• Title, Summary, Keyword: 케이블 강성

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Active Control System for Mitigation of Cable Vibration in Cable-Stayed Bridges (사장교 케이블 진동저감을 위한 능동제어시스템)

  • Hwang, In-Ho;Jeong, Cheol-Oh;Lee, Jong-Han;Lee, Jong-Seh
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.20 no.5
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    • pp.557-563
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    • 2007
  • Rain-wind induced cable vibration can cause serious problems in cable-stayed bridge. External dampers attached to the cables have become widely accepted as an effective means for stay-cable vibration suppression. For very long stay-cables, however, such damper systems are rendered ineffective, as the dampers need be attached near the end of cables for aesthetic reasons. A recent study by the authors proposed that a movable anchorage system is replaced direct fixed support of the cable with a support through a bearing and damper. This paper extends the previous work by adding active control system to mitigate the cable vibration. The response of a cable with the proposed active control system is obtained and then compared to those of the cable with and without an external passive damper. The results show that the active control system can provide superior protection than the passive control system for a cable vibration.

The Static Unstable Characteristics of Tensegrity-Type Cable Dome according to the Structural System (구조시스템에 따른 Tensegrity형 케이블 돔의 정적 불안정 거동특성)

  • Cho, In-Ki;Kim, Hyung-Seok;Kim, Seung-Deog;Kang, Moon-Myung
    • Journal of the Korean Association for Spatial Structures
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    • v.4 no.3
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    • pp.65-75
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    • 2004
  • A shell structure, having a curvature with a curved surface, is an extremely efficient mechanical creation regard to the external load. A basic structural resistance mechanism is the structural system, which is resisted the out-of-plane direction load by in-plane forces using the structure's curvature. Therefore, it has a merit to make thin and lightweight large spacial structures using minimum materials. Among the large spare structural system, the rapid development of the membrane structures, cable structures and the hybrid structures are watched recently. But, this kind of structural system shows the unstable phenomenon by snap-through or bifurcation according to the shape of structure, and the understanding of the collapse mechanism by this phenomenon is very important to the design process. In this study, I investigated the unstable characteristics of the Geiger-type, Zetlin-type and flower-type hybrid cable dome structures, which is the lightweight hybrid structures using compression and tension elements continuously, according to the difference of structural system.

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Equivalent Suspension Bridge Model for Tower Design of Multi-span Suspension Bridges (다경간 현수교 주탑 설계를 위한 등가 현수교 모델)

  • Choi, Dong-Ho;Na, Ho-Sung;Yi, Ji-Yop;Gwon, Sun-Gil
    • Journal of Korean Society of Steel Construction
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    • v.23 no.6
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    • pp.669-677
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    • 2011
  • The multi-span suspension bridge generally has more than three towers and two main spans. To economically and effectively design a multi-span suspension bridge, the proper stiffness ratio of the center tower to the side tower must be determined. This study was conducted to propose a method of figuring out briefly the structural behavior of the towers in a multi-span suspension bridge. In the equivalent suspension bridge model, the main cable of the multi-span suspension bridge is idealized as an equivalent cable spring, and the external loads of horizontal and vertical forces that were calculated using the tensile forces of the main cable were applied on top of the towers. The equilibrium equations of the equivalent multi-span suspension bridge model were derived and the equations were solved via nonlinear analysis. To verify the proposed method, a sample four-span suspension bridge with a main span length of 3,000 m was analyzed using thefinite element method. The displacements and moment reactions of each tower in the proposed method were compared with the FEM analysis results. Consequently, the results of the analysis of the equivalent suspension bridge model tended to be consistent with the results of the FEM analysis.

Estimation for Equivalent Flexural Stiffness of Innovative Prestressed Support(IPS) Wale (혁신적 프리스트레스트 가시설(IPS)의 띠장에 대한 등가 휨강성의 산정)

  • Kim, Sung Bo;Kim, Hun Kyom;Heo, In Sung
    • Journal of Korean Society of Steel Construction
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    • v.21 no.4
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    • pp.393-401
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    • 2009
  • The flexural-stiffness formula of the wale for the innovative prestressed support (IPS) system was precisely derived, and the equivalent beam stiffness was introduced for application in the actual design of the IPS wale. The cable tension forces of the IPS wale were calculated in both cases, and the axial-deformation effects were included and ignored, respectively. The central displacements of the 1-post, 2-post, 3-post, and 4-post IPS wales were calculated based on the principle of virtual work. The effects of the IPS wale length and cable inclination angle were also investigated using the derived central displacements. The simplified equivalent flexural stiffness of the IPS wale is presented herein for design purposes, and the validity of the proposed design formula was verified through its comparison with the FE and analysis solutions.

A Technical Report on the Design and Construction of Hybrid Tension Roof Structure of Incheon Munhak Stadium (인천문학경기장 지붕구조의 설계와 시공)

