• Steel and Composite Structures
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• v.13 no.1
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• pp.15-33
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• 2012

For an axially loaded box-shaped member, the width-to-thickness ratio of the plate elements preferably should not be greater than 40 for Q235 steel grades in accordance with the Chinese code GB50017-2003. However, in practical engineering the plate width-to-thickness ratio is up to 120, much more than the limiting value. In this paper, a 3D nonlinear finite element model is developed that accounts for both geometrical imperfections and residual stresses and the ultimate capacity of welded built-up box columns, with larger width-to-thickness ratios of 60, 70, 80, and 100, is simulated. At the same time, the interaction buckling strength of these members is determined using the effective width method recommended in the Chinese code GB50018-2002, Eurocode 3 EN1993-1 and American standard ANSI/AISC 360-10 and the direct strength method developed in recent years. The studies show that the finite element model proposed can simulate the behavior of nonlinear buckling of axially loaded box-shaped members very well. The width-to-thickness ratio of the plate elements in welded box section columns can be enlarged up to 100 for Q235 steel grades. Good agreements are observed between the results obtained from the FEM and direct strength method. The modified direct strength method provides a better estimation of the column strength compared to the direct strength method over the full range of plate width-to-thickness ratio. The Chinese code and Eurocode 3 are overly conservative prediction of column capacity while the American standard provides a better prediction and is slightly conservative for b/t = 60. Therefore, it is suggested that the modified direct strength method should be adopted when revising the Chinese code.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.3
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• pp.205-211
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• 2014

Interests on energy saving devices (ESDs) have been increased with the concern of the energy efficiency design index (EEDI) developed by the international maritime organization (IMO). To study the influence of ESDs, KVLCC2 with energy saving pre-swirl stator (PSS) was selected. To validate the computations, computed nominal wake of the model scale ship was compared with the experimental data, and the numerical uncertainty assessment was done for the full scale ship computations. The PSS changed rotational flow, which was assistant to the propeller thrust for the model and full scale ships. Performances of the full scale ships were predicted by ITTC methods, and new prediction method was proposed.

• The Korean Journal of Archival Studies
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• no.49
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• pp.77-119
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• 2016

A modern architectural building is a cultural heritage, which is also part of our history until the present. Documentation is thus considered an irreplaceable method to preserve our cultural heritage as it may be the last resort of preservation. The study analyzed the Historic American Buildings Survey (HABS) on the Heritage Documentation Programs of the National Park Service. Based on the analysis of the comparison and documentation of the modern architectural building implemented by the Cultural Heritage Administration, the study suggested improvement plans from three different perspectives. First, specifically detailed regulations of the legal system are supposed to be used for the implementation of the documentation of modern architectural buildings. Second, it is suggested that a general plan for continuous documentation be made. Last, by setting up a collection method, an information service needs to be provided for the public.

• Journal of the Korean Institute of Landscape Architecture
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• v.47 no.3
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• pp.49-59
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• 2019

This paper examines the background and content of Thomas Jefferson's botanical garden plan for the University of Virginia. When Jefferson promoted the establishment of a botanical garden, European botanical gardens were evolving from physic gardens, and American botanical gardens were in their infancy. Accordingly, this paper compares the Botanical Garden Plan for the University of Virginia with contemporary botanical gardens. This is examined by outlining the trends of botanical gardens in Europe and the United States around the nineteenth century, analyzing their function and spatial structure. Also, Jefferson's perspective on botany, his plan, and botanical gardens are reviewed. This study found that Jefferson's project had its background in the social recognition of the importance of botany as a practical science, advancing the national economy, which was a prominent goal in late eighteenth-century Europe, and in developing networks of exchanging plants and information concerning botany and botanical gardens. Based on the botanist Correia's opinion on the role of a public botanical garden, the Botanical Garden Plan for the University of Virginia was developed by Jefferson as an action plan, including its site creation, space organization, and supplying of plants. Compared to the other contemporary botanical gardens, the University of Virginia's Botanical Garden Plan has the following characteristics. First, like European gardens in the late eighteenth century, it evolved from being a physic garden to a botanical one. As such, it emphasized botanical research and education over medicine, creating a tree garden and a plant garden. Second, it differed from many European and American botanical gardens in that it rejected decorative elements, refused to install a greenhouse, and attempted to spread practical overseas plants suitable to the local climate. This study contributes to broadening the history of botanical gardens at the turn of the nineteenth century.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.36 no.2
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• pp.61-67
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• 2018

