Research On Vibration Reduction Of Rocking Column And Its Control Method

In the bridge structure,the bridge pier is an important component of the bridge structure.Its main function is to bear the load from the upper structure and transfer the load to the foundation through the ground.When an earthquake occurs,if the lateral displacement of the bridge pier structure is too large,it will cause the overall destruction of the bridge structure.In order to solve this problem,the author proposed a swing column energy dissipation device based on the theory of structural vibration control to improve the lateral movement stiffness and energy dissipation capacity of the bridge pier structure,thereby effectively protecting the bridge structure from damage under external excitation.The civil engineering vibration control theory is developed after the traditional seismic design method.Its main control idea is to use the control device to generate the control force to resist the vibration response of the structure.Vibration control mainly includes passive control,active control,semi-active control,hybrid control,and intelligent control according to the different ways in which the control device generates control force.Each control method has its own characteristics.This paper mainly studies the energy consumption and shock absorption performance of the swing column device in three aspects: passive control,active control and intelligent control.In order to establish the motion equation of the pier structure,the vibration control model of the pier structure is established by using the theory of low element modal model proposed by K.Seto,and then the dynamic equation of the pier structure with swing column is established by using the relevant dynamic modeling method.Firstly,the active control of the swing column is studied.The active control algorithm(LQR algorithm)is used to design the brake in the swing column device.Then,the dynamic analysis of the bridge pier structure with swing column is carried out under the condition of seismic wave as external excitation load,and the vibration reduction mechanism of the swing column is analyzed in detail.Through the case analysis,it can be seen that the reason why the swing column device can reduce the vibration is that it provides additional stiffness and additional damping to the building structure.Secondly,in order to overcome the disadvantage of consuming a large amount of external power in the active control method,a current controller is designed by using fuzzy logic algorithm,and then the brake in the swing column device is replaced by magnetorheological damper for intelligent control of the pier structure.Through the analysis of the case,it can be seen that the energy dissipation performance of the swing column device under the fuzzy control is better than that of the active control.Finally,the advantages and disadvantages of active control and intelligent control are summarized,and the energy dissipation performance of the swing column device under passive control is further studied.In order to realize the passive control strategy of the swing column device,the tuned viscous mass damper is used to replace the brake in the swing column device.Based on the modal analysis method and fixed-point optimal design theory,the swing column and tuned viscous mass damper are designed.Through the analysis of the case,it can be seen that the rocking column device designed by the fourth-order mode has good energy dissipation and shock absorption performance.