Investigation And Analysis Of Urban Concrete Curved Beam Bridges Seismic Vulnerability

In recent years, with the frequent occurrence of the earthquake, the safety of the lifeline engineering has attracted more and more people’s attention, and bridge construction as the core of the lifeline engineering has been the first research subjects by the experts and scholars. These studies characterize the vulnerability of the bridge structure with the seismic fragility curves and describe the relationship between damage probability of bridge and ground motion parameters. Based on summarizing the results and methods on the existing research, combined with the survey of Fuzhou city concrete curve beam bridge, the typical benchmark bridge is selected and the seismic vulnerability of members which are most likely to be damaged is analyzed, then the system fragility curves are obtained. Overall, this thesis focuses on the following work and obtains the corresponding results.1、With the browse and collection of related literature home and abroad, the seismic damage of beam bridges is introduced briefly, then the method of vulnerability analysis and damage criteria and index of the members are systematically reviewed and summarized, to provide theoretical basis for the identification of damage index and the establishion of fragility curves.2、By using the finite element software SAP2000, combined with the survey of Fuzhou city of curved beam bridges and literature arrangement, the typical benchmark bridge is selected and 3-D finite element analysis model is established.3、With the incremental dynamic analysis method (IDA), nonlinear time history analysis of the curve beam bridge are conducted respectively, the seismic response of structure under different ground motion is obtained. Through statistical regression, the fragility curves of each independent component are acquired by Origin mapping software to determine the most easily damaged components and their position.4、By parameter analysis, the change trend of the seismic responses of curved beam bridge with the change of the main structure parameters is researched, influence of the curvature radius, height of pier and support layout on the structural vulnerability is analyzed and certain rules providing a theoretical basis for future design and maintenance of the bridge are accessed.Finally, the problems existing in the research are described and discussed briefly so as to offer the conclusions and recommendations for further work direction.