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Title |
Application of Back Analysis Technique Based on Direct Search Method to Estimate Tension of Suspension Bridge Hanger Cable
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Authors |
김진수(Jin-Soo Kim) ; 박재봉(Jae-Bong Park) ; 박광림(Kwang-Rim Park) ; 박동욱(Dong-Uk Park) ; 김성완(Sung-Wan Kim) |
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DOI |
https://doi.org/10.11112/jksmi.2023.27.5.120 |
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Keywords |
역해석 기법; 직접탐색법; 행어케이블 장력; 현수교; 진동법 Back analysis technique; Direct search method; Hanger cable tension; Suspension bridge; Vibration method |
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Abstract |
Hanger cable tension is a major response that can determine the integrity and safety of suspension bridges. In general, the vibration method is used to estimate hanger cable tension on operational suspension bridges. It measures natural frequencies from hanger cables and indirectly estimates tension using the geometry conditions of the hanger cables. This study estimated the hanger cable tension of the Palyeong Bridge using a vision-based system. The vision-based system used digital camcorders and tripods considering the convenience and economic efficiency of measurement. Measuring the natural frequencies for high-order modes required for the vibration method is difficult because the hanger cable response measured using the vision-based system is displacement-based. Therefore, this study proposed a back analysis technique for estimating tension using the natural frequencies of low-order modes. Optimization for the back analysis technique was performed by defining the difference between the natural frequencies of hanger cables measured in the field and those calculated using finite element analysis as the objective function. The direct search method that does not require the partial derivatives of the objective function was applied as the optimization method. The reliability and accuracy of the back analysis technique were verified by comparing the tension calculated using the method with that estimated using the vibration method. Tension was accurately estimated using the natural frequencies of low-order modes by applying the back analysis technique.
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