Seismic Parameter Analysis And Optimization Of Friction Pendulum Bearing

Friction pendulum bearing is a kind of performance excellent friction energy dissipation isolation bearings,its isolation principle is through isolation and energy dissipation device on the structure of separated and extend the structure natural period of vibration and friction energy dissipation mechanism to reduce and dissipation through transfer to energy of the upper structure of the bridge,so as to reduce the effect of earthquake disaster of bridge.On the other hand,the friction pendulum bearing has a certain self reduction ability through its special arc surface structure.The excellent performance of friction pendulum bearing has aroused widespread concern and attention.Based on the continuous beam bridge,this paper studies the influence of the friction pendulum bearing on the seismic response of the bridge,and puts forward several optimization measures,the specific research contents are as follows:1,first of all listed common bridge earthquake disaster,and enumerated using seismic isolation technology of concrete bridge case reduction,of friction pendulum bearing the research status at home and abroad were summarized,the common friction pendulum system mainly surface type,groove type,surface trench mixed type.The principle and analysis method of seismic isolation are discussed,and two common methods of seismic isolation analysis,time history method and response spectrum method are discussed in detail.2,the structure and structure of the friction pendulum bearing,the form of motion,the working principle,the period of natural vibration and the characteristics of the self recovery are discussed.Based on software MIDAS to establish 13 span continuous girder bridges,the dynamic time history analysis method,select the appropriate seismic wave,the friction pendulum bearing two factors: friction pendulum radius and friction coefficient of seismic response of the bridge structure,the value of friction coefficient were 0.01,0.03,0.06,0.1,the value of the radius of friction respectively 0.5,1,1.5,2.Results found bridge structure displacement,shear force and bending moment are the dual influence of friction radius and friction coefficient,displacement and shear force of roughly with the increase of friction coefficient decreases,abutment displacement response by the influence of friction coefficient is greater than the influence of friction radius.And adopting a method of fuzzy logic control to realize the friction pendulum bearings are parameter optimization,the optimization effect when the value of R 1 to 1.5,the U value between 0.06 and 0.1 to play a better internal force and displacement of the damping effect.3,the influence of the height change of bridge pier and the change of seismic intensity on the seismic response of isolated bridge with friction pendulum bearing is studied.The pier is high as 10 m,15m,20 m,25m,30 m,respectively,to explore the conventional system and seismic response of seismic isolation system.The results showed that for the conventional system,with the increase of pier height,fixed pier pier bottom shear force and bending moment decreases gradually,pier pier bottom shear bending moment increases gradually,the gap between the two with high pier decreases gradually with the increase,in high pier is small,reducing the bearings for pier bottom shear force and bending moment of the reduction amount is large,and the damping effect is obvious,and in the pier high is high,reducing isolation bearing up to the damping effect is not obvious,so in the pier high is high,FPS bearing should caution.And explores the seismic wave intensity and frequency spectrum characteristics of earthquake on the seismic response of the bridge effect.The results showed that the different spectral characteristics of the vibration input caused by conventional system and reducing isolation system with different internal force and displacement response,seismic spectral characteristics of different will affect isolation system internal force and displacement of the damping effect,different spectrum characteristics of seismic wave caused by the FPB supports lag back energy dissipation capacity gap.The conventional system and the FPB reducing the internal force and the displacement of the isolation system are with the increase of seismic wave amplitude and generally showed a linear growth,FPB supports the displacement and internal force of the damping effect with seismic wave amplitude increases slightly with decreasing trend.4,Two kinds of optimization measures based on friction pendulum bearing are put forward.Combined measures of friction pendulum bearing and viscous damper.The results show that the viscous dampers and friction pendulum bearings used alone can be effective to reduce seismic response of the bridge,friction pendulum bearing's damping effect is better than that of viscous damper,the common use of them reasonably can further improve the bridge seismic performance.Shall be of viscous dampers and friction pendulum bearings are arranged in such a way that the attention,if both improper location will increase the seismic response,does not affect the seismic performance of the play,resulting in further economic waste.The other is the special friction pendulum structure transformation,and the steel wire rope.The results show that using the damping measures can reduce the mutual displacement between the beam and the lower part of the structure,to prevent the bridge superstructure impact between damage and the aseismatic structure will increase piers by force,by using appropriate rope parameter K value and U value can reduce the increase of pier forces.