• Journal of the Korea Concrete Institute
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• v.26 no.6
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• pp.715-722
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• 2014

In this paper, internal blast effect of reinforced concrete core structure were investigated using Ansys Autodyn, which is a specialized hydrocode for the analysis of explosion and impact. It is expected that internal blast case can give additional damage to the structure because it causes rebound of blast loads. Therefore, in this paper, the hazard of internal blast effect is demonstrated using UFC 3-340-02 criteria. In addition, analysis result of Autodyn, experimental result regarding rebound of blast load, and example of UFC 340-02 are compared to verify that Autodyn can analyze internal blast effect properly. Furthermore, progressive collapse mechanism of core structure which is one of the most important parts in high rise buildings is also analyzed using Autodyn. When internal blasts are loaded to core structure, the core structure is mostly damaged on its corner and front part of core wall from explosives. Therefore, if the damaged parts of core wall are demolished, progressive collapse of the core structure can be initiated.

• Journal of the Korean Institute of Landscape Architecture International Edition
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• no.1
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• pp.176-182
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• 2001

The case for study in this paper is the Main Plan and Management for the Fukutoshin; the restructure of Nishi Shinjuku, This plan was first outlines in 1960, and includes a vast area of 96 ha for redevelopment. It aims to create a totally new center in the city. This was the first case in Japan, and in the world of a plan of these magnitudes. involving urban landscape restructuring from three points: Landscape (open spaces for public use: the Shinjuku Central Park and the surrounding area of the buildings), transport and commercial building developments. The Landscape plan for the green areas was decided in a way to compensate the population of the area and the visitors. As a rule, high-rise building constructions are placed each one in single lots and are surrounded by open spaces and greenery. Pedestrain areas are widened and also connected by bridges in a way to allow free circulation, and interconnection between the constructions and the green areas. Another important factor is the role that Private Corporation, and public interest plays. Joining these two forces has allowed the concretization of this project. This interpolation between public and private roles was an innovation in Japan, and it also the key for the concretion of the project. The historical review of the process and management of this project help us to put into perspective the introduction of new concepts and ideas, which were not related at that time to traditional Japanese Landscaping. Furthermore we are better able to understand the substantial increase in the percentage of land dedicated to green areas in contrast to the typical standards of Japanese cities.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.2
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• pp.970-978
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• 2011

The high-rise buildings have been indiscriminately located in the good natural landscape in Busan. They destroy the mountain skyline that is the key role of urban landscape and lower the index of greenness. Busan need the efficient management methods of the mountain skyline to improve the quality of urban life, the amenity of urban landscape, and the index of greenness. This study is to propose the method of building height restriction both through the GIS bases multiple sight surface analysis and through the analysis of the floor area ratio to make up for the weakness of single sight surface analysis has been used as a means of building height restriction. It studies the residential district with Hwangreung Mountain in the background at Deeyeon-don, Nam-gu, Busan. It achieves both objectivity and time efficiency by multiple sight surface analysis. Reflecting the result of this simulation at strategic viewpoints, it enables landscape planning to be comprehensive. Lastly it suggests building height regulation for protecting the mountain skyline which responds to the local conditions.

• Journal of the Korea Institute of Building Construction
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• v.9 no.4
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• pp.85-92
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• 2009

Urban regeneration projects have been actively proceeding all over Korea. Urban regeneration has become a critical issue in the domestic construction industry, with environmental-friendly construction and high-rise buildings being emphasized. Because these projectstend to become complex, urban regeneration projects require interest and approach on a level of program management that includes traditional project management. This paper develops aprototype for a new program management information system of a supports the promotion of urban regeneration projects through the deduction of the requirements about system. The prototype of the program management information system includes functions that supply diverse information, support the process and legislation of an urban regeneration project, manage stakeholders, support decision-making, estimate and manage program risks, and manage the program level.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.2
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• pp.137-148
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• 2014

A multi-rotor is an autonomous flying robot with multiple rotors. Depending on the number of the rotors, multi-rotors are categorized as tri-, quad-, hexa-, and octo-rotor. Given their rapid maneuverability and vertical take-off and landing capabilities, multi-rotors can be used in various applications such as surveillance and reconnaissance in hostile urban areas surrounded by high-rise buildings. In this paper, the unified dynamic model of each tri-, quad-, hexa-, and octo-rotor are presented. Then, based on derived mathematical equations, the operation and control techniques of each multi-rotor are derived and analyzed. For verifying and validating the proposed models, operation and control technique simulations are carried out.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.11
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• pp.4614-4622
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• 2010

