• Journal of Korean Society of Steel Construction
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• v.17 no.6 s.79
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• pp.727-736
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• 2005

This study presents a method of determining the optimum cable tension forces for the proper initial equilibrium state of a cable-stayed bridge using the least square method. The proposed method minimizes the errors, i.e., the differences, such as the deflection and the moments of the girder and the tower, between the target values from a continuous beam by considering the cable anchor point as supports of the girder and the responses obtained from the analysis of the entire cable-stayed bridge system. Especially, the proposed method can selectively control the adjustment of the tower moment, the girder moment, and the deflections by introducing the weighing matrix. Through numerical analysis and comparisons with existing studies, the usefulness and validity of the proposed method was verified.

• Journal of the Korean Society for Nondestructive Testing
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• v.27 no.4
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• pp.339-344
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• 2007

Safety of large scale cable in bridge is very important because it may cause the unwanted catastrophic failure. Although the proof load were considered at the design stage, its soundness must be monitored continuously because the cable may be broken out without warning by the variable external load. The cable tension of in-use structures has been mainly measured by the resonance method and its use has been limited because of relatively large measurement uncertainty. Recently a new magnetic method was developed and its reliability is known to be good for evaluating the cable tension. In this study a system which can deliver the calibrated load to the cable was developed and the measurement reliability of developed magnetic sensor according to the change of external load was analyzed quantitatively. The effect of magnetization frequency, bias magnetic field, and temperature on the sensor output was also evaluated.

• Journal of Industrial Technology
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• v.29 no.A
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• pp.3-8
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• 2009

Vibration characteristics of a 6kW stand alone W/T(wind turbine) system are experimentally and theoretically investigated. Vibration resonance of the tower-cable system is monitored and the data are analysed and compared with the analytical results. To predict the resonance speed of the cable supported W/T, Rayleigh-Ritz method is applied to the tower-guy cable coupled system. Parametric study on the relation of the cable tension, cable elasticity and resonance frequency is carried out. Results of the study are utilized to design the stable structure of small size wind turbines which consist of a pivoted tower and guy cables.

• 한국정보통신설비학회:학술대회논문집
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• 2005.08a
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• pp.242-247
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• 2005

통신전주는 케이블을 가공에 설치하거나 가입자 댁내로 인입시키기 위해 케이블을 지지하는 옥외 시설물로서 케이블을 쉽고 경제적으로 포설할 수 있는 장점이 있어 통신망 구축에 널리 사용되어 왔으며 특히 최근에는 FTTH(유사 FTTH 포함) 구축이 활발히 진행됨에 따라 전주에 부착물을 취부하는 경우가 많아지고 있어 통신전주의 활용도가 한층 더 높아지고 있는 상황이다. 그러나 최근 태풍 "매미" 등 극심한 기상환경 변화로 인해 통신시설물의 피해를 초래하고 있어 통신시설물의 풍하중에 대한 규정을 강화하고 있는 추세에 전주에 추가 부착물 취부에 따른 풍하중에 대한 전주의 안전 문제가 제기됨에 따라 전주의 안전성 검토가 절실히 요구되어 있는 실정이다. 따라서, 본 논문에서는 부착물이 취부되는 통신전주의 풍하중에 대한 안전성 검토 방법을 제시하고 나아가 안전한 전주가 되도록 보강할 수 있는 전주 보강기술을 소개하고자 한다.

• Journal of the Korean Society of Hazard Mitigation
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• v.3 no.4 s.11
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• pp.103-109
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• 2003

A numerical analysis of cable-stayed bridge is conducted to determine optimum longitudinal modulus of elasticity which represents the boundary condition between the tower and main girder. The effect of longitudinal modulus of elasticity is investigated for different loading condition (live load, wind load, seismic load), respectively. There are significant changes in the member forces as variations of longitudinal modulus of elasticity, such as, $k_h$=e=100tonf/m/bearing (live load), $k_h$=e=1000tonf/m/bearing (seismic load), However, the wind loads do not affect member forces. The optimum longitudinal modulus of elasticity is determined from considering minimum member forces in the numerical analysis results.

