Research On The Aseismic Performance Of High-Pier Long-Span Continuous Rigid Frame Bridge In Mountainous Areas

Our country is so vast, the natural characteristic across the country is different and complex, especially in western areas where is filled of high mountains and deep valleys, the construction of railways in the region will inevitably cross the deep valleys, so that a lot of long-span high-pier Bridges emerge.In this paper, the seismic performance of a high-pier long-span rigid frame bridge in the western area of our country is analyzed as an example, the finite analysis software MIDAS/Civil is used to build the finite element model, and spectrum method and time history analysis method are applied to the aseismic performance analysis of the high pier bridge. The effect of pier height changing and track stiffness on the seismic performance of the bridge is discussed. The main contents are as follows:In this paper, the seismic damage of bridges and seismic research situation of continuous rigid frame bridge are firstly reviewed. Then the static method, the response spectrum method, time history analysis method and stochastic vibration method are summarized respectively.The finite element model is built, and dynamic characteristics of the bridge is analyzed. The response of internal force and displacement of this bridge under the design earthquake and rare earthquake are calculated by using the response spectrum method and time history analysis method respectively, and the results are compared.Based on the results of time history analysis method, the pier ductility is carried out, and the result is discussed.The effects of different height of bridge pier on the dynamic characteristics are analyzed. And the internal force and displacement of the piers under earthquake are studied with the changing of the pier height.The finite element model of the bridge with ballastless track system is built, the effect of track stiffness on the dynamic characteristics of the bridge is analyzed as well. And the impact of track stiffness on internal force and displacement of the bridge under earthquake is analyzed by using dynamic time history method.