Urban Skyline is strongly influenced by high-rise buildings. It is changed and becoming over time and is formed by the human choice. This study does an analysis of the foreign urban skyline managements in three aspects: criteria and control, operation and deliberation, and citizen participation and inducement. It draws common characteristics of foreign cases; preparing rational and premeditated building height control in the aspect of district, transformation from height restrictions of individual building to height standards in the aspect of urban landscape, devising efficient design review and citizen participation methods, and administrative processing for an integrated building height management. It also suggests policy implications for preparing both comprehensive and systematic building height standards in the aspect of district to create a desirable city image and urban skyline.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.743-750
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• 2016

In this research, the effects of the strength and stiffness of shear walls on the design strength of coupling beams are studied in the shear wall-coupling beam structural system widely used as the lateral-drift resistant system of high-rise buildings. The results show that the design strength of the coupling beams decreases with decreasing concrete strength and core wall thickness, but the shape remains unchanged. In all six models, the design strength of the coupling beams has the largest value at the 10~15th floors in a 40-story building. In other words, the design strength of the coupling beams has the largest value at 0.25H~0.375H where the inflection point exists. The thicker the walls, the smaller the change in the member forces. The thickness of the coupled shear walls has more influence on the design strength of the coupling beams than the concrete strength.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.26 no.3
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• pp.24-30
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• 2003

As domestic buildings have been large-scaled, diversified and high-rise, there have been a consistent demand for design, development of construction technology and accident prevention activity as well as quality enhancement. In spite of governmental and related institutions' efforts for reducing national losses which come from numerous accidents, there have been endless small and large accidents on the construction site and thus, it is urgent to conduct empirical researches in this area. Currently safety supervision system in construction industry has enforced harm and danger prevention planning system, however it merely stick to other existing materials. In addition, it is difficult to put it into practice in that it requires bearing too much burden to draw out the planning itself in a case of large construction work. Consequently in this paper we select evaluation criteria by construction progress, classify into several categories, and regard potential danger which often occurs, as a evaluation criterion. Further step is to allow workers or collaborated companies to express their expert opinions or experiences and to encourage quality and process control and autonomous safety control by applying PSM(Process Safety Management) method using AHP(Analytic Hierarchy Process) and to development of PSM evaluation method in the construction. The reason why PSM method should be quantitative and substantial progress is because it contributes Korean constructing companies to enhancing their safety control ability and to taking an equal stance just like developed countries, thereby strengthening their competitive edges. Boost of safety control system by PSM method could make an enormous contribution to preventing construction accidents on the site by establishing and securing an autonomous safety control system.

• International Journal of High-Rise Buildings
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• v.10 no.4
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• pp.323-334
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• 2021

Concrete structures may rarely collapse in fire incidents but fire induced damage to structural members is inevitable as a result of material degradation and thermal expansion. This requires certain repairing measures to be applied to restore the performance of post-fire members. A brief review on investigation of post-fire damage of concrete material and concrete structural members is presented in this paper, followed by a review of post-fire repair research regarding various types of repairing techniques (FRP, steel plate, and concrete section enlargement) and different type of structural members including columns, beams, and slabs. Particularly, the fire scenarios adopted in these studies leading to damage are categorized as three levels according to the duration of gas-phase temperature above 600℃ (t₆₀₀). The repair effectiveness in terms of recovered performance of concrete structural members compared to the initial undamaged performance has been summarized and compared regarding the repairing techniques and fire intensity levels. The complied results have shown that recovering the ultimate strength is achievable but the stiffness recovery is difficult. Moreover, the current fire loading scenarios adopted in the post-fire repair research are mostly idealized as constant heating rates or standard fire curves, which may have produced unrealistic fire damage patterns and the associated repairing techniques may be not practical. For future studies, the realistic fire impact and the system-level structural damage investigation are necessary.

• Smart Structures and Systems
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• v.22 no.6
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• pp.727-741
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• 2018

To mitigate vibrations, tuned mass dampers(TMD) are widely used for long span bridges or high-rise buildings. Due to some durability concerns, such as fluid degradation, oil leakage, etc., the alternative solutions, such as the non-contacted eddy current damping (ECD), are proposed for mechanical devices in small scales. In the present study, a new eddy current damping TMD (ECD-TMD) is proposed and developed for large scale civil infrastructure applications. Starting from parametric study on finite element analysis of the ECD-TMD, the new design is enhanced via using the permanent magnets to eliminate the power need and a combination of a copper plate and a steel plate to improve the energy dissipation efficiency. Additional special design includes installation of two permanent magnets at the same side above the copper plate to easily adjust the gap as well as the damping. In a case study, the proposed ECD-TMD is demonstrated in the application of a steel arch bridge to mitigate the wind-induced vibrations of the flexible hangers. After a brief introduction of the configuration and the installation process for the damper, the mitigation effects are measured for the ambient vibration and forced vibration scenarios. The results show that the damping ratios increase to 3% for the weak axis after the installation of the ECD-TMDs and the maximum vibration amplitudes can be reduced by 60%.