  • Seok Hwangbo
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • pp.194-201
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    • 2003
  • 대공간 구조시스템은 일반적으로 자중을 최소화하고 부재내력의 효과적인 사용이 매우중요하다. 따라서 준공후의 외력에 대한 구조적 거동에 대한 파악도 중요하지만 시공중의 거동에 대한 파악도 매우 중요하다. 특히 케이블 막구조의 경우 시각초기에 구조물이 불안정하지만 케이블에 장력이 도입되면서 점차적으로 구조물의 강성이 높아져 구조물이 안정화를 이루게 피므로 시공과정 해석 즉 안정화 이행과정해석이 시공계획을 설정하는 부분에서 매우 중요한 요소가 된다. 본고에서는 케이블 막구조의 실례로써 최근 완공된 인천문학 경기장 지붕구조를 대상으로 시공과정과 안정화 이행과정해석에 대한 소개를 한다. 인천문학경기장 지붕구조는 케이블에 장력을 도입하는 과정에서 발생되는 변형과 내력을 흡수하고 하부구조에 대한 영향을 최소화하기 위하여 마스크 지점의 회전과 이동이 가능한 특수공법을 채택하였으며 시공과정해석(안정화이행과정해석)을 통하여 제시된 단계별 목표장력 및 변위에 따라 시공과정이 계획되고 제어되었다. 특히 외국의 기술로 설계된 자료를 근거로 일방적으로 공사를 수행한 다른 구조물과는 다르게 국내의 기술력에 바탕한 구조 해석 등을 통하여 검증하여 최종 시공방법을 결정하였고 이러한 과정을 통하여 대공간 구조에 대한 기술력을 확보하고 확인할 수 있었으며, 그 결과 향후에는 국내의 기술력으로 이와 같은 대규모의 케이블 막구조의 설계와 시공이 가능할 것이라고 판단된다.

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A Study on Numerical Simulation for Dynamic Analysis of Towed Low-Tension Cable with Nonuniform Characteristics (불균일 단면을 갖는 저장력 예인케이블의 동적해석을 위한 수치해석적 연구)

  • 정동호
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.16 no.1
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    • pp.69-76
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    • 2003
  • Low-tension cables have been increasingly used in recent years due to deep-sea developments and the advent of synthetic cables. In the case of low-tension cables, large displacements may happen due to relatively small restoring forces of tension and thus the effects of fluid and geometric non-linearities and bending stiffness. A Fortran program is developed by employing a finite difference method. In the algorithm, an implicit time integration and Newton-Raphson iteration are adopted. For the calculation of huge size of matrices, block tri-diagonal matrix method is applied, which is much faster than the well-known Gauss-Jordan method in two point boundary value problems. Some case studies are carried out and the results of numerical simulations are compared with a in-house program of WHOI Cable with good agreements.

Estimation of Tension Forces of Stay Cables (인장 케이블의 장력 추정기법에 관한 연구)

  • Kim, Nam-Sik;Jeong, Woon;Seo, Ju-Won
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.121-126
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    • 2002
  • In a recent construction industry, cable supported structures such as a cable-stayed bridge or space stadium have been increasingly constructed. Generally the stay cables as a critical member should be adjusted to be satisfied with the design tension forces. In this purpose, a vibration method has been applied to estimate the tension forces exerted to the existing stay cables. In this study, cable vibration tests were carried out to estimate the cable tension forces comparing with theoretical and practical formulas. From the measured frequencies obtained from free vibration and impulsive tests, the accuracy of 1he estimated tension forces is confirmed according to use only the first single mode or higher multiple modes.

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막과 케이블 구조물의 형상탐색해석

  • 서삼열;권택진
    • Computational Structural Engineering
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    • v.5 no.3
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    • pp.19-28
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    • 1992
  • 이 글에서는 막 구조물의 설계에서 자주 제기되는 형상결정 문제에 대한 접근방법을 제시하고자 하였다. 형상결정 문제는 막 구조물이 휨 강성이 전혀 없거나, 빈약한 재료를 사용하는데 기인하여 제기되고, 막 구조물의 설계에서 불안정영역의 발생을 피하기 위해서는 형상의 기준면에서 곡률과 비틀림의 변화를 최소화해야 하며 이러한 변화를 최소화하기 위해서는 형상이 적용하중의 막력에 의한 평형면에 근접하는 것이 바람직하다. 또한, 초기에 막 구조물에 도입된 초기장력에 오차가 발새하면 막면은 스스로 등장력의 형태로 이동하게 되므로, 초기에 막장력의 분포가 등장력의 상태가 되도록 그 형상을 결정하는 것이 바람직하다. 따라서, 이러한 조건을 만족하는 형상탐색문제는 이러한 종류의 구조물의 설계에서는 매우 중요한 문제가 된다. 그러나 국내에서는 막과 케이블 구조물의 형상해석과 응력-변형해석에 범용적으로 사용될 수 있는 프로그램의 개발이 미약하고 이러한 구조방식에 대한 국내의 인식에 크게 부족한 실정이다. 따라서 이 글이 막과 케이블 구조물의 설계에서 형상탐색해석이 반드시 필요한 이 구조물의 구조적 특성을 이해하는데 조금이라도 도움이 될 수 있기를 기대한다.

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Erection Sequence Analysis of Suspension Bridge Considering to Sliding of Main Cable (주케이블의 슬라이딩을 고려한 현수교의 시공단계 해석)

  • Yhim, Sung-Soon;Kong, Min-Sik;Kim, Byeong-Cheol
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.13 no.3
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    • pp.164-172
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    • 2009
  • Anchors and saddles are used to have sufficient geometrical rigidity and make target configuration of main cable of suspension bridge. Neglecting the sliding effect at saddles, points at them have been idealized as fixed nodes in lots of former studies. In general, sliding effects are reported to show significant structural behaviors of main cable and cause to the different responses of bridges. During early erection steps of the suspension bridge, especially, the sliding effect occurs easily because there is large difference of cable tension between main and side span in removing set-back ropes or not applying set-back. This study presents the finite element analysis considering to cable sliding effect and shows the comparison of differences between sliding and non-sliding at election sequence. The analysis of sliding between main cables and saddles needs to obtain more realistic responses because the analysis result can represent unfavorably different responses of bridges. Moreover, the sliding analysis method and results in this study can be used to basic criteria in engineering design and construction steps.