• Title, Summary, Keyword: 케이블 강성

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A Study on the Bending and Torsional Behaviors of Cable-Stayed Bridges under a Concentrated Moving Load (집중 이동하중을 받는 사장교의 휨 및 비틈 거동에 관한 연구)

  • Chang, Sung Pil;Yhim, Sung Soon;Chu, Seok Beom
    • Journal of The Korean Society of Civil Engineers
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    • v.9 no.3
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    • pp.1-12
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    • 1989
  • The nonlinearity of a cable-stayed bridge results from the large displacement of main girder due to a long span, the catenary action of cables and the flexural stiffness reduced by large axial forces. The dynamic behaviour of a cable-stayed bridge plays an important role in determining its safety. Especially, when the eccentrically moving load is applied to a cable-stayed bridge, the torsional vibration and vertical vibration are coupled and moreover the variation of cable tensions shows important dynamic characteristics. This dissertation presents a theoretical study and a finite element procedure for analysis of a cable-stayed bridge under a eccentrically moving load. Attention is focused on the dynamic behaviours such as dynamic increments of cable tensions and nodal displacements, with the variety of velocities and eccentricities of moving load. It is found that a moving load with eccentricity can have significant effects upon the responses; the torsion of bridge deck and the increments of cable tensions, according to the present results in this study.

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Experimental Study for Ultimate Behavior of Steel Cable Stayed Bridge Under Construction (실험을 통한 시공 중 강사장교의 극한거동 연구)

  • Lee, Kee Sei;Kim, Seung Jun;Choi, Jun Ho;Kang, Young Jong
    • Journal of Korean Society of Steel Construction
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    • v.24 no.6
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    • pp.683-692
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    • 2012
  • The girders of cable stayed bridge are subjected to not only the bending moments but also additional compressive axial forces due to the horizontal components of cable forces. Because of these axial forces, the stiffness of girder can be decreased, and this problem should be considered especially for under-construction model rather than the full model. Korean domestic design specification suggests the linear elastic eigen value analysis for the stability problem of cable stayed bridges. However, this method cannot be applied to the under construction model because various geometric nonlinear characteristics cannot be considered. Therefore, in this study, 3 models which are assumed to be constructed by balanced cantilever will be considered experimentally and analytically to analyze the behavior of steel cable stayed bridges.

Effect of Geometric Shapes on Stability of Steel Cable-stayed Bridges (기하형상에 따른 강사장교의 안정성에 관한 연구)

  • Kim, Seung-Jun;Han, Seung-Ryong;Kim, Jong-Min;Cho, Sun-Kyu;Kang, Young-Jong
    • Journal of Korean Society of Steel Construction
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    • v.23 no.1
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    • pp.13-27
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    • 2011
  • This paper presents an investigation of the structural stability of cable-stayed bridges, using geometric nonlinear finite-element analysis and considering various geometric nonlinearities, such as the sag effect of the cables, the beam-column effect of the girder and mast, and the large displacement effect. In this analytic research, a nonlinear frame element and a nonlinear equivalent truss element were used to model the girder, mast, and cable member. The live-load cases that were considered in this research were assumed based on the traffic loads. To perform reasonable analytic research, initial shape analyses in the dead-load case were performed before live-load analysis. In this study, the geometric nonlinear responses of the cable-stayed bridges with different cable arrangement types were compared. After that, parametric studies on the characteristics of the structural stability in critical live-load cases were performed considering various geometric parameters, such as the cable arrangement type, the stiffness ratios of the girder and mast, the area of the cables, and the number of cables. Through this parametric study, the effect of geometric shapes on the structural stability of cable-stayed bridges was investigated.

Stability Analysis of Steel Cable-stayed Bridges under Construction Stage (폐합 전 강사장교의 안정성 해석)

  • Kim, Seung-Jun;Shim, Kyung-Suk;Won, Deok-Hee;Cho, Sun-Kyu;Kang, Young-Jong
    • Journal of Korean Society of Steel Construction
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    • v.23 no.1
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    • pp.99-111
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    • 2011
  • This paper presents an investigation of the structural stability of cable-stayed bridges in the construction stage, using geometric nonlinear finite-element analysis and considering various geometric nonlinearities, such as the sag effect of the cables, the P-${\Delta}$ effects of the girder and mast, and the large displacement effect. Initial shape analysis and construction-stage analysis were performed to determine the equilibrium of the structure in the construction stage. After that, geometric nonlinear analysis was performed to study structural stability. In this study, the weight of the derrick crane and the key segment were considered the main external loads, which were applied to the tip of the center span. The cable arrangement type and the stiffness ratios of the girder and mast were considered the main parameters of the analytic research. Based on the results of the analysis, the change in the buckling mode and critical load factors with respect to the cable arrangement type and the stiffness ratios of the girder and mast was investigated. The buckling modes of the steel cable-stayed bridges in the construction stage were classified, and the ranges of the stiffness ratios of the girder and mast, which show these classified buckling modes, were suggested.

Experimental and Analytical Studies on the Non-Linear behaviors of Pre-Stressed Steel H-Beams (프리스트레스트 H형강 거더의 비선형 거동에 대한 실험적 및 이론적 연구)

  • Kim, Moon-Young;Kim, Nak-Kyung;Oh, Yong-Hwan
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.32 no.6
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    • pp.359-366
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    • 2019
  • Experimental and analytical studies on the behavioral characteristics of a pre-stressed (PS) steel girder are conducted to investigate the effects of deviators on the non-linear inelastic properties of the PS system. In this regard, 4 test specimens consisting of a steel H-beam, a straight cable with eccentricity, anchorages, and deviators are built and failure tests are performed under two-point loading. In addition, in-plane elastic deformation theories for the PS system without a deviator, and with three deviators at regular intervals are analytically formulated and solved using a symbolic calculation technique. To verify the validity of the experimental and the proposed analytical theories, the results obtained using FEM models composed of beam elements, rigid beam elements, and truss cable elements, are compared to the experimental results and the analytical solutions. As a result, it is determined that externally installed un-bonded deviators inhibit flexural deformation of the deformed beam to such an extent that their elastic stiffness, and failure strength are significantly improved compared to those of the PS system without deviators.

