Research Of Real Earthquake Ground Motions Selection For Performance-based Highway Girder Bridge Seismic Evaluation

In the highway system of our country, the largest number of bridges is girder bridge. Girder bridges were most seriously damaged in the previous earthquakes, hampered earthquake relief, increased the secondary disasters. The technical condition of some girder bridges has become poor after operating for many years. This leads to a serious shortage of seismic ability and the bridges can be easily damaged in strong shocks. Regular seismic performance evaluations of highway bridge and seismic reinforcements depend on the evaluation results can improve seismic safety of bridges. However, there are neither relevant standards nor mature evaluation methods to follow in our country at present. Moreover, the related research abroad can not be directly used because of the significant differences of bridge structure and the standards for bridge seismic design. Therefore, expanding the research of highway bridge seismic performance evaluation methods is urgently needed.Performance-based earthquake engineering(PBEE) based on total probability theorem has been internationally recognized as the future direction of development of structural seismic design theory. And it has been successfully applied to seismic design of bridges. Seismic vulnerability analysis is the core component in PBEE theory. It can not only be applied to new bridge seismic design, but also can be applied to seismic performance evaluation of bridges that have been built. This paper takes the girder bridge as research object, applies the bridge seismic vulnerability analysis theory to the seismic performance evaluation system of highway girder bridge, especially in the detailed evaluation stage. Seismic vulnerability analysis theory is based on nonlinear dynamic time history analysis method. The key problem met in the process of seismic vulnerability analysis is the selection of real earthquake ground motions. The main work of this paper includes:1. The research results of highway bridge seismic performance evaluation at home and abroad are reviewed comprehensively.2. Apply the bridge seismic vulnerability theory to the highway bridge seismic performance evaluation system, especially in the detailed evaluation stage.3. Study the effect of probability distribution characteristics of earthquake ground motions response spectrum, such as the mean, variance and the type of probability distribution to bridge seismic vulnerability analysis.4. Put forward a selection method of real earthquake ground motions for bridge seismic performance evaluation based on seismic vulnerability.