• Steel and Composite Structures
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• v.21 no.5
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• pp.1031-1043
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• 2016

Optimization of the construction scheme of the cable-strut tensile structure based on error sensitivity analysis is studied in this paper. First, the element length was extracted as a fundamental variable, and the relationship between element length change and element internal force was established. By setting all pre-stresses in active cables to zero, the equation between the pre-stress deviation in the passive cables and the element length error was obtained to analyze and evaluate the error effects under different construction schemes. Afterwards, based on the probability statistics theory, the mathematical model of element length error is set up. The statistical features of the pre-stress deviation were achieved. Finally, a cable-strut tensile structure model with a diameter of 5.0 m was fabricated. The element length errors are simulated by adjusting the element length, and each member in one symmetrical unit was elongated by 3 mm to explore the error sensitivity of each type of element. The numerical analysis of error sensitivity was also carried out by the FEA model in ANSYS software, where the element length change was simulated by implementing appropriate temperature changes. The theoretical analysis and experimental results both indicated that different elements had different error sensitivities. Likewise, different construction schemes had different construction precisions, and the optimal construction scheme should be chosen for the real construction projects to achieve lower error effects, lower cost and greater convenience.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.4
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• pp.413-420
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• 2013

This paper includes the results of the electromagnetic finite element analysis with regard to overheating problem of the power cable tray due to asymmetric magnetic flux density. This phenomenon was experienced in the utility power plant, Korea. The influences of the power cable arrangements and material of the tray were analyzed to find the best solutions using the eddy current-thermal coupled analysis.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.5
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• pp.338-343
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• 2004

In general, the insulation and protective sheaths on electrical conductors are made of combustible substances like PVC, natural or synthetic rubbers, and other organic or synthetic materials. When an electrical fire starts due to overheating of conductors/joints or sparking/arcing, the first thing to ignite is usually the insulation on the cables. When the insulation bums, the produced fumes are very toxic. To solve the problem, we have surely need the fire resistance cable that doesn't bum in a high temperature and emit toxic fume for operating a disaster prevention installation. In this paper, we have simulated the thermal analysis for the fire resistance cable according to the values of current in a overload and a short, and the values of outside flame with the fire resistance cable of the L's company product(600 V, FR-8 : Four Core) using the finite element method(Flux2D).

• Steel and Composite Structures
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• v.12 no.5
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• pp.413-426
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• 2012

In this paper, nonlinear static analysis of three-dimensional cable stayed bridges is performed for the time dependent materials properties such as creep, shrinkage and aging of concrete and relaxation of cable. Manavgat Cable-Stayed Bridge is selected as an application. The bridge located in Antalya, Turkey, was constructed with balanced cantilever construction method. Total length of the bridge is 202 m. The bridge consists of one $\ddot{e}$ shape steel tower. The tower is at the middle of the bridge span. The construction stages and 3D finite element model of bridge are modeled with SAP2000. Large displacement occurs in these types of bridges so geometric nonlinearity is taken into consideration in the analysis by using P-Delta plus large displacement criterion. The time dependent material strength and geometric variations are included in the analysis. Two different finite element analyses carried out which are evaluated with and without construction stages and results are compared with each other. As a result of these analyses, variation of internal forces such as bending moment, axial forces and shear forces for bridge tower and displacement and bending moment for bridge deck are given with detailed. It is seen that construction stage analysis has a remarkable effect on the structural behavior of the bridge.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.2A
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• pp.85-95
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• 2012

This paper presents an investigation on the ultimate behavior of steel cable-stayed bridges using nonlinear finite element analysis method. Cable-stayed bridges exhibit various geometric nonlinearities as well as material nonlinearities, so rational nonlinear finite element analysis should be performed for investigation of the ultimate behavior. In this study, ultimate behavior of steel cable-stayed bridges was studied using rational ultimate analysis method. Nonlinear equivalent truss element and nonlinear frame element were used for modeling the cable, girder and mast. Moreover, refined plastic hinge method was adopted for considering the material nonlinearity of steel members. In this study, the 2-step analysis method was used. Before live load analysis, initial shape analysis was performed in order to consider the dead load condition. For investigation of the ultimate behavior of steel cable-stayed bridges, analysis models which span length is 920.0 m were used. Radiating type and fan type were considered as the cable-arrangement types. With various quantitative evidences such as load-displacement curves, deformed shapes, locations of the yield point or region, bending moment distribution and so on, the ultimate behavior of steel cable-stayed bridges was investigated and described in this paper.

