Analysis Of Isolation Performance Based On Friction Pendulum Bearing For Urban Viaduct

With the development of economy and society,urban traffic congestion is increasingly aggravated,the emergence of viaducts has greatly cushioned the pressure of urban traffic.At present,urban viaduct has gradually become a key project of urban infrastructure construction.In order to ensure the performance of Viaduct under strong earthquake,it is necessary to study the feasibility and applicability of friction pendulum bearings applied to seismic isolation of urban continuous girder bridges,this paper studies the isolation performance of friction pendulum bearings on a section of viaduct bridge in Zhengzhou city.Base on the Midas Civil software,the three-dimensional finite element model of the bridge structure is established.The dynamic characteristics and seismic response of bridges with different isolation schemes are stduied though nonlinear time-history analysis method.The effects of design parameters,pier height,span,bidirectional seismic action and other factors of friction pendulum bearings on the performance of bridge isolation are studied,The main conclusions are as follows:(1)The friction pendulum bearing can prolong the main natural vibration period of urban viaduct and reduce the dynamic response amplitude of piers,when the frictional pendulum bearing is mixed with other supports,the frictional energy dissipation capacity of the frictional pendulum bearing may not be fully developed.(2)The isolation performance of friction pendulum bearings increases first and then decreases with the increase of dynamic friction coefficient.The frictional pendulum bearing exists best dynamic friction coefficient 0.04.With the increase of slideway radius,the isolation performance increases first and then tends to be stable.In order to exert the isolation and energy dissipation capacity of friction pendulum bearings most effectively,the comprehensive benefit is the highest when the slideway radius is 3 m.(3)The pier height has a great influence on the isolation performance of the friction pendulum bearing.When the pier design height is too high,the friction energy dissipation capacity of the friction pendulum bearing completely fails.With the increase of bridge span,the natural vibration period and seismic response amplitude of equal-span bridges are basically stable and have little change.(4)When considering bidirectional seismic action,the seismic response amplitude of piers and friction pendulum bearings is higher than that of unidirectional seismic action.If the bidirectional seismic effect is not considered,the isolation performance of friction pendulum bearings will be overestimated.