• Title/Summary/Keyword: 구조 연결부

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Crack Width Control on Concrete Slab using Half-Depth Precast Panels with Loop Joints (루프이음 반두께 프리캐스트 바닥판을 갖는 콘크리트 바닥판의 균열폭 제어)

  • Kim, Dong Wook;Shim, Chang Su
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.35 no.1
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    • pp.19-29
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    • 2015
  • As the half-depth precast concrete decks are increasingly applied to the construction sites, researches on connection details have been increased. For design of concrete bridge deck with half-depth precast panels, it is required to provide appropriate details of transverse loop joints between panels. In this paper, the structural performance of precast decks was evaluated to investigate continuity of the proposed loop joint details. From the results, the validity of the joints for the continuity of deck was observed in the aspect of flexural strength and crack control. The ultimate strength increased 1.52 times as the reinforcement spacing in the joint was reduced. In terms of crack control, direct crack width calculation for the loop joint showed appropriate results comparing with measured crack width.

Resistance Increasing Factor of Connected-pile Foundation for Transmission Tower in Clay (점토지반에 근입된 송전철탑 연결형 말뚝기초의 저항력증가계수)

  • Kyung, Doo-Hyun;Lee, Jun-Hwan;Paik, Kyu-Ho;Kim, Dae-Hong
    • Journal of the Korean Geotechnical Society
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    • v.28 no.8
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    • pp.31-41
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    • 2012
  • Pile foundation for transmission tower constructed in weak ground can cause the damage of the tower due to the different settlement between the foundations. In Japan and USA, connected-pile foundations whose 4 foundations are connected each other by beams were used for transmission tower (TEPCO 1988, IEEE 2001). Resistance increasing factors for connected-pile foundation signify increasing amount of resistance due to the effect of connected-pile material. In this study, we performed model lateral load tests of connected-pile foundations for transmission tower and found the resistance increasing factors for connected-pile foundation. The tests were performed in silty clay, and the resistance increasing factors were founded in various conditions that lateral load directions and height, the stiffness of beams in the connected-pile foundations were changed. The resistance increasing factors from our research were presented as a function of normal lateral loading height and normal stiffness of the connected-pile material. The resistances which were estimated from the resistance increasing factors were similar to measured values.

Strength Analysis of Joint Between Steel Plate and CFRP Laminated Splice Plates Patched by Adhesive (접착제를 사용한 CFRP와 강재 이음부의 강도 해석)

  • Park, Dae-Yong;Lee, Sang-Youl;Chang, Suk-Yoon
    • Journal of the Korean Society for Advanced Composite Structures
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    • v.2 no.2
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    • pp.13-19
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    • 2011
  • This paper presents the stress distribution of the damaged butt joint of steel plate using CFRP laminates when the flange in tension zone of steel box girder is welded by butt welding. When CFRP sheets are patched on tension flange of steel-box girder, the stress distribution of a vertical and normal direction on damaged welding part is shown as parameters such as a variation of the thickness of adhesive, the overlap length with steel, and the modulus of elasticity of CFRP sheets. For the study, we wrote the computer program using the EAS(Enhanced assumed strain) finite element method for plane strain that has a very fast convergency and exact stress for distorted shape.

Wing-Fuselage Joint Design Improvement Using Nonlinear Analysis Considering Contact (접촉을 갖는 날개-동체 조인트의 비선형 해석을 통한 설계 개선)

  • Kim, Gwang-Su;Yun, Se-Hyeon;Sim, Jae-Yeol;Lee, Yeong-Mu
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.30 no.2
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    • pp.108-114
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    • 2002
  • In this paper, nonlinear finite element analysis is performed to ensure structural safety and to suggest the design improvement of wing-to-fuselage joint of the KSR-III rocket. In the joint, wings are attached to fuselage by fitting wing attachment part into the groove on the fuselage frame, and load transfer between wing and fuselage frame is accomplished mainly throug the contact of two members as well as fastening bolts. The careful finite element modeling has been proposed for the purpose of analyzing problems with relatively complicated load path. The detailed bolt modeling is conducted and GAP elemets are used to simulate contact problem between joined members and bolts. The suggested design improvement is verified by structural testing and the analysis results are compared with test results.

