• Structural Engineering and Mechanics
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• v.71 no.3
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• pp.271-282
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• 2019

The span record of cable-stayed bridges has exceeded 1,000 m, which makes research on the maximum possible span length of cable-stayed bridges an important topic in the engineering community. In this paper, span limit is discussed from two perspectives: the theoretical span limit determined by the strength-to-density ratio of the cable and girder, and the engineering span limit, which depends not only on the strength-to-density ratio of materials but also on the actual loading conditions. Closed form equations of both theoretical and engineering span limits of cable-stayed bridges determined by the cable and girder are derived and a detailed parametric analysis is conducted to assess the engineering span limit under current technical conditions. The results show that the engineering span limit of cable-stayed bridges is about 2,200 m based on materials used available today. The girder is the critical member restricting further increase in the span length; its compressive stress is the limiting factor. Approaches to increasing the engineering span limit are also presented based on the analysis results.

• Structural Engineering and Mechanics
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• v.34 no.5
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• pp.611-623
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• 2010

Excessive stay cable vibrations can cause severe problems for cable-stayed bridges. In this paper a semiactive Magnetorheological (MR) damper is investigated to reduce cable vibrations. The control-oriented cable-damper model is first established; a computer simulation for the cable-damper system is carried out; and finally a MR damper is experimentally used to reduce the cable vibration in a laboratory environment using a semiactive control algorithm. Both the simulation and experimental results show that the semiactive MR damper achieves better control results than the corresponding passive damper.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.364-366
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• 2003

345kV XLPE Cable system was constructed between Yeongseo-Yeongdeunpo at first in Korea. XLPE cable have the advantage of OF cable. it is to raise the power transmission capacity and reduce the power loss and expenses. We also applied many new technology in this project at first. One is pre-fabricated joint which can be easily assembled in the field without any hand-skill, another is PD(Partial Discharge) test for after laying test. Especially, PD measurement for after-laying test was performed to evaluate the quality of the cable joint and termination. Through the good experience of this project, we have gotten the international competitiveness of power business.

• Smart Structures and Systems
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• v.19 no.2
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• pp.137-149
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• 2017

Under the interference of the temperature effect, the alternation of cable force due to damages of a cable-stayed bridge could be difficult to distinguish. Considering the convenience and applicability in engineering practice, simple air or cable temperature measurements are adopted in the current study for the exclusion of temperature effect from the variation of cable force. Using the data collected from Ai-Lan Bridge located in central Taiwan, this work applies the ensemble empirical mode decomposition to process the time histories of cable force, air temperature, and cable temperature. It is evidently observed that the cable force and both types of temperature can all be categorized as the daily variation, long-term variation, and high-frequency noise in the order of decreasing weight. Moreover, the correlation analysis conducted for the decomposed variations of all these three quantities undoubtedly indicates that the daily and long-term variations with different time shifts have to be distinguished for accurately evaluating the temperature effect on the variation of cable force. Finally, consistent results in reducing the range of cable force variation after the elimination of temperature effect confirm the validity and stability of the developed method.

• Journal of the Korea Society of Computer and Information
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• v.23 no.7
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• pp.1-10
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• 2018

In this paper, we propose the principles and design details of Automatic cable assembly test system and show its utility. Testing the cable assembly is required periodically or non-periodically in the system that the cable assembly performance is quite important like military equipment. There are several weaknesses when humans test the cable assembly manually. It not only takes much time but also could happen human error. To improve these disadvantages, I developed Automatic cable assembly test system. The system can be implemented by building switching control system that connect and disconnect the cable assembly and measuring devices. Through the result of the cable assembly test with this test system, we show this system makes test time short and improves of test reliability as compared with manual test.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1688-1690
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• 2001

The mechanical characteristics of XLPE cable is basic to the installation design. Especially, snake and offset design require accurate coefficient of linear expansion($\alpha$), Young's modulus(E) and bending stiffness(El) of the cable. In this paper, $\alpha$, E and El of 345kV XLPE cable was measured by experimental setup, and verified by measuring axial tension and lateral displacement in snake installation.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2007.04a
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• pp.457-462
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• 2007

The high tensile strength of steel cable enabled the development of long span cable bridges which that a better tensile element can break the limitation of current bridge design. A carbon fiber has at least strength as steel cable and is very light material relatively. Due to its characteristics. commercial carbon fiber cables are already used in place of steel prestress tendons. This study proposes a parallel carbon fiber(CF) cable for cable based on NPWS and CFCC cables. Static and nonlinear analyses reveal that the CF cable develops much less stress than the NPWS cable cyclic loads.

• Proceedings of the KIEE Conference
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• summer
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• pp.424-426
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• 2004

As power demand increases gradually, the call for underground transmission system increases. But it is very difficult and high in cost to construct new ducts and/or tunnels for power cables in metropolitan areas. HTS (High Temperature Superconducting) cable has the several useful characteristics such as increased power density, stronger fields and/or reduced losses. Therefore HTS cable can allow more power to be moved in existing ducts, which means very large economical and environmental benefits. In these days, companies world-wide have conducted researches on HTS cable. A development project for a 22.9kV class HTS cable is proceeding at a research center and university in Korea. In this paper, we investigate the expected price of HTS cable to have a merit in viewpoint of economic aspect. First, life-cycle cost of conventional cable is calculated and based on this, the expected price of HTS cable is evaluated, which HTS cable is competitive against conventional cable.

• Journal of Electrical Engineering and Technology
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• v.1 no.3
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• pp.308-312
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• 2006

The inductance difference between conducting layers of high-Tc superconducting (HTSC) power transmission cable causes the current sharing of each conducting layer to be unequal, which decreases the current transmission capacity of HTSC power cable. Therefore, the design for even current sharing in HTSC power transmission cable is required. In this paper, we investigated the current distribution of HTSC power cable with a shield layer dependent on the pitch length and the winding direction of each layer. To analyze the effect of the shield layer on the current sharing of the conducting layers of HTSC power cable, the current distribution of HTSC power cable without a shield layer was compared with the case of HTSC power cable with a shield layer. It could be found through the analysis from the computer simulations that the shield layer of HTSC power cable could be contributed to the improvement of current distribution of conducting layers at the specific pitch length and the winding direction of conducting layer. The result and discussion for the current distribution calculated for HTSC power transmission cable with a shield layer were presented and compared with the cable without a shield layer.

• Journal of Ocean Engineering and Technology
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• v.19 no.5 s.66
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• pp.34-42
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• 2005

The cable connection zone of the cable-stayed bridge transfers deal-load, live-load, and second-load to the cables on the structural joint zone of the cables and the main girders are the most critical parts in which big cable tensile forces are generated by those loads. Therefore, it is necessary to thoroughly check the main girder, structurally to secure the required stability. Because of the heavy tensile force of cables linked in the connection zone of the cable-stayed bridge, locally concentrated stress, as well as the dispersion of stress, occurs in the structurally contacted point of cable and main girder thus, we need to make a thorough investigation through a detailed structural analysis. Directly delivering the tensile force to the connection zone of the cable, the consequently big effect in the tensile force fluctuation caused by the live-load will make it necessary to review the fatigue strength. As the connection zone of the cable is designed to resist the tensile force of the cable, which is applied to a connecting section as a concentrated force, thick plates are used. These plates are frequently made of welded structure, thus, the investigation of the welding workability is inevitable.