Jens Jensen was an American landscape architect and early conservationist who pioneered a unique naturalistic landscape style. The purpose of the present study is to study Jensen's life, careers, design philosophy, and his contributions to the history of landscape architecture. Inspired by nature, Jensen worked closely with native plants, local materials, curvilineal and circular forms, and native scenery. His pioneering work in the Chicago's West Parks, including the design of Columbus Park and Humboldt, Garfield and Douglas Parks, was informed by his philosophical belief in the humanizing power of parks. In summary, first, Jensen played a prominent role in the creation of a unique native landscape style respecting regional landscape. Second, as a devoted conservationist and educator he organized conservation movements preserving landscape heritage and founded a education institution. Third, as a social reformer he emphasized the value of parks and nearby nature for urban citizens and children. Jensen's visions and philosophies have influenced on recent naturalistic landscape style and conservation efforts to preserve cultural landscape and natural environment.

• Journal of the Korean Institute of Landscape Architecture
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• v.40 no.6
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• pp.98-111
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• 2012

This study found the possibility of using cemeteries within the locality as field trip destination. A comparison between Korea and the United States of America's active progress has derived the difference and the implications. Therefore, this article found that the cemetery has sufficient resources based on experience-learning place within the community. Therefore, when the active educational program was developed; it gained more abundant resources for education, as well as provided more different educational opportunities for the students than now. As the result of comparison, the reason why the educational program is actively progressing in the American cemeteries is that a beautiful and fresh environment has been built up such as a park or garden in a cemetery and has been preserved as a healthy forest ecosystem. Furthermore, it is because they actively used the cemetery within a community as the subject. If our cemetery can be renovated and the funeral culture can be changed to break down the image of an avoidable unpleasant facility, it would play a role as a field for learning experience.

• Journal of Environmental Science International
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• v.28 no.12
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• pp.1147-1156
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• 2019

The purpose of this study was to analyze examples of green infrastructure presented by the American Society of Landscape Architects as a part of basic research to assess hub green spaces in cities. With the specific goal of green infrasturcture in mind, the study samples were classified according to their purpose: 'humanities', 'hydrology', 'ecology', and 'environment'. Based on this we assessed the elements of planning for the target sites and obtained the following results. With regard to the aspect of humanities, planning urban hub green spaces was related to the satisfaction in leisure activities and the 'quality of life' that people expect to enjoy at parks or other green areas in general. Rather than focusing on direct and visible benefits, which might come from green infrastructure's technological elements, people hoped that parks and green areas have macroscopic values. For hydrological characteristics, the 'ecologically manages stormwater' was applied the most in planning hub green spaces in cities, and it mainly took the form of technological elements or factors. Third, the planning elements pertaining to ecological characteristics were identified as a combination of strategies and technological elements that 'reintroduces native plants' and 'habitat for wildlife'. As for the plans to instill eco-friendly aspects, the study found that the research on air, climate, weather, heat reaction, soil, energy efficiency, and use and application of resources is important. However, it was difficult to measure the potential quantitative benefits of 'reusing or recycling materials', 'reducing urban heat', and 'cooling air temperature'. The result of this study is meaningful in that it can be used for the assessment of urban hub green spaces in the future.

