Preliminary Research On Seismic Performance Of Rigid-Frame Arch Bridge

Arch bridge is a popular bridge type in China, especially in west China. A lot of arch bridge have been constructed in China. Many of these arch bridges are located in high intensity seismic zone .Therefore, it is important to study the seismic performance of arch bridge. The seismic performance and damage mechanism of a rigid-frame arch bridge has been studyed in this paper.The seismic effect of different componment of seismic action has been studyed. In the near fault field earthquake zone, the vertical seismic ground motion is large. the seismic effect under vertical seismic action of a Steel Arch Bridge has been studyed in detail. As the distance from the Seismic source becomes larger, the seismic effect of the vertical direction becomes smaller. Considering the coupling of seismic effects in both horizontal and vertical directions, this paper compares the seismic response features of arch bridge structures under different vertical seismic effects. Sometimes in nearly fault position it is accompanied by foundation displacement, which can change the internal force of arch bridges with the horizontal seismic effect. therefore, taking the foundation displacement into account, this thesis analyzes and discusses the seismic damage mechanism by establishing the total cross-section stiffness and equivalent yield stiffness model.The analysis results show that vertical ground motion has little effect on axial force of arch foot,but larger effect on axial force of middle span of main arch. When the base generated 3cm relative displacement, the internal force of main arch was large as the effect of Mian Zhu Qing Ping seismic waves. So it is very disadvantageous to the bridge, once the strong earthquake coming with relative displacement of base. In addition, the results of this paper explain the seismic damage very well.