• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.104-408
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• 2003

케이블 장대 교량의 해석에 있어서 기하적인 비선형만을 고려한 해석이 보편적이었다. 하지만 이 연구에서는 내진 해석시 케이블지지 교량이 비탄성적으로 거동 할 수 있기 때문에, 기하적인 비선형 이외에 재료적인 비선형을 고려할 필요가 있음을 보이고자 한다. 극한 하중 상태를 모사하기 위하여 사하중에 하중계수를 곱하여 하중을 증가시켜 중력방향으로 하중을 가하였고, 지진에 대한 하중 상태를 모사하기 위하여 교축방향의 지진 하중에 대한 등가의 등분포 하중과 이의 0.3배에 해당하는 수직 방향 하중을 동시에 가하였다. 이러한 해석을 통하여 자중의 2배 이상의 하중이 가해지면 거더가 비탄성적으로 거동 할 수 있고, 또한 교축 방향과 수직 방향의 설계지진하중을 고려할 경우 수평방향의 구속이 모두 풀리면 주탑이 비탄성적으로 거동 할 수 있음을 알 수 있다. 따라서 케이블지지 교량의 지진 해석시 특정한 경우에 있어서는 비탄성 거동을 고려해야 할 필요가 있을 것으로 보인다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.295-311
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• 2021

In this study, an experiment was carried out on the field applicability of tension measuring devices of the cables in cable-stayed bridges. The vibration method was used to estimate the tension of cables of cable-stayed bridge, and the mode characteristics of the cable were analyzed using a cable tension measuring device. GTDL360, NI Module, and 9 Axes Motion Sensorwere applied to estimate the cable tension of five target bridges. Numerical analysis of the five target bridges was conducted to analyze the natural frequency of the cable and cable tension. The estimated tension of the cable based on field measurements and estimated tension of cable by numerical analysis were compared with the estimated tension of the cable based on field measurements. The analysis showed that the measured tension of the cable based on field measurements was within the margin of error. Therefore, it is safe to apply these measuring devices to the site. As a result of comparing and analyzing the values of the acceleration-based cable estimation tension and numerical analysis of the field demonstration bridge, the acceleration-based cable estimation of tension is deemed appropriate within the allowable range. On-site applicability analysis revealed limitations of the measuring devices, such as the installation location of sensors and weather conditions, so continuous follow-up research on smart cable tension measuring systems is expected.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.136-142
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• 2008

Recently, cabled-suspension bridges and suspension bridge have been increasingly built in korea. But such structures were often damaged by fire due to car collison. In this study, the cabled-suspension bridges constructed under the kind of the project of national road aggrandizement are modeled using Solid Works 2007. The COSMOS FloWorks 2007 software are used for Heat Transfer Analysis and Thermal Stress Analysis. The safety of wire, HDPE pipe and stainless steel pipe are investigated. The major variables for the analysis are the temperature of the heat source, the distance between the fire-proof bulk head and the heat source, wind velocity, and the height of the end of Stainless steel pipe.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.3
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• pp.129-138
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• 2005

This paper presents a methodology for the determination of optimal managing criteria for cable tension force in cable-stayed bridges using acceleration data acquired by monitoring system. There are many long span bridges installed with monitoring system in Korea. The monitoring systems are installed to diagnose abnormal behavior or damages in bridges and to warn these to bridge management agency. In cable-stayed bridges, the cable tension force could be an important indicator of abnormal behavior because of the geometric configuration of the cable-stayed bridge. If the management value of cable tension force is set too high or too low, then the monitoring system could not warn properly for the abnormal behavior of a bridge. Generally, the management value is set by empirical or engineering judgment, but in this paper, a new methodology for the determination of managing criteria for cable tension force is proposed based on the probability distribution model for tension force and reliability analysis. The proposed methodology is applied to a real concrete cable-stayed bridge in order to investigate its applicability.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.218-221
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• 2011

본 연구에서는 추계학적 해석을 통하여 구한 교량의 동적 변위와 동일한 변위를 발생시키는 등가 정적 버페팅 하중을 구하는 방법을 제시하고, 단순 양단 캔틸레버에 적용하여 타당성을 검증하였다. 모드 형상이 복잡한 사장교의 경우에 2개 이상의 모드를 포함해야 정확도를 높일 수 있는 것으로 나타났다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.4
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• pp.37-44
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• 2019

The purpose of this study is to rationally determine the priority of seismic reinforcement of main(key) members of bridges. Cable Supported bridge was selected as the evaluation target and the reliability based on the probability distribution was used to evaluate the seismic fragility of the key members as a quantitative indicator. The safety factor, which is a random variable, is considered an artificial (fixed load and live load) load and a natural (earthquake, wind, temperature, etc.) load. The seismic load is applied as a possible earthquake during the lifetime of the bridge. From analyzing the fragility of each key member based on the seismic reliability, it can be concluded that the shoe (23.8%) was the most fragile, where the other members are ranked as place concrete (20.5%), pier (18.9%), foundation (17.3%) and cable (5.0%) respectively.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.4
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• pp.121-125
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• 2018

This paper presents the assessment of 7-wire strand monitoring using acoustic emission technique for bridges. 7-wire strand is widely used construction materials to provide additional tensile force to bridges. PSC (PreStressed Concrete) bridge and cable-stayed bridge are representatives for such cases. However, as the bridge aging progresses recently, corrosion problems of strand are emerging. For this reason, various NDT (Non-Destructive Test) methods for cable inspection are being studied and applied to the field. One of the NDT methods, acoustic emission technique, is known as an effective technique to detect cable damage and breakage. In this study, to evaluate the applicability of acoustic emission technique to bridges, acoustic emission signals according to damage of the strand were acquired and analyzed by tensile test. Moreover, The optimal AE sensor type was selected for field application. As a result, it is considered that the acoustic emission technique will be able to detect corrosion breakage and signs of rupture.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.2
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• pp.27-33
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• 2004

Dynamic response analysis is conducted for a floating bridge subjected to multiple support earthquake excitation. The floating bridge used in this study is supported by discrete floating pontoons and horizontal pretension cables supported at both ends of the bridge. The bridge is modeled with finite elements and the hydrodynamic added mass and added damping due to the surrounding fluid around pontoons are obtained using boundary elements. During the analysis the concept of retardation function is utilized to consider the frequency dependency of the hydrodynamic coefficients. Multiple support excitation is introduced at both ends of the bridge and the time history response is compared to that of a simultaneous excitation. The results show that the multiple support excitation yields larger values in some responses. for example in cable tensions. than the sumultaneous excitation.

• Computational Structural Engineering
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• v.20 no.1 s.75
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• pp.65-70
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• 2007

• 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.