• 건축구조
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• v.12 no.4
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• pp.56-57
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• 2005

홍대앞의 지상4층, 지하3층의 전시판매시설, 도심지의 부족한 녹지공간을 해소하고자 300평의 대지에 공원을 조성하고 건물은 필로티를 두어 통행과 이동이 용이하도록 하였다. 전체건물은 트러스아치로 이루어진 주 구조체에서 기둥을 내려 각층 슬래브를 받치는 매단구조이며 2개의 도로가 교차되는 지점으로 다수의통행인에 대응하도록 전시실을 케이블로 지지된 캔틸레버로 내밀어 공간을 만들었다.

• Magazine of the Korea Institute for Structural Maintenance and Inspection
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• v.17 no.3
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• pp.31-35
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• 2013

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.2 s.54
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• pp.181-188
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• 2009

Measuring the tensile strength of steel cables used to support bridges is a critical inspection item in terms of the safety of a bridge. Today, cable tension is measured with the vibration method and loadcell. Recently, some advanced countries have conducted studies on measuring tension with magnetic method and are suggesting prospective results. Since there were no such studies ongoing in Korea, we began a study on measuring tension with magnetic method as we are undergoing researches to improve the precision of measurements. It is necessary to consider the influence for the magnetic field and the temperature of steel cables in tension measurement of magnetic method. In this paper, we tested an output characteristic of tension sensor according to temperature and deduced temperature compensation coefficient in the given magnetic field and applied the compensation coefficient to the tension measurement system in the lab. We analyzed and evaluated testing results for the output voltages of the tension sensor according to cable tensions.

• Journal of the Earthquake Engineering Society of Korea
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• v.1 no.3
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• pp.45-58
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• 1997

An analysis algorithm and a computer program have been developed to clarify the geometrically nonlinear response characteristics of a suspension bridge subject to the support excitation. The Finite Element procedures are utilized for the application to a self-anchored suspension bridge or to a mono-duo cable suspension bridge. The propagation of earthquake wave is simulated by taking a record as the input at the left anchorage of the bridge, and addign appropriate time delay to the other inputs for the purpose of considering the multi-support effects. According to the application for a mono-duo self-anchored suspension bridge, it has been found that the effects of nonlinear behavior and multi-support excitation are notable for this relatively short-spanned suspension bridge.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.5A
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• pp.255-266
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• 2012

Main cable of a suspension bridge is the important member which shows the overall structure integrity at bridge completion. Configuration of main cable is a free hanging state at cable erection completion and is different from that at bridge completion supporting the dead loads such as hanger, girder, and so on. Accordingly, the configuration control under cable erection is considerably significant because the configuration at cable erection completion has direct influence on that at bridge completion. That is performed by sag adjustments at center, side span and tension adjustments at anchor span. The former needs the sag sensitivity which represents the control quantity of strand length corresponding to that of sag. The latter requires the tension sensitivity which shows the change of strand tension according to that of strand temperature. In this study, the fundamental equations of cable were derived with the assumption of either catenary or parabola shape, the differential-related equations using chain rule on horizontal tension were drawn from those and finally the estimation methods of the sag / tension sensitivity were proposed from both those. The nonlinear numerical analysis flow charts of sag sensitivity based on the catenary equations were proposed and the sag sensitivities grounded on the differential-related equations were compared with the results using them for various parameters of sag change. Also, considering the combinations of sag change parameters, the calculation method of the final variation for the cable sag was suggested. For the real suspension bridge under construction with PPWS method, the sag/tension sensitivity were estimated considering the construction conditions like the change of PPWS length, PPWS temperature, bridge span, etc.. We hope that this study will be a systematic guideline for the configuration control under main cable erection and improved highly by field verification in the real bridge site.