| In recent years,with the rapid development of economy and transportation in China,long-span continuous rigid-frame bridges have been increasingly used due to their excellent structural characteristics.Due to the frequent occurrence of earthquakes in China,the research on seismic performance of continuous rigid frame bridges has received more attention.This paper analyzes the applicability of the damping parameter optimization theory of viscous dampers considering the influence between the connecting end piers and the main bridge structure in bridge engineering through a continuous rigid frame bridge with double thin-walled piers and long spans with a main span of 160 meters,and analyzes the impact of dynamic water pressure on the continuous rigid-frame bridges.The main research contents are as follows:(1)The side pier and main structure of a continuous rigid frame bridge are simplified as two single degree of freedom systems in which dampers are connected in series.The motion equations of the series system under seismic excitation are established.Taking the minimum seismic response of the structure as the optimization objective,the damper parameter optimization formula considering the influence of factors such as the stiffness ratio and mass ratio of the main structure to the side pier is derived based on the Kuhn-Tucker minimum principle.(2)Through the parameter sensitivity analysis method and the introduction of the damping efficiency function,the effectiveness of the derived damper parameter optimization formula is verified.It is found that the stiffness ratio of the main bridge structure to the side pier has a great influence on the optimal parameters of the damper,and the influence of the mass ratio can be ignored.In order to dissipate the seismic energy of the main bridge structure,the upper limit of the stiffness ratio between the main bridge structure and the side pier of the continuous rigid frame bridge suitable for the installation of liquid viscous dampers is given.(3)The influence of dynamic water pressure on the seismic response of continuous rigid frame bridge under E1 and E2 earthquakes is analyzed,and the variation law of the extreme value of the key seismic response of the bridge is discussed.Under the earthquake action of E2 along the bridge direction,the viscous damper with optimized damping coefficient derived from the formula can still greatly reduce the seismic energy of the main pier,and weaken the key responses such as the internal force response of the main pier bottom,the internal force response of the pile top,the internal force response of the pier top and the displacement response of the beam end. |
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