| Summary: | 碩士 === 國立雲林科技大學 === 營建工程系碩士班 === 99 === Scour monitoring of bridge piers and foundations has recently attracted a considerable attention in engineering practice and academics. Nevertheless, the stability and accuracy of its related research works have not been able to reach a satisfactory level. This study chooses Kao-Ping-His Cable-stayed Bridge as the research target and is aimed to develop an efficient scour evaluation method based on the ambient vibration measurements of bridge structures. The ambient vibration measurements in different directions are first conducted on the girder, inside the girder and on the pier top to identify various modal frequencies of girder and those of the local pier. The finite element model of the cable-stayed bridge is then constructed with SAP2000 to perform the modal analysis with original design parameters. Combining the above results, this study further determines the best boundary support conditions for the finite element model to fit the identified modal frequencies of bridge girder. Based on this globally best fitted FE model, the soil stiffness and the scour depth at pier P2 are then evaluated in two sequential steps. The optimal soil stiffness is first determined by fitting the critical bridge frequencies with a known deposit height at pylon P2. After the determination of soil stiffness, the scour depth at P2 is then evaluated by fitting two sensitive frequencies of local pier modes.
|
|---|