Evaluation of Steel Tube Connection in Precast Concrete Double Wall System (프리캐스트 콘크리트 더블월 시스템의 각형 강관 연결부 성능평가 )

  • Yujae Seo;Hyunjin Ju
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.27 no.2
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    • pp.25-32
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    • 2023
  • In this study, a double wall system is introduced, which was invented to simplify the complicated manufacturing process of the existing precast concrete (PC) double wall systems and to remove defects such as laitance that may occur during the production of concrete panels. An experimental study was conducted to investigate the tensile resisting capacity of the steel tube which is embedded in the precast concrete panel to keep the spacing between PC panels and to prevent damage of the PC panels during transportation and casting concrete onsite. The experiment was planned to determine the detail of effective steel tube connection considering the steel plate treatment method according to the formation of the opening, the presence of embedded concrete, and the reinforcement welding for additional dowel action as key variables. As a result, the ultimate tensile strength increased by 20-30% compared to the control specimen (ST) except for the steel tube specimen (ST_CP) which has steel plates bent inward at the end part of the steel tube. Since the specimen (ST_CON) filled with concrete inside the control specimen has no additional process and cost for the steel tube connections compared to the control specimen during the production of the developed double wall system, it is determined to be the appropriate detail of steel tube connection.

Optimal Design of Linear Viscous Damping System for Vibration Control of Adjacent Building Structures (인접구조물의 진동제어를 위한 선형감쇠시스템의 최적설계)

  • Park, Kwan-Soon;Ok, Seung-Yong;Koh, Hyun-Moo
    • Journal of the Earthquake Engineering Society of Korea
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    • v.10 no.3 s.49
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    • pp.85-100
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    • 2006
  • This paper proposes an optimal design method of linear viscous dampers for the seismic performance of two adjacent structures with different heights. Accordingly, connection method using diagonal bracing between two floors and connection method between two structures are considered, and the effectiveness of the latter method is confirmed through the comparison of the frequency response functions with respect to damping capacity. Moreover, optimal damping to minimize the response of the adjacent structures in the frequency domain is found. The sensitivity of natural frequency and modal damping according to the damper capacity at each floor is obtained for the optimally designed system. From the sensitivity analysis, the modal damping is evaluated to be very sensitive to the damper installed at higher floor. Therefore, sensitivity-based damping distribution method is proposed. Diagonal bracing connection method, uniform distribution method and sensitivity-based distribution method are compared to each other in terms of seismic performance. The comparative results demonstrate that the proposed method is an effective seismic design method for the adjacent structures.

DC Voltage Balancing Control Scheme for a Cascade Multilevel Inverter (직렬 연결형 다중 레벨 컨버터를 위한 DC전압 평형화 기법)

  • Song O.S.;Lim J.S.;Nam K.H.
    • Proceedings of the KIPE Conference
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    • 2003.07a
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    • pp.341-344
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    • 2003
  • 직렬연결형 다중레벨 컨버터(cascade multilevel converter)는 각기 절연된 DC전압원과 H-bridge 인버터가 한 단위를 이루고, 각 단위 인버터의 출력을 직렬 연결한 구조로서, 부하(전동기)에 정현파에 가까운 전압을 인가할 수 있는 시스템이다 각 H-bridge인버터의 DC전압원으로는 배터리 또는 커패시터등이 사용되는데, 일반적인 경우 각 H-bridge 컨버터의 입출력 파워가 틀려지게 되며, 따라서 DC전압간 불균형이 발생하게 된다. DC전압간 불균형이 발생하면 원하는 전압벡터를 정확하게 발생시킬 수 없게 되고, 고조파 하모닉이 만들어질뿐 아니라, 경우에 따라서는 DC전압원측에과 전압 또는 저전압 폴트가 발생할 수 있다. 본 논문은 N개의 H-bridge 인버터의 DC전압을 측정하지 않고, 전체 상출력 전압만을 측정하여 각 DC전압을 추정하고, 스위칭 패턴을 변경하여 DC전압을 평형화하는 방법을 제안한다. 모의실험을 통해서 알고리즘의 동작여부를 검증하였다.

