscape architecture and urban planning, is investigated. For conducting this study, the method of true and urban planning, is investigated. For conducting this study, the method of archival research, in which regarding documents, plans and photographs are investigated, was used. This study covers notions, establishment, related laws and regulations, distribution and present status, developmental stages, concrete examples, and general characteristics, of historic revolutionary sites in North Korea. In North Korea, historic revolutionary sites mean all the places where revolutionary achievements of Kim, Ill-Sung and his family are reached. Those sites have been actively created for the purpose of the idolization of Kim, Ill-Sung since the 1960s. In recent years, the sites have been revobated and new places of this kind have been constructed, so that various idolization facilities and structures are now everywhere in North Korea. Historic revolutionary sites are mainly distributed now everywhere in North Korea. Historic revolutionary sites are mainly distributed now everywhere in North Korea. Historic revolutionary sites are mainly distributed in Pyungyang, the forest areas of Mt. Pakdu, the areas along the shore of the Tuman River and the Abrock River. In those sites, various historic revolutionary relics are preserved, and the statues of Kim, Ill-Sung, historic revolutionary monuments, revolutionary museums and other facilities are constructed. These places can not be regarded as planned spaces for people in true the meaning of place, and accordingly they must be reconstructed for people's use. They can be redeveloped as places of history, culture and deucation, theme parks, green open spaces, and sight-seeing facilities after unification of Korea. This study can be used as valuable information for further study especially for the reconstruction planning of the places in preparation for a probable unified Korea. For a profound study, North Korea must open broader and more accurately detailed documents, regarding historic revolutionary sites, to the outside world, and the South Korean Government must also have a sense of co-ownership of the information about North Korea rather than exclusive possession and restrictions. Ultimately, academic exchange between South and North Korea must be realized and on-the-spot surveys must be carried out so as to find a reasonable land use plan for the historic revolutionary sites for a future unified Korea.

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Study of Failure Mode and Static Behavior of Lightweight FRP Truss Bridge Deck System (복합재료 트러스 교량시스템의 정적거동 및 파괴모드에 관한 해석적 연구)

  • Jung, Woo-Young;Lee, Hyung-Kil
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.20 no.5
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    • pp.511-520
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    • 2007
  • There is a concern with worldwide deterioration of highway bridges, particularly reinforced concrete. The advantages of fibre reinforced plastic(FRP) composites over conventional materials motivate their use in highway bridges for replacement of structures. Recently, an FRP deck has been installed on a state highway, located in New York State, as an experimental project. In this paper, a systematic approach for analysis of this FRP deck bridge is presented. Multi-step linear numerical analyses have been performed using the finite element method to study the structural behavior and the possible failure mechanism of the FRP deck-superstructure system. Deck's self-weight and ply orientations at the interface between steel girders and FRP deck are considered in this study. From this research, the results of the numerical analyses were corroborated with field test results. Analytical results reveal several potential failure mechanism for the FRP deck and truss bridge system. The results presented in this study may be used to propose engineering design guideline for new and replacement FRP bridge deck structure.

The Evaluation on Applicability of Leakage-prevented Sealing Packer Out of Grouted Rockbolt Hole (록볼트 그라우팅 시 역류방지용 밀봉 패커의 적용성 평가)

  • Yang, Taeseon;Kim, Jichang;Jeong, Jongki;Yoo, Dongho;Choi, HakYun;Baek, Seungcheol
    • Journal of the Korean GEO-environmental Society
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    • v.17 no.11
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    • pp.15-21
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    • 2016
  • Nowadays, some studies have been performed for rockbolt method widely used in Korea. To make large slopes, tunnels or rock structures stable, supporting systems, such as anchor bolt, rock bolt which are developed recently, are commonly used. In this study, laboratory pullout tests were carried out to compare the characteristics of rock bolt that is most widely used with ones of rock bolt by newly developed circular model testers. Re-pullout test for the rock bolt in which loading and unloading cycles are repeated several times showed that the maximum pullout load is almost constant irrespective of the number of loading cycles, which may be due to no failure between rock bolt and filler that is filled with soils and concrete as a substitute. A development of rock bolt fillers as supporters using to protect people in tunnels and slopes is reviewed as a probable man-made hazard after excavation works. The functions of the grouted rock bolts associated with reinforcement effects also should be assessed in this study, which develop the sealing apparatus preventing from overflowing mortar out of a rock bolt hole for securing safety in the tunnel and slopes in order to secure stability named the sealing packer.

Resistance to Chloride Attack of FRP Hybrid Bar After Freezing and Thawing Action (동결융해 이후의 FRP Hybrid Bar의 부식 저항성)

  • Ryu, Hwa-Sung;Park, Ki-Tae;Yoon, Yong-Sik;Kwon, Seung-Jun
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.6 no.1
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    • pp.59-65
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    • 2018
  • RC(Reinforced Concrete) structures are exposed to various exterior conditions, and the performances of both chloride resistance and freezing/thawing action are evaluated for those exposed to corrosive environment-sea shore. Recently developed FRP Hybrid Bars which is coated with glass fiber and epoxy with core steel has an engineering advantage of higher Elasticity than FRP rod. In this work, corrosion resistance, weight loss, and bond strength are evaluated for the FRP Hybrid Bar tested through freezing/thawing action for 300cycles. The double coated FRP Hybrid Bar shows the least weight loss without defection due to freezing/thawing action. Bond strength in FRP Hybrid Bar increases to 120% of normal steel through torturity effect with Si-coating. Bond strength in normal steel shows 0.86~0.89times in 3-day corrosion acceleration and 0.35~0.38times in 5-day corrosion acceleration, however, that in FRP Hybrid Bar shows little changes in bond strength before and after freezing/thawing action.

