Longitudinal movement of a suspension bridge under train braking and its control with fluid viscous dampers
The braking behavior of trains will notably affect the longitudinal movement of suspension bridges.Therefore,it becomes imperative to delve into the longitudinal movement of kilometer-level railway suspension bridges under the influence of train braking.This study takes a long-span railway suspension bridge with a main span of 1060 meters as its research object,and explores the response characteristics of its longitudinal movement at the girder end when subjected to train braking forces and the controlling effect of a fluid viscous dampers (FVDs) by numerical simulation.Firstly,the engineering background of the kilometer-level railway suspension bridge and the finite element model established using ANSYS software are introduced.Then,the loading and solution methods for the longitudinal movement of the long-span railway suspension bridge,the finite element simulation methods for bearing friction and FVDs,and the simulation method for braking force are described.Subsequently,the effects of different braking positions and consideration of bearing friction on the longitudinal movement response of the suspension bridge are investigated.Finally,the control effect of FVDs on longitudinal movement is studied,and parameter analysis is conducted.The results show that as the braking position approaches the point where the train exits the bridge,the shape of the longitudinal displacement curve becomes more similar to a sine function.Bearing friction has a certain control effect on the displacement response at the girder end under train braking,but its control effect on the velocity response is not ideal.The utilization of FVDs effectively controls both displacement and velocity responses at the girder end of the suspension bridge under train braking.The optimal control effect is achieved when using a FVD with a damping coefficient of 2500 kN·(m/s)-α and a velocity exponent of 0.1.
railway suspension bridgetrain brakingbearing frