| Summary: | 碩士 === 國立雲林科技大學 === 營建工程系碩士班 === 92 === The Kao Ping Hsi Bridge is the longest cable-stayed bridge in Taiwan. Although there was no damage to this bridge during the 921 earthquake, the Kao Ping Hsi Bridge is possible to be damaged in the future. In case that the damage is not found and accumulated, abrupt collapse of the bridge could happen and result in sever life and financial losses. Therefore it is necessary to carry out routine structural health monitoring of the Kao Ping Hsi Bridge. This study conducts a series of structural analyses of the Kao Ping Hsi Bridge using the SAP2000 program. First, the critical sections of the bridge when subjected to various overloading cases are found. Then the XTRACT program is used to analyze these critical sections and determine their cracking moment, yielding moment, and ultimate moment. After identifying the locations of damage for various overloading cases, the natural frequencies and mode shapes for the original and damaged structures are calculated to study whether it is possible to detect these damages from the changes in modal parameters of the Kao Ping Hsi Bridge.
The results of this study show that the prestressed concrete girder of the Kao Ping Hsi Bridge would be damaged in the overloading cases of live load and settlement. However, the modal parameters of the damaged bridge are almost unchanged, which demonstrates that it is impossible to detect this kind of damages from the changes in modal properties. Comparatively, in the cases of overloaded axial and lateral earthquake forces, the damages in the pylon result in apparent changes in vibration periods. Therefore it should be feasible to detect if the pylon of the Kao Ping Hsi Bridge is damaged due to large seismic loadings by measuring modal data of the bridge.
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