Summary: | 碩士 === 國立高雄大學 === 土木與環境工程學系碩士班 === 101 === Field vibration test is the most reliable means for determining the dynamic characteristics of an existing bridge. The results obtained in a field test can be adopted to improve the finite element model used, to evaluate the rationality of the original design, or to assess the damage occurring on a bridge after a major wind or earthquake event. The ambient vibration test is easy, practical, and economic. It is the most popular way to perform vibration tests because it utilizes common loadings such as wind, normal traffic and environmental noise as the input. To determine its actual dynamic responses under the normal loads, modal identification from the field tests was carried out for the Kao Ping Hsi cable-stayed bridge in southern Taiwan. The dynamic characteristics of the bridge identified by a time series method are compared with those obtained by the finite element analysis. The finite element model was then modified and refined based on the field test results. The results obtained from the updated finite element model were shown to agree well with the field identified results for the first few modes in the three main directions. This has the indication that a rational finite element model has been established for the bridge. The finite element model obtained herein was used as the damage index for monitoring the long-term safety of the Kao Ping Hsi cable-stayed bridge under environmental loads in the future.
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