• Structural Engineering and Mechanics
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• v.50 no.1
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• pp.37-52
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• 2014

The accurate determination of cable tension is important to the monitoring of the condition of a cable-stayed bridge. When applying a vibration-based formula to identify the tension of a real cable under sag, stiffness and boundary conditions, the resulting error must not be overlooked. In this work, by resolving the implicit frequency function of a real cable under the above conditions numerically, indirect methods of determining the cable force and a method to calculate the corresponding cable mode frequency are investigated. The error in the tension is studied by numerical simulation, and an empirical error correction formula is presented by fitting the relationship between the cable force error and cable parameters ${\lambda}^2$ and ${\xi}$. A case study on two real cables of the Shanghai Changjiang Bridge shows that employing the method proposed in this paper can increase the accuracy of the determined cable force and reduce the computing time relative to the time required for the finite element model.

• Structural Engineering and Mechanics
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• v.53 no.3
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• pp.443-453
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• 2015

Cable-beam structures characterized by variable stiffness nonlinearities are widely found in various structural engineering applications, for example in space deployable structures. Space deployable structures in orbit experience both high temperature caused by sun's radiation and low temperature by Earth's umbral shadow. The space temperature difference is above 300K at the moment of exiting or entering Earth's umbral shadow, which results in structural thermally induced vibration. To understand the thermally induced oscillations, the analytical expression of Boley parameter of cable-beam structures is firstly deduced. Then, the thermally induced vibration of cable-beam structures is analyzed using finite element method to verify the effectiveness of Boley parameter. Finally, by analyzing the obtained numerical results and the corresponding Boley parameters, it can be concluded that the derived expression of Boley parameter is valid to evaluate the occurrence conditions of thermally induced vibration of cable-beam structures and the key parameters influencing structural thermal flutter are the cable stiffness and thickness of beams.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.26 no.2
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• pp.147-155
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• 2013

In this paper structural analysis of underground electrical power cable structures which is excavated below the surface of the earth in the downtown area is carried out considering the effect of construction sequence. There are many various life-line facilities below the surface of the earth in the downtown area. MPDAP was used for finite element analysis of underground electrical power cable structures. Three typical sections are simulated by finite element models. Unbalanced equilibrium problems may be occurred when conventional finite element procedures were used for simulation of tunnel excavation. Therefore equilibrium perturbation concept was applied to solve these problems. The effects of time-dependent deformations in advancing tunnel excavation are considered in the stages of construction sequences as using the load distribution factor. It is shown that values of maximum displacement of both soil and rock surrounding underground electrical power cable structures obtained by our numerical studies are less than allowable values.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.21-33
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• 2006

The reliability analysis can be conducted more effectively by formulating the stochastic finite element method suitable for the reliability theory about the cable stayed bridge. After conducting the initial equilibrium analysis of the cable stayed bridge, the program which can conduct the linear and nonlinear stochastic finite element analysis using the perturbation method and the reliability analysis considered to the correlation of the random variable is developed. Using the results of this program about the cable stayed bridge, the characteristic of the node displacement, element force and cable tension according to the correlation of the random variable is investigated quantitatively. Also the reliability index and the failure probability are examined by the compounding the correlation of the random variable.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1994.04a
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• pp.209-216
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• 1994

Recently, cable-supported long-span bridge are widely constructed due to improved quality of cable and development of design and construction techniques. In this study, an existing cable-stayed bridge, Dolsan Bridge, has been evaluated based on the cable forces measured using vibration method. And the finite element model using in this study for the dynamic analysis has been found to be quite comparable with dynamic mode shapes and natural frequencies estimated from experimental data induced by ambient traffic excitations.