Seismic Response And Shock Absorption Analysis Of Continuous Girder Bridge Considering Hysteretic Behavior Of Piers And Supports

Considering the nonlinear behavior of bridge piers and supports,the seismic response and tuned inertial damper(TID)damping performance of bridge structures are obviously affected.At present,most of the optimized studies on TID for continuous girder bridge are under the elastic state of pier and ignore the hysteretic performance of the support.Therefore,based on the random vibration theory,the influence of the hysteretic properties of piers and bearings on the seismic response of continuous girder Bridges and on the optimal design of TID shock absorption was studied.The main contents are as follows:(1)Taking the simplified two-degree of freedom model of three-span continuous girder bridge as the research object,the hysteretic behavior of friction pendulum support(FPS)was expressed by Bouc-Wen model,and the structural responses under stationary and non-stationary random excitation were analyzed.The results show that the hysteretic energy dissipation effect of FPS can reduce the seismic response of the structure.The effects of FPS friction coefficient and equivalent sliding radius on the structural response are revealed.(2)Based on the two-degree-of-freedom simplified model,the TID damping model was established to realize the optimal TID design under stationary random excitation.The effects of friction coefficient of FPS and equivalent sliding radius on the optimization parameters and damping performance of TID were investigated.The effects of site characteristic frequency,damping ratio and seismic intensity on the damping performance of TID are illustrated.(3)The longitudinal and transverse multi-degree of freedom models were established,and the hysteretic behavior of the pier was expressed by using the Bouc-Wen model considering the degradation effect.Through comparative analysis,the reasonableness of using the two-degree-of-freedom simplified model for longitudinal bridge damping analysis in elastic state is clarified.The effects of yield stiffness ratio,yield curvature and degradation rate of stiffness and strength on the hysteretic performance and structural response of piers were investigated.(4)Based on the multi-degree of freedom(DOF)model considering the hysteretic performance of the pier column,multiple TID optimization designs of longitudinal and transverse vibration absorption were implemented under non-stationary random excitation respectively.By comparing the TID optimization parameters and the damping effect under different optimization schemes,it is shown that the damping effect of TID will decrease after the pier bottom enters the yielding state.The influence of pier plasticity parameters on the damping performance of TID was investigated.