• Title/Summary/Keyword: building direction

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Effect of Anisotropy on the Wear Behavior of Age-Treated Maraging Steel Manufactured by LPBF (시효 열처리를 적용한 LPBF 제조된 마레이징 강의 마모 거동에 대한 이방성의 영향)

  • Seung On Lim;Se-Eun Shin
    • Journal of Powder Materials
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    • v.31 no.4
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    • pp.308-317
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    • 2024
  • Maraging steel has excellent mechanical properties resulting from the formation of precipitates within the matrix through aging treatment. Maraging steel fabricated by the laser powder bed fusion (LPBF) process is suitable for applications including precise components and optimized design. The anisotropic characteristic, which depends on the stacking direction, affects the mechanical properties. This study aimed to analyze the influence of anisotropy on the wear behavior of maraging steel after aging treatment. The features of additive manufacturing tended to disappear after heat treatment. However, some residual cellular and dendrite structures were observed. In the wear tests, a high wear rate was observed on the building direction plane for all counter materials. This is believed to be because the oxides formed on the wear track positively affected the wear characteristics; meanwhile, the bead shape in the stacking direction surface was vulnerable to wear, leading to significant wear.

Comparative Evaluation of Condensation by Type and Layer Around Built-in Furniture of Apartment Buildings (WUFI를 이용한 공동주택 붙박이가구의 층별·형태별 결로 생성 비교 평가)

  • Yoo, Jiwon;Chang, Seong Jin;Lee, Jongki;Wi, Seunghwan;Kim, Sumin
    • Journal of the Korea Furniture Society
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    • v.29 no.1
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    • pp.31-39
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    • 2018
  • Recently, as the continuously increasing of the one-person households, builders were focusing on a built-in furniture development for efficiency. Through the dead space of the space can be reduced. Also, Condensation that occurs in a built-in furnitures installation space may result in different results depending on the room's direction, floor, finish, adjacent room effect, occupant's lifestyle. In this background, it can be considered in terms of functional aspect and morphological aspect by using WUFI2D simulation system. As a result, the tendency of occurrence of condensation was examined by comparing the water content and the growth potential of fungus graph which came from WUFI2D. Results of this study are as followings: Built-in furniture, both top & bottom open, is more stable to condensation than the built-in furniture with the top or bottom open. Also, Among from the top floor built-in furniture to the bottom of it, the bottom one is more stable to condensation.

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Improvement Directions for the G-SEED System from the Resident's Perspective - Focused on Certification Assessment Criteria for Apartment Buildings -

  • Choi, Yeo Jin;Lhee, Sang Choon
    • KIEAE Journal
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    • v.14 no.4
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    • pp.19-26
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    • 2014
  • The building section is providing immediate causes for global climate change problems since it takes about 50% of carbon emission, 20~50% of waste discharge, 33% of energy consumption, 40% of resource use, and 17% of water consumption. So, many countries over the world have developed and implemented green building certification systems to assess sustainable performances of buildings since the early 1990s. In korea, the green building certification system to induce the diffusion of sustainable buildings was first introduced in 2002 and developed as an improved version of the G-SEED(Green Standard for Energy and Environmental Design) system in 2013 after major revisions of related legislations. This research conducts a survey targeting residents on an apartment building that was certified as green building and examines the importance of assessment criteria on apartment buildings to certify green buildings using the Analytic Hierarchy Process(AHP) method. And it proposes a new direction on certification assessment standards from the resident's prospective. As a result, assessment criteria such as indoor environment, ecological environment, energy & environment pollution, and maintenance management among 7 main ones turned out important on assessing the G-SEED system for apartment buildings, while criteria such as material & resource, water circulation management, and land use & transportation did relatively unimportant.

