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The bridge is an important part in highway system. In Taiwan, bridges are frequently suffered from the foundation exposure due to the severe riverbed scour caused by flood. In order to repair the damaged foundation, this study investigated one of the substructure reconstruction method. The method use temporary supporting frame to support superstructure and replaced the substructure of the bridge. More specifically, the weight of the superstructure is transferred through the hydraulic jack to a temporary supporting frame and this process is called lifting method. During the lifting process, the displacement between the upper and lower portions of the pot bearing and the force of hydraulic jack is recorded during the lifting method. When the upper and lower portions of the pot bearing is fully detached, indicating the weight of the superstructure is fully transferred to the temporary supporting frame, the process of removing the existing foundation can started. In this thesis, a specific case history of the superstructure lifting process of the National Highway 4 Shengang Viaduct is studied. The numerical model of the highway viaduct is constructed in structural analysis software Midas and SAP2000. The load displacement relation of the pot bearing is assumed and imported to the model to simulate the lifing process. The results of the simulation is compared with the data recorded during the lifting process. The influences of various factors, including the superstructure weight, magnitude of additional dead load and live load and vertival load-displacement relation of the pot bearing, are also discussed. In addition, we also create the same model in SAP 2000, in order to verify the authenticity of the simulation from Midas. Some suggestions are also made in the end of the thesis for future application.
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