The Study Of Using FPS To Reinforce Existing Bridges

At present, due to the concept of a single level of defence based on intensity and flexible design method of the existing bridge fallen behind relatively, C hina has a large number of bridges which are under the situation of lacking seismic resistance. Coupled with the idea of China continent is over a plurality of seismic sections, frequent earthquakes have a huge threat to security on people’s lives and property, and the bridges which are known as the lifeline of the project play a significant role in the process of disaster relief. In view of these, seismic reinforcement for existing bridges which are lack of the seismic performance is very necessary.Research in this paper is based on the friction pendulum support which is widely uesd in foreign countries currently, and it will analyze FPS’ isolation effect on the seismic reinforcement of existing bridge. This paper takes a three-span continuous girder bridge which is located in theⅠclass site for example, use the finite element analysis software Midas civil to build three-dimensional dynamic model of the bridge. Eigenvalue analysis shows that the bridge has high overall rigidity and its modal quality focus on the first and the second modal in horizontal directio n, so the seismic reinforcement of this bridge is suitable for isolation solution. Then it use Push-over method to analyze this continuous beam bridge, according to the “08 rules” to evaluate the seismic performance of the bridge and turns out that it does not meet the requirements, so it needs to be seismic reinforced.Then it designs FPS for the bridge to replace all the original supports of the bridge and takes eigenvalue analysis, the result shows that the new bridge’s natural vibration period extended to more than three times of the original bridge. Then it analyzes the seismic effect of isolation in E1 and E2 two- level earthquake, finds that effects of internal forces of the bridge piers dropped significantly and meet the regulatory requirements; meanwhile, considering for the displacement of the bridge superstructure is too large, it sets viscous damping device so that the displacement can also be controlled. Then it proves that us ing FPS with linear damping devices together to reinforce the three-span continuous girder bridge has remarkable effect.Finally, this paper takes the original bridge model as a bench mark, adjusting the pier height to 5m and 20 m, in this way, to compare and analysis the different effect of isolation reinforcement with different height. It founds that the isolation effect of low pier bridge is relatively better.