Development of Large Tuned Mass Damper with Stroke Control System for Seismic Upgrading of Existing High-Rise Building

  • Hori, Yusuke;Kurino, Haruhiko;Kurokawa, Yasushi
    • International Journal of High-Rise Buildings
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    • v.5 no.3
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    • pp.167-176
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    • 2016
  • This paper describes a large tuned mass damper (TMD) developed as an effective seismic control device for an existing highrise building. To realize this system, two challenges needed to be overcome. One was how to support a huge mass that has to move in any direction, and the second was how to control mass displacement that reaches up to two meters. A simple pendulum mechanism with strong wires was adopted to solve the first problem. As a solution to the important latter problem, we developed a high-function oil damper with a unique hydraulic circuit. When the mass velocity reaches a certain value, which was predetermined by considering the permissible displacement, the damper automatically and drastically increases its damping coefficient and limits the mass velocity. This velocity limit function can effectively and stably control the mass displacement without any external power. This paper first examines the requirements of the TMD using a simple model and clarifies the constitution of the actual TMD system. Then the seismic upgrading project of an existing high-rise building is outlined, and the developed TMD system and the results of performance tests are described. Finally, control effects for design earthquakes are demonstrated through response analyses and construction progress is introduced.

Governing Design Factors of GFRP-Reinforced Concrete Bridge Deck (GFRP 근 보강 콘크리트 교량 바닥판의 설계지배인자)

  • Cho, Jeong-Rae;Park, Young Hwan;Park, Sung Yong;Cho, Kunhee;Kim, Sung Tae
    • Journal of the Korean Society of Safety
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    • v.30 no.6
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    • pp.70-77
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    • 2015
  • In this study, the governing design factors of GFRP-reinforced concrete bridge deck are analyzed for typical bridges in Korea. The adopted bridge deck is a cast-in-situ concrete bridge deck for the prestressed concrete girder bridge with dimensions of 240 mm thickness and 2.75 m span length from center-to-center of supporting girders. The selected design variables are the diameters of GFRP rebar, spacings of GFRP rebars and concrete cover thicknesses, Considering the absence of the specification relating GFRP rebar in Korea, AASHTO specification is used to design the GFRP-reinforced concrete bridge deck. The GFRP-reinforced concrete bridge deck is proved to be governed by the criteria about serviceability, especially maximum crack width, while steel reinforced concrete bridge deck is governed by the criteria on ultimate limit state. In addition, GFRP rebars with diameter of 16 mm ~ 19 mm should be used for the main transverse direction of decks to assure appropriate rebar spacings.

Present State of Membrane Structures in Japan

  • Oda, Kenshi
    • Journal of Korean Association for Spatial Structures
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    • v.2 no.2 s.4
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    • pp.11-15
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    • 2002
  • Formerly, it was called a tent and now, it is called membrane structure. If saying a tent, it imagines the tent of Bedouin, Mongolia and North American Indian. It became clear from the excavated wall painting that have been covered with the retractable roof of the canvas on the auditorium at the amphitheater in Pompeii and became a topic. These tents were made of the animal skins or fabric woven with the flax plants, and these tents are still used. However, if saying membrane material at present, it says the one to have applied a coating resin to the textile. Because the base fabric of membrane material is a woven fabric, the relation between the stress and the strain is different to the direction of the weaving thread. Moreover, the tensile force must always occur in the membrane surface. From these reasons, because the membrane structure corresponds to the particular building material and the construction method about the Building Standard Law, it must be examined specially that the membrane structural building have the same or any more safety as the provisions which was set to the Building Standard Law. Therefore, the technical standards about the membrane structural building became indispensable. In the paper, the kinds of the membrane materials, which are used for the membrane structural buildings, and technical standards process of the creating for the membrane structure buildings are introduced. Lastly, some of the soccer stadiums for 2002 FIFA World Cup KOREA/JAPAN which be covered with the roof of the membrane structures are presented.

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A Study about Indoor Environmental Improvement of Green Building Certification System through, POE (거주 후 평가를 통한 친환경 인증제도의 실내환경 개선 방향에 대한 연구)

  • Lee, Myung-Joon;Lee, Jong-Chan;Kim, Kwoang-Ho;Kim, Byung-Sean
    • Proceedings of the SAREK Conference
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    • 2006.06a
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    • pp.1055-1060
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    • 2006
  • The Korean Green Building Certification System was activated from 2005. The purpose of it is to improve the quality of residential unit. Recently, people stay inside of building more than for 90% of a day Accordingly, it is really important for them to make the quality of Indoor Environmental better, in brief, to develop the indoor environmental factor in KGBC is important. One of the best way to develop the system is to do research based on POE because the area of problem can be realized. Accordingly, we get the information about POE from another research for the part of the indoor environment for residential unit to have the critical mind about the KGBC, and tried to compare the factors to another which is from foreign Green Building Certification System such as LEED, BREEAM, GBTool, After they have been analyzed, we could find that some of factor need to be revised and added. Also, there was one problem that many part of factor was created without any consideration of direction of each space in residential unit.