• Resources Recycling
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• v.26 no.3
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• pp.32-38
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• 2017

For the massive recycling of mine tailings, which are an inorganic by-product of mining process, in the field of civil engineering, pretreatments to extract heavy metals are required. This study focuses on the use of pre-treated tailings as substitute fillers for controlled low-strength material (CLSM). As a comparative study, untreated tailing, microwave-treated tailing and magnetic separated with microwaved tailing were used in this study. Cement contents amounting to 10%, 20% and 30% by the weight of the tailings were designed. Both compressive strength and flowability for all types of mixture were satisfied with the requirements of the American Concrete Institute (ACI) Committee 229, i.e., 0.3-8.3 MPa of compressive strength and longer than 200 mm flowability. Furthermore, all mixtures showed settlements less than 1% by volume of the mix.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.3
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• pp.205-214
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• 2018

This paper deals with the experimental study on the hygrothermal ageing effect to the strength of Carbon Fiber Reinforced Plastics (CFRP) materials for marine leisure boat manufactured by vacuum assisted resin infusion method. The experiments performed consist of tensile, flexural and shear tests according to American Society for Testing and Materials (ASTM) and Korean Industrial Standards (KS) test methods. Test coupons are varied from uni-directional(UD, $0^{\circ}$, $90^{\circ}$), Bi-Directional (BD), and Double-Bias (DB) carbon fiber fabrics in conjunction with epoxy resin. The results of tensile test show that tensile strength reduces significantly while not the same degree of reduction is observed for elasticity modulus with respect to the existence of hygrothermal ageing effect. This implies that the tensile strain induced from external load holds steady values but ultimate strength values change widely under hygrothermal ageing effect. In case of the flexural test, $0^{\circ}$ UD shows more strength reduction than $90^{\circ}$ UD while BD has reduced values in both flexural strength and elasticity modulus under hygrothermal ageing effect. It is learned that the bending strain induced from external load and ultimate strength values are reduced with respect to hygrothermal ageing effect. Shear test performed only on DB materials, and the results show marginal reduction in ultimate strength and moderate reduction in elasticity modulus. This means that the shear strain varies more than ultimate shear strength with respect to hygrothermal ageing effect. The experiment conducted in this paper clearly demonstrates the differences in material properties of the CFRP for the consideration of hygrothermal ageing effect. Findings obtained from this experimental study can serve as a fundamental input data for the realistic structural responses of marine leisure boat built in CFRP materials.

• Journal of the Korean Institute of Landscape Architecture
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• v.22 no.4
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• pp.95-117
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• 1995

This study was carried out to investigate Korean native trees in the America landscape through arboretums, the plant inventory of America, computer files for accessions from Korea, source lists of plants and seeds, and seed and plant nursery company. The results were as follows; 1. Korean native trees introduced in America and Canada were 119 species, 116 species were being cultivated in arbrids were being sold in nurseries, new cultivars were selected from 32 species, and hybrids were bred from 5 species. 2. Abies koreana, Malus baccata, and Stewartia koreana were being cultivated in many arboretums and sold in many nurseries. Also there were new hybrids as well as new cultivars. 3. 25 species including Albizzia julibrissin were being cultivated in many arboretums and sold in many nurseries. Also there were new hybrids. 4. Ilex integra and Ilex rotunda were being cultivated in many arboretums and sold in many nurseries. There were no new cultivars, but there were new hybrids. 5. 44 species including Abies holophylla were being cultivated in many arboretums and sold in many nurseries. There were no new cultivars or hybrids. 6. Populus tremula var. davidiana was being cultivated in many arboretums. There were new cultivars of 'Erecta', 'Gigas', 'Pendula', but no new hybrids. They were not sold by any nurseries. 7. 41 species including Abies nephrolepsis were being cultivated in many arboretums. But they were not sold by any nurseries. They didn't have any new cultivars or hybrids. 8. Diospyros kaki 'Kyungsan Bansi', Elaeocarpus sylvestris var. ellipticus, and Pyrus serotina 'Dankae' were not being cultivated in arboretums in America but some nurseries were selling those species as well as new cultivars. 9. Only 3 species (Berchemia berchemiaefolia, Carpinus eximia, and Chionanthus retusus var. coreana which are native Korean plants) were not introduced in America or Canada.