Study On Seismic Response Reduction And Isolation Of Curved Beam Bridge

With the development of transportation, especially the rapid development of urban viaduct network, more requirements on the function and outlook should be fulfilled in the bridge design. These bring out the wide use of curved beam bridges. But there is still a lot of work to do to understand the seismic response specialty of curved beam bridges, the application of isolation bearing in curved beam bridges and many factors related to isolation of bridges, which has the important practical significance for the curved bridge anti-seismic design.In this paper, based on common curved beam bridge, four models of 3-D finite element with ANSYS are set up to analyze seismic response laws and the application of isolation bearing. Each model's radius varies from 100 meters to infinite. The emphasis is as follows: modal response of different curvature bridge; the relationship between the variety of the curvature and the seismic response of the bridge, the relationship between the variety of the isolation bearing and the seismic response of the bridge; seismic response variety of the bridge applied with isolated bearing in dissimilar seismic excitation; the performance of lead-rubber bearing and their fluencies on the seismic response of the bridge structures which are equipped with the LRB. Base on the analysis, some valuable conclusions are acquired.The modal response of the curved beam bridge has very close relation with the supported bearing and connected rigidity, and varies remarkably in smaller curvature. It is basically invariable in bigger curvature. Different modal of identical model maybe have different rule of variation. The maximum seismic response of the curved beam bridge has very close relationship with the curvature and supported bearing and it varies more obviously when curvature is relatively small. To analyze seismic response of girder bridges under the effect of lateral seismic wave, a 3-D finite element model of whole bridge should be established, especially when it comes to the curved beam bridge. The seismic response of the structure is very sensitive to the properties of the earthquake waves and the discreteness of the result is very obvious among different earthquake waves. So many earthquake waves with similar site condition should be chosen as far as possible for the structure design and the maximum values of the seismic response should be picked as the design parameter for safety.By setting lead-rubber bearing, the natural frequency and damping of the structure are changed to reduce the seismic response of piers. Within the extent of elasticity, the displacement of the beam is reduced with the increase of the yield stress, but the natural frequency may be included in the resonant area or nearby after setting lead-rubber bearing. The possibility of this situation should be considered in design. Within the extent of elasticity, the seismic response rule of shear force and moment at the bottom of the pier is basically the same. As the yield stress of LRB is increased, the seismic response is thereupon increased.