A Study on the Performance Improvement of High-Pylon Extradosed Bridge adopting Fatigue Loading Condition (국내 설계하중의 피로특성을 적용한 고주탑 엑스트라도즈드교의 성능개선에 관한 연구)

  • Lee, Young Jin;Shin, Seung Kyo;Lim, Yun Mook
    • Journal of The Korean Society of Civil Engineers
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    • v.30 no.2A
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    • pp.137-148
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    • 2010
  • This study proposes the optimal ratio of vertical load-carrying capacity (${\beta}$) by investigating structural performances and economic efficiency in the extradosed bridges. Without design standards for the extradosed bridge, Japanese design standards have been used domestically. For the design live load, DL24 is found to be more adequate than DB24. Using the DL24 load, parameter studies are carried out. The parameters are 'main tower height', 'main girder stiffness', and 'cable arrangement'. As a result, it is found that one side cable-stayed extradosed bridges are more economical than double side cable-stayed extradosed bridges. This study also shows that when the ratio of vertical load-carrying capacity(${\beta}$) is 30~50% in the extradosed bridge with the ratio of tower height to main span length 1/6, the extradosed bridge is most economical because of the cable stress less than the allowable stress.

Dispersion Characteristics of Wave Forces on Interlocking Caisson Breakwaters by Cross Cables (크로스 케이블로 결속된 인터로킹 케이슨 방파제의 파력분산특성)

  • Seo, Ji Hye;Yi, Jin Hak;Park, Woo Sun;Won, Deck Hee
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.27 no.5
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    • pp.315-323
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    • 2015
  • Damage level of coastal structures has been scaled up according to increase of wave height and duration of the storm due to the abnormal global climate change. So, the design criteria for new breakwaters is being intensified and structural strengthening is also conducted for the existing breakwaters. Recently, interlocking concept has been much attention to enhance the structural stability of the conventional caisson structure designed individually to resist waves. The interlocking caisson breakwater may be survival even if unusual high wave occurs because the maximum wave force may be reduced by phase lags among the wave forces acting on each caisson. In this study, the dispersion characteristics of wave forces using interlocking system that connect the upper part of caisson with cable in the normal direction of breakwater was investigated. A simplified linear model was developed for computational efficiency, in which the foundation and connection cables were modelled as linear springs, and caisson structures were assumed to be rigid. From numerical experiments, it can be found that the higher wave forces are transmitted through the cable as the angle of incident wave is larger, and the larger the stiffness of the interlocking cable makes larger wave dispersion effect.

Blade Type Field Vs Probe for Evaluation of Soft Soils (연약지반 평가를 위한 블레이드 타입 현장 전단파 속도 프로브)

  • Yoon, Hyung-Koo;Lee, Chang-Ho;Eom, Yong-Hun;Lee, Jong-Sub
    • Journal of the Korean Geotechnical Society
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    • v.23 no.12
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    • pp.33-42
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    • 2007
  • The assessment of shear wave velocity($V_s$) in soft soils is extremely difficult due to the soil disturbances during sampling and field access. After a ring type field $V_s$ probe(FVP) has been developed, it has been applied at the southern coastal area of the Korean peninsular. This study presents the upgraded FVP "blade type FVP", which minimizes soil disturbance during penetration. Design concerns of the blade type FVP include the tip shape, soil disturbance, transducers, protection of the cables, and the electromagnetic coupling between transducers and cables. The cross-talking between cables is removed by grouping and extra grounding of the cables. The shear wave velocity of the FVP is simply calculated by using the travel distance and the first arrival time. The large calibration chamber tests are carried out to investigate the disturbance effect due to the penetration of FVP blade and the validity of the shear waves measured by the FVP. The blade type FVP is tested in soils up to 30m in depth. The shear wave velocity is measured every 10cm. This study suggests that the upgraded blade type FVP may be an effective device for measuring the shear wave velocity with minimized soil disturbance in the field.

Development of ultra high voltage-large capacity O.F cable (초고압 대용량 O.F 케이블의 개발)

  • Kang, S.H.;Lee, K.J.;Kim, C.S.;Choi, Y.H.
    • Proceedings of the KIEE Conference
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    • pp.265-267
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    • 1991
  • In this paper, we describe the development of 345kv OF cables to contain also the cable employing new insulation paper, PPLP (Poly propylene Laminated paper). The cables all show very excellent properties, especially PPLP cable has less the dielectric loss and better the impulse & A.C strength than the one employing the conventional paper. Therefore, according to use PPLP cable, it seems to be several advantages such as the compact of system, the increasing capacity, and the decreasing energy loss etc.

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Classification of Degradation Process with XLPE Cable Specimen (XLPE 전력용 케이블 시편의 열화에 따른 분류)

  • Park, Sung-Hee;Park, Jae-Yeol;Kang, Seong-Hwa;Lim, Kee-Joe
    • Proceedings of the KIEE Conference
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    • pp.195-197
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    • 2003
  • In this paper, Neural Networks is studied for estimation of XLPE cable specimen according to degradation. And these data making use of a computer-aided discharge analyser, a combination of statistical and discharge parameter was calculated to discrimination processing stage of degradation. NN has not bad recognition rate result of discrimination for degradation stage because discharge characteristics are very similar to between degradation stage. So, there is some improvement for applied NN.

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