Transverse Reinforcement for Circular Internally Confined Hollow RC column (원형 내부 구속 중공 RC 기둥의 심부 구속 횡방향 철근 연구)

  • Won, Deok Hee;Han, Taek Hee;Park, Woo Sun;Park, Jong Sub;Kang, Young Jong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.2
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    • pp.927-935
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    • 2013
  • Recently, bridge structures has progressed the researches about seismic performance by occurrence of earthquake increased compared with the past. In the substructure of bridge, confining transverse reinforcement has arranged in plastic hinge region to resist the lateral load which increased the lateral confining effect. Columns are increased the seismic performance through secure of the stiffness and ductility The design specification for arrangement of confining transverse reinforcement same specification of domestic and international that suggested to solid reinforced concrete column(RC). This design specification have limits for Internally Confined Hollow RC(ICH RC) column because of different the component and performance characteristics of column. In this paper suggested the modified equation for economics and rational design through investigation of displacement ductility when applied the existing specification at the steel composite hollow RC column.

Environmental Impact Assessment of Nuclear Power Plant Accident using Spatial Information Modeling: A Case Study of Chernobyl (공간정보 모델링을 이용한 원전 사고의 환경 영향 평가: 체르노빌 사례연구)

  • Lee, Sang-Won;Song, Ah-Ram;Park, No-Wook
    • Korean Journal of Remote Sensing
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    • v.28 no.1
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    • pp.129-143
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    • 2012
  • This paper demonstrates the effectiveness of advanced spatial modeling techniques for environmental monitoring and impact assessment through a case study of Chernobyl nuclear accident occurred in 1986. Land-cover types changed after the accident are analysed by a post classification comparison method using bi-temporal Landsat TM data acquired in 1986 and 1992 near the accident site. Spatial modeling including various kriging algorithms are also applied to analyze the relationships between Cesium concentrations in soil and thyroid cancer incidence rates in Belarus, which was greatly damaged by the accident. The change detection results clearly showed the decrease of croplands and the increase of abandoned lands, and concrete structures were newly built around the nuclear plant to prevent the spread of radioactive contamination. In Belarus, high Cesium concentrations were observed in southern areas with high thyroid cancer risk estimated by Poisson kriging. Geographically weighted regression, which could account for geographic variations of independent variables including Cesium concentrations and distances from the Chernobyl nuclear power plant, was applied to extract the relationships between the independent variables and the thyroid cancer risk. The estimated risk values showed a correlation coefficient value of 0.98 with respect to the thyroid cancer risk values, which implied that the thyroid cancer risk in Belarus was affected by the accident. In conclusion, it is expected that advanced spatial modeling techniques applied in this study would be useful for environmental impact assessment and public health research.

A Study for Improving in Greening System and Method to Revitalize Wall-planting (벽면녹화 활성화를 위한 제도적 개선방안 및 조성방향에 관한 연구)

  • Han, Seung-Ho;Kim, Sun-Hae
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.9 no.2
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    • pp.59-71
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    • 2006
  • Due to the rapid process of industrialization the cities of Korea confront changes of climate, destructions of the habitate and decrease of the green. Recently Seoul and other local governments have implemented policies and projects to improve the environmental surroundings. In reality, however, those policies and projects face difficulties in the course of implementation. The fact that there are no concrete regulations and specific legal procedures turns out to be one of the main difficulties. The aim of this study is to present specific plans and methods of wall-planting and to provide basic guidelines for the future direction of wall-planting and offer ideas of facilitating wall-planting. This study is based on questionnaires from specialists of landscape architecture through individual interviews and/or e-mails. The questionnaire is consisted of following 4 sections. 1. Show the experts current regulations and/or legal procedures and ask them improvements and suggestions. 2. Ask them choose matters of the highest priority by using Ricardo's diagram method. 3. Ask them to make a graded list in terms of the location and method of wall-planting. 4. Study the maketability of the wall-planting products currently in circulation. The city of Seoul and the Ministry of Environment recommend that trellis and/or planting inducement structures be installed on the building wall by regulation. The specialists responded to the questionnaire advocate that green wall without trellis should be allowed as green zone. Therefore regulations concerning the wall-planting should be determined specifically according to the characteristics of individual plants and walls. It has been urged that legal aid and social support must be reinforced to establish rules dealing with wall-planting. The respondents also point out that significant cutting down of the tax is far more effective in accelerating the wall-green instead of administrative support. The highest priority in terms of planting has been given to sound-proof wall, retaining wall and building wall. Concerning the maketability of the wall-planting products, panel products are recommended for early-planting and building planting. It has been suggested that the research and study of new materials and species be done in advance.

