Study On Seismic Performance Of Self-reset Bridge System With Viscous Damper

In recent years,earthquakes occur frequently around the world,once the bridge structure is damaged,it will cause serious economic losses.A lot of earthquake damage indicates that the Bridge longitudinal damage under earthquake is often more serious,is the main problem in the field of bridge seismic.In this paper,a cable-stayed bridge is taken as the background project,and the finite element model of the whole bridge is established on the Open Sees analysis platform to study the modeling process,material constitutive and seismic response of the bridge.The research contents are as follows:(1)On the basis of the bridge section and material characteristics provided by Midas Civil,the numerical model of the whole bridge is established through the Open Sees platform.Then,the period and vibration mode of the model in the two softwares are compared to verify the rationality of the model.(2)The structure,basic damping principle and fluid medium of viscous damper are briefly introduced,and choose the appropriate damping parameters and restoring force model to build viscous damper numerical model.The finite element model of rocking self-centering(RSC)pier is established by selecting appropriate material parameters in Open Sees analysis platform.(3)Taking the original bridge as model 1,adding longitudinal viscous damper between auxiliary pier-beam and tower-beam as model 2,adding viscous damper and designing auxiliary pier as RSC pier as model 3.Based on different working conditions,establish the finite element model of cable-stayed bridge.(4)Five sets of near-field pulse-type seismic waves were selected from the Pacific Earthquake Engineering Research Center(PEER)strong-motion database,and nonlinear dynamic time analysis was performed on each model by selecting appropriate intensity indexes and extracting parallel components of seismic waves to study the seismic response of key parts of the cable-stayed bridge under different seismic waves.(5)The structural response of the key parts is used as the control target,and the control effects of the self-relieving damping system on the peak displacement and post-earthquake residual displacement under the effects of design earthquake,rare earthquake and giant earthquake are analyzed.The characteristics of the hysteresis curve of the viscous dampers and the change law of the cumulative energy dissipation curve in each model are analyzed to determine the energy dissipation effects of the viscous dampers in the self-relieving damping system.The results show that the placement of viscous dampers between the pier beam and the tower beam can effectively reduce the seismic response of the bridge,but it will cause the residual displacement at the top of the auxiliary pier to increase.The replacement of the auxiliary pier to the RSC pier can effectively reduce the residual displacement of the pier,reflecting good self-centering performance.