The Researches On Design Earthquake Action And Seismic Performance Index Of Three-span Continuous Girder Bridge On High Speed Rail

In the last decade, Chinese high speed rail has made a great achievement. Based on the corresponding documents, at the end of2014, the total operation mileage was already above16,000kilometer, which is the longest one in the world. In the railway, a very large proportion of all the structures is bridge. For example, in the railway between Beijing and Shanghai, the proportion is80.5%. In consideration of the large number of bridges on the railway, it is widely concerned that how to evaluate the seismic ability of the bridges conveniently and exactly.Currently, the main criterion that guide the seismic design of the bridges on high speed rail is Code for seismic design of railway engineering(2009), which was revised in2009. The design seismic action is the basis of the seismic performance analysis, so that it is specified in detail in all the main criteria in the world. However, there are differences between different criteria on the spefication of the design earthquake action. Thus, the main seismic criteria of the world have been compared first, and the design seismic action of Code for seismic design of railway engineering(2009) is assessed.The accuracy of the finite element model will have a large influence on the calculation result. Before calculation and analysis, the differences of the first10modes on vibration between the models using six-springs constraint and using complete constraint are compared. After that, according to the requirements of GB50111-2006(2009), the spectrum analysis is used to analyze the seismic capabilities of the bridges.According to the damage indicators proposed by Hwang, the Pushover analysis is used to roundly assess the anti-seismic abilities of original bridge models on both longitude direction and transverse direction. Besides, the plastic yielding mechanism of the two bridges are analyzed. After that, a series of whole bridge models and single pier models which are different in the height of the piers are built. Globally, the vulnerability under seismic force and the plastic yielding mechanism are analyzed.Finally, based on two different aspects:whole bridge aspect and single pier aspect. The displacement ductility factors of the two bridge types are discussed by analyzing, concluding and summarizing the results.