Developing An Extracting Method of Laminated Glass-Fiber for Waste FRP Boats Regenerating (폐FRP 선박의 재자원화를 위한 유리면포 추출장치 개발)

  • Yoon, Koo-Young
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.11 no.1
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    • pp.50-54
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    • 2008
  • There are several basic classes of recycling methods for FRP boats. The main one is 'Mechanical recycling' which involves shredding and grinding of the scrap FRP in a new product. That is one of the simpler and more technically proven methods. It recently has been reported that FRP can be recycled by separating into layers instead of crushing into powder. Many researchers should be more interested in these mechanical recycling for the eligibility. Nevertheless, because resins is very useful renewable energy, most of waste FRP regenerating methods depend on incineration (reclamation) or thermal recycling (pyrolysis). FRP is made up of laminated glass- fiber (roving cloth layer) which is also very unlikely to break into each layer. If there is an extracting method which is efficient and environment friendly removing glass fiber from waste FRP, it should also solve the another urgent problem. Laminated glass-fiber which is very limited renewable, is a serious barrier to wast FRP boat regenerating. This study is to propose a new extracting method which is efficient and environment friendly waste FRP regenerating system. And it should be applied to renewable energy applications with the waste resins of FRP. Also recycling glass fiber obtained by the separation of the roving layer from waste FRP will be consider to be useful for concrete products or structures.

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A Study on the Uplift Capacity of Cylindrical Concrete Foundations for Pipe-Framed Greenhouse (파이프 골조온실의 원주형 콘크리트 기초의 인발저항력에 관한 연구)

  • ;;;;Shino Kazuo
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.40 no.4
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    • pp.109-119
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    • 1998
  • Recently pipe-framed greenhouses are widely constructed on domestic farm area. These greenhouses are extremely light-weighted structures and so are easily damaged under strong wind due to the lack of uplift resistance of foundation piles. This experiment was carried out by laboratory soil tank to investigate the displacement be haviors of cylindrical pile foundations according to the uplift loads. Tested soils were sampled from two different greenhouse areas. The treatment for each soil type are consisted of 3 different soil moisture conditions, 2 different soil depths, and 3 different soil compaction ratios. Each test was designed to be repeated 2 times and additional tests were carried out when needed. The results are summarized as follows : 1. When the soil moisture content are low and/or pile foundations are buried relatively shallow, ultimate uplift capacity of foundation soil was generated just after begining of uplift displacement. But under the high moisture conditions and/or deeply buried depth, ultimate up-lift capacity of foundation soil was generated before the begining of uplift displacement. 2. For the case of soil S$_1$, the ultimate uplift capacity of piles depending on moisture contents was found to be highest in optimum moisture condition and in the order of air dryed and saturated moisture contents. But for the case of soil S$_2$, the ultimate uplift capacity was found to be highest in optimum moisture condition and in the order of saturated and air dryed moisture contents. 3. Ultimate uplift capacities are varied depending on the pile foundation soil moisture conditions. Under the conditions of optimum soil moisture contents with 60cm soil depth, the ultimate uplift capacity of pile foundation in compaction ratio of 80%, 85%, and 90% for soil 51 are 76kg, 115kg, and 155kg, respectively, and for soil S$_2$are 36kg, 60kg, and 92kg, respectively. But considering that typical greenhouse uplift failure be occurred under saturnted soil moisture content which prevails during high wind storm accompanying heavy rain, pile foundation is required to be designed under the soil condition of saturated moisture content. 4. Approximated safe wind velosities estimated for soil sample S$_1$and S$_2$are 32.92m/s and 26.58m/s respectively under the optimum soil condition of 90% compaction ratio and optimum moisture content. But considering the uplift failure pattern under saturated moisture contents which are typical situations of high wind accompanying heavy rain, the safe wind velosities for soil sample S$_1$and S$_2$are not any higher than 20.33m/s and 22.69m/s respectively.

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An Experimental Study on the Behavior of Curved Panel Parts Using Composite Materials (복합소재를 활용한 곡면 패널의 부재단위 성능 평가)

  • Park, Hee Beom;Park, Jong-Sup;Kang, Jae-Yoon;Jung, Woo-Tai
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.7
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    • pp.474-480
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    • 2018
  • FRP is a new material that is lightweight, has high strength and high durability, and is emerging as a third construction material in many countries. The composite material panel targeted in this study was a curved member and is the most frequently used arch-shaped member of a structures, such as tunnels. Composite curved panels can be produced in high quality and large quantities through automation operations. On the other hand, the frequency of application is low, and the design criteria and experimental data are lacking. Therefore, this study examined the mechanical performance of the member unit first to verify its performance as structural members of the FRP curved panel. For this purpose, tensile, compression, and connection performance tests were carried out. The tensile tests showed greater tensile strength of specimens with larger curvature, and the compression tests showed that the composite section of a composite material has greater compressive strength than the concrete section. Finally, the test of the performance of the connection showed that the attachment performance of the connection was more than equal to that of the FRP composite material panel.