• Title/Summary/Keyword: Cable Force

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A Study on Dynaniic Analysis for Earthquake Design of cable-stayed Bridges (사장교의 내진설계를 위한 동적해석에 관한 연구)

  • 이진휴;이재영;이장춘
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.36 no.1
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    • pp.103-115
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    • 1994
  • The dynamic earthquake analysis of plane cable-stayed bridge structures was formulated and implemented into a computer program which analyzes plane cable-stayed bridge structu- res subjected to initial cable tensions, member dead and live loads and seismic loads. Cable-stayed bridges were modelled as multi-degrees of freedom systems with lumped- mass. Various earthquake responses such as dynamic deflection, bending moment, shear force and cable tension were investigated by the dynamic analyses in the form of the time history analysis. The time history analysis was based on the mode superposition method. The study revealed that Fan-l type cable-syayed bridges is generally superior to other types for the earthquake proof even though aspects of deflection and section force of each type presents respective advantages and disadvantages. The study provided a method to design the sections of cable-stayed bridges under seismic loads with various design parameters related to structural types. The study is expected to be useful for effective design of cable-stayed bridges with conside- ration of earthquake.

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Optimal sensor placement for cable force monitoring using spatial correlation analysis and bond energy algorithm

  • Li, Shunlong;Dong, Jialin;Lu, Wei;Li, Hui;Xu, Wencheng;Jin, Yao
    • Smart Structures and Systems
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    • v.20 no.6
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    • pp.769-780
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    • 2017
  • Cable force monitoring is an essential and critical part of the safety evaluation of cable-supported bridges. A reasonable cable force monitoring scheme, particularly, sensor placement related to accurate safety assessment and budget cost-saving becomes a major concern of bridge administrative authorities. This paper presents optimal sensor placement for cable force monitoring by selecting representative sensor positions, which consider the spatial correlativeness existing in the cable group. The limited sensors would be utilized for maximizing useful information from the monitored bridges. The maximum information coefficient (MIC), mutual information (MI) based kernel density estimation, as well as Pearson coefficients, were all employed to detect potential spatial correlation in the cable group. Compared with the Pearson coefficient and MIC, the mutual information is more suitable for identifying the association existing in cable group and thus, is selected to describe the spatial relevance in this study. Then, the bond energy algorithm, which collects clusters based on the relationship of surrounding elements, is used for the optimal placement of cable sensors. Several optimal placement strategies are discussed with different correlation thresholds for the cable group of Nanjing No.3 Yangtze River Bridge, verifying the effectiveness of the proposed method.

Finite Element Analysis on Impedance Parameters of Anchor Plate of Structural Cables Under Cable Force Changes (구조용 케이블의 장력 변화에 따른 정착부의 임피던스 특성에 대한 유한요소해석)

  • Nguyen, Khac-Duy;Park, Jae-Hyung;Hong, Dong-Soo;Lee, Ju-Won;Kim, Jeong-Tae;Na, Won-Bae
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2010.04a
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    • pp.783-786
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    • 2010
  • This paper presents a finite element analysis on impedance parameters of anchor plates of structural cables under the change in cable forces. To achieve the objective, four approaches are implemented as follows: Firstly, theoretical background of electro-mechanical impedance is described. Secondly, anchor plates of structural cables are selected to experimentally examine the relationship between impedance parameters and cable force changes. Thirdly, finite element analysis is performed to verify the experimental results. Fourthly, a comparison between the experimental and numerical analysis on impedance parameters of anchor plate of structural cables under cable force changes is carried out.

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A Study on Diagnosis of The Energized Status of 22.9kV Multigrounded Underground Power Cable (22.9kV 다중 접지 지중 전력 케이블의 가압 상태 진단에 관한 기초 연구)

  • Kim, Chang-Gyo;Hong, Jin-Su;Jeong, Yeong-Ho
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.48 no.10
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    • pp.699-703
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    • 1999
  • An experimental study to identify the energized status of the 22.9kV underground power cable by the detection of vibration has been performed. We have derived that there exists vibration at double the line frequency in live cables by electromagnetic force. The relative amplitudes of the cable vibration according to the energized status of the cable were calculated by computer simulation. The cable vibration can also be picked up by accelerometer. A prototype was tested on the underground distribution system in Chonan substation, KEPCO. Comparison between simulation results and field test results was performed. The results showed that the energized status of the calble can be identified by measuring the vibration of the cable using accelerometer.

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Effects of tensioning forces on the structural behavior of cable-stayed bridges

  • Lam, Pauline Lin Li;Kang, Thomas H.K.
    • Steel and Composite Structures
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    • v.43 no.4
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    • pp.457-464
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    • 2022
  • Optimization in distribution of stay cable forces is one of the most difficult aspects in the design of cable-stayed bridges. This article attempts to examine tension force influence on structural behavior of cable-stayed bridges. For the examination, finite element modeling using nonlinear static and nonlinear modal analyses was completed and compared to structural experimental results. Variables analyzed in this parametric study were: 1) Number of stay cables; 2) Tension of the stay cables, and 3) Stay cable pattern - harp and semi-fan patterns. Though the findings from the analysis are limited to the tested models, the study gives insight on the structural behavior of actual cable stayed bridges.