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Seismic Response Characterization of Shear Wall in Auxiliary Building of Nuclear Power Plant (지진에 의한 원전 보조건물 전단벽의동적 응답 특성 추정)

  • Rahman, Md Motiur;Nahar, Tahmina Tasnim;Baek, Geonhwi;Kim, Dookie
    • Journal of the Earthquake Engineering Society of Korea
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    • v.25 no.3
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    • pp.93-102
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    • 2021
  • The dynamic characterization of a three-story auxiliary building in a nuclear power plant (NPP) constructed with a monolithic reinforced concrete shear wall is investigated in this study. The shear wall is subjected to a joint-research, round-robin analysis organized by the Korea Atomic Energy Research Institute, South Korea, to predict seismic responses of that auxiliary building in NPP through a shake table test. Five different intensity measures of the base excitation are applied to the shaking table test to get the acceleration responses from the different building locations for one horizontal direction (front-back). Simultaneously to understand the global damage scenario of the structure, a frequency search test is conducted after each excitation. The primary motivation of this study is to develop a nonlinear numerical model considering the multi-layered shell element and compare it with the test result to validate through the modal parameter identification and floor responses. In addition, the acceleration amplification factor is evaluated to judge the dynamic behavior of the shear wall with the existing standard, thus providing theoretical support for engineering practice.

REQUIREMENTS FOR AUTOMATED CODE CHECKING FOR FIRE RESISTANCE AND EGRESS RULE USING BIM

  • Jiyong Jeong;Ghang Lee
    • International conference on construction engineering and project management
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    • 2009.05a
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    • pp.316-322
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    • 2009
  • The more repetitive, complex and objective the work, the more effective automation is. Code checking is an example of this. Checking building codes through a thick set of drawings is error-prone and time-consuming. In order to overcome this problem, several organizations have initiated efforts to automate building-code checking. Initiated study mainly focused on checking codes for invalidation, required size and crash, and then area of checkable codes have been expanding. But, it has not been considered for codes regarding anti-disaster/egress, which is also issued these days. This study is about how to automatically check codes for anti-disaster and egress based on Korea building codes. The codes can be categorized as five sections: egress way, material/capability, principals of evacuation, evacuation stairway and fire protection partition. To check automatically, there are problems, such as expression of codes for egress and limitation of extractable information from the BIM model. This paper shows what problems exist and assignments to be resolved. Also, current developing processes are presented, and suggestions are made about the direction for the work that remains.

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A Numerical Study of Building Orientation Effects on Evacuation Standard in Case of Toxic Gas Leakage (독성 가스 누출 시 건물 방향이 대피 기준에 미치는 영향에 관한 수치 해석 연구)

  • Seungbum Jo
    • Journal of the Korean Institute of Gas
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    • v.27 no.4
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    • pp.12-18
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    • 2023
  • The effective evacuation strategy according to the accident scenario is crucial to minimize human casualties in the event of toxic gas leak accidents. In this study, the effect of the direction of a building and the location of an industrial complex on the increase in indoor concentration and outdoor diffusion was examined under the same leakage conditions, and effective evacuation criteria were established. In addition, the guidelines for building directions were suggested when constructing buildings that would mitigate human damage caused by chemical accidents. Three scenarios where buildings faced the front, side, and rear of the leakage direction were investigated through CFD simulations. The results revealed that when the building faced the industrial complex, both indoor and outdoor average gas concentrations increased significantly, reaching up to 120 times higher than the other two orientations. Moreover, the indoor space was filled with toxic gas substances more than twice in the same time due to the rapid increase of indoor concentration rate. In cases where the building's windows were positioned at the front, toxic gas stagnation occurred around the building due to pressure differences and reduced flow velocities. Based on our findings, the implementation of these guidelines will contribute to safeguarding residents by minimizing exposure to toxic gas during chemical accidents.