A Preliminary Analysis Research Of Seismic Isolation Design For Continuous Girder Bridge In Severe Earthquake Region

The seismic performance of structures can be improved significantly via seismic isolation. To date, there are several hundred bridges that have been applied to the technologies of seismic isolation in New Zealand, Japan, Italy, the United States and other countries, some of which have survived in real earthquakes successfully. In contrast to that, such bridges can't be found in China and research on theory of seismic isolation for bridges are also scarce. In order to popularize the applications of seismic isolation in bridges and expedite our seismic design level, it is necessary to carry out considerable research on technology of seismic isolation. In view of the stress characteristics of continuous girder bridge which is just setting one fixed support causing the continuous girder bridge in adverse state under earthquake action, so it is in particular necessary that make a special study on the technology of seismic isolation of the continuous girder bridge.Systems analysis several earthquake-reduction and seismic-isolaton devices, such as Spherical bearings; Friction Pendulum System; Viscous damper; Lead-rubber bearings. According to the Guidelines for Seismic Design of Highway Bridge, combing with north- continuous girder bridge approach of Xia-zhang long-span bridge, which is studied seismic isolation under severe earthquake, this paper has studied some relative research work as follwings.First, The characteristic and origin of the harmness of bridge structure is analyzed. A brief summarizing of some earthquake-reduction and seismic-isolaton devices and the seismic design mothed. Depict the signifinance studying of the technique of seismic isolation .Second, introduced the mothed of analysis and modeling of the bridge with earthquake-reduction and seismic-isolaton devices. The conception design of the shock absorption bridge is depicted. A brief summarizing of detail conformation design of the shock absorption bridge are introduced.Thrid, by the computer program SAP2000, three-dimensional finite element model of the north-bridge approach of Xia-zhang long-span bridge is simulated. Simulated model is mostly emphasized on in the model ,which should be the stiffness,mass and boundary condition of the bridge in the fact.Fourth, according to the characteristics of north approach of Xia-zhang large bridge, the schemes of installing earthquake-reduction and seismic-isolation devices of the north-bridge approach of Xia-zhang long-span bridge are ensured by comparion of all schemes,. The analysis results indicate that the damping and isolation effect of the earthquake-reduction and seismic-isolation devices can be up to more than fifty percent.Fifth, in this paper, the main design parameters of viscous damper and lead-rubber bearings are discussed. The earthquake-reduction effectiveness of the main design parameters of viscous damper and lead-rubber bearings are studied. The conclusions can be used as reference to earthquake-reduction and seismic-isolation design of the north-bridge approach of Xia-zhang long-span bridge.