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Pushover Analysis of a Five-Story Steel Framed Structure Considering Beam-to-Column Connection (보-기둥 접합부를 고려한 5층 철골골조구조물의 비탄성 정적해석)

  • Kang, Suk-Bong;Lee, Jae-Hwan
    • Journal of Korean Society of Steel Construction
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    • v.22 no.2
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    • pp.129-137
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    • 2010
  • In this study, a five-story steel frame was designed in accordance with KBC2005 to evaluate the effect of the beam-column connection on the structural behavior. The connections were designed as a fully rigid connection and as a semirigid connection. A fiber model was utilized to describe the moment-curvature relationship of the steel beam and column, and a three-parameter power model was adopted for the moment-rotation angle of the semirigid connection. To evaluate the effects of higher modes on structural behavior, the structure was subjected to a KBC2005-equivalent lateral load and lateral loads considering higher modes. The structure was idealized as a separate 2D frame and as a connected 2D frame. The pushover analysis of 2D frames for the lateral load yielded the top displacement-base shear force, design coefficients such as overstrength factor, ductility ratio, and response modification coefficient, demanded ductility ratio for the semirigid connection,and distribution of plastic hinges. The sample structure showed a greater response modification coefficient than KBC2005, the higher modes were found to have few effects on the coefficient, and the lateral load of KBC2005 was found to be conservative. The TSD connection was estimated to secure economy and safety in the sample structure.

Graph abstraction for Genome scale graph layout of metabolic pathways (유전체 수준 대사 경로 그래프 레이아웃을 위한 슈퍼노드화 방안에 관한 연구)

  • Song Eun-Ha;Kim Min-Kyung;Lee Sang-Ho
    • Proceedings of the Korean Information Science Society Conference
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    • 2006.06a
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    • pp.58-60
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    • 2006
  • 대사 경로를 자동으로 레이아웃 해주는 시스템에 있어 노드 수가 일정수 이상으로 증가할수록 에지 크로싱이 기하급수적으로 증가하는 문제가 있다. 따라서 유전체 수준에서 대사 경로간의 관계(Cross-talk) 등을 살펴보기 위해서는 레이아웃 상에 나타나는 에지 크로싱을 줄이고 이를 압축하여 표시할 필요가 있다. 이는 개개의 대사경로에 대한 레이아웃 분만 아니라 대사 경로간의 관계 등 다양한 단계와 방식의 레이아웃이 가능한 시스템이 필요하기 때문이다. 본 논문에서는 레이아웃 상에 나타나는 에지 크로싱에 의한 가독성 저해를 피하기 위하여 대상 경로 상에 존재하는 연결성 높은 부그래프를 찾는 모듈을 개발하였다. 또한 각각의 부그래프를 슈퍼노드로 치환하는 방식을 적용함으로써 대사 경로를 이해하기 쉽도록 하였다. 또한 이러한 과정은 반복적, 혹은 역방향으로 실행할 수 있도록 하였다. 실험결과, 대사 경로 상에 존재하는 연결성 높은 부그래프들은 그래프밀도값 Q가 0.8로 나타나, 단백질 상호작용 네트워크에 비하여 희소한(sparse) 네트워크 구조를 보임을 알 수 있었다.

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Development of a Health Monitoring System for Critical Parts of Wind Turbine Towers and Foundation Structures (풍력발전기 타워 및 기초 취약부 건전성 모니터링 시스템 개발)

  • Jaehun Jeong;Moonok Kim;Jongho Park;Seok-Young Jeong
    • Journal of Wind Energy
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    • v.15 no.2
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    • pp.23-36
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    • 2024
  • In this study, a health monitoring system was developed for the two most vulnerable parts of a wind tower support structure: the connection between steel towers (L-Flange) and the concrete foundation-steel tower connection. To select assessment parameters for health monitoring, detailed FEM analysis was conducted using the ABAQUS program. Additionally, a testbed was established near the Jeju Woljeongri wind turbine farm to evaluate the applicability of measurement data by installing sensors. Through computational analysis and relevant criteria review, we defined limits for measurement parameters by vulnerable section. We categorized the structural safety evaluation into four stages: normal, caution, warning, and danger, and selected management criteria for each stage. From this, an algorithm to evaluate safety was developed, and a visualized monitoring platform based on the established critical parts monitoring system was developed.