Comparison Study of An Improved Initial Force and TCUD Method for Initial Shape Analysis of Cable-Stayed Bridges (사장교의 초기형상해석을 위한 개선된 초기부재력법 및 TCUD법의 비교연구)

  • Kim, Dong-Yeong;Jo, Kyeong-Sik;Kim, Moon-Young
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.25 no.1
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    • pp.101-108
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    • 2012
  • Initial shape analysis for cable-stayed bridges should be able to find optimizated initial cable forces and unstrained length that minimize deflection and bending moments of the deck and pylon. Comparison study of an improved initial force method and TCUD method for determination of initial cable forces in cable-stayed bridges is presented in this paper. For this purpose, an elastic catenary cable element and a nonlinear frame element are firstly described. And concepts and algorithm of two analysis methods are then presented. Finally to demonstrate the validity and the accuracy of two methods, numerical examples for initial state problems of cable-stayed bridges are given and compared based on these methods.

Study on the Distribution of Electromagnetic Force for 154 kV Power Transmission Cable on Dual Underground Lines by Normal and Earth Fault Current (지중 2회선 154 kV 송전케이블의 정상 및 지락고장에 따른 전자기력 분포에 관한 연구)

  • Kim, Hui Min;Kim, So Young;Im, Sang Hyeon;Park, Gwan Soo
    • KEPCO Journal on Electric Power and Energy
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    • v.1 no.1
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    • pp.21-27
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    • 2015
  • The goal of this study is the size and distribution of the electromagnetic force generated by the current flowing through the second underground line of 154kV power transmission cables by using electromagnetic finite element analysis. So we interpret how mutually electromagnetic force has an effect on the comparable judgement of Trefoil, Duct and Flat, which shows in a numerical arrangement. 154kV OF 1200SQ Cable 1.281km not only is applicable to modeling for underground transmission cable but also examine the effect of line to line, phase to phase and size and direction of the electromagnetic force preparing for the occurrence of normal state and single-phase earth fault, which are arranged in trefoil, duct and flat formation between sections. As showing how the trajectory, and size distribution of the electromagnetic force translate as the arrangement of the cables when a steady-state current and a fault current flows on the underground cables, I hope that when Underground transmission is designed, this data will be useful information.

Determination of Member Force Ratios for Self-equilibrium State of Multi-Layered Cable Dome Type Structures (다층 케이블 돔형 구조물의 자기평형을 위한 부재력 비율 결정)

  • Kim, Jae-Yeol
    • Journal of Korean Association for Spatial Structures
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    • v.13 no.2
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    • pp.75-82
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    • 2013
  • For each cable component in a cable dome structure, pre-tension is needed for stability of whole the structure. The summation of these pre-tension at each joint should be zero to achieve the self equilibrium structure. The first step in cable dome structure analysis is to find the ratio of pre-tension in each member which can produce a stable and structure on self-equilibrium. In this paper, a new method based on the basic principle of closed force polygon for equilibrium system is proposed for the determination of self-equilibrium mode of cable dome structure. A single layer cable dome and two multi layer type domes have been analyzed. The ratios of cable members are determined by the presented method, and check the validation of the results by numerical calculation.

Evaluation of Tension Force of Stay Cables Using Vibration Method (진동법을 이용한 인장 케이블의 장력 추정에 관한 연구)

  • Kim, Nam-Sik;Jeong, Woon
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.12 no.12
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    • pp.956-963
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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 according to rapidly upgrade their related technologies. Generally stay cables as a critical member need to be rearranged for being satisfied with design tension forces. In this purpose, a vibration method has been applied to estimate the tension forces exerted on existing stay cables. In this study, cable vibration tests were tarried out to evaluate the cable tension forces comparing with theoretical and practical formulas. Using the measured frequencies obtained from free vibration and Impulsive tests, an accuracy of the estimated tension forces is confirmed according to use the first single mode only or higher multiple modes.

The Study on Countermeasures of Electromagnetic Force by Three Phase Short-Circuit Test of Underground Transmission Cable (송전케이블 삼상단락 실증시험을 통한 전자력 대책방안 연구)

  • Kang, Ji-Won;Park, Hung-Sok;Yoon, Jong-Keon;Kim, Yang-Sang;Hong, Dong-Suk;Chang, Woo-Seog
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.12
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    • pp.2342-2348
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    • 2009
  • Even though underground transmission cable is an essential transmission method to supply stable power for downtown and population center, the interaction of electromagnetic force by fault current is very large comparing to overhead transmission line due to restricted installation space such as tunnel, and close consideration is required for it. This paper presents countermeasures to reduce and release the effect of electromagnetic force with rope binding and installation of spacer and describes its efficacy through three phase short-circuit test, which will be utilized as basic materials for improvement and development of cleat, hanger, etc. to reduce and release effect of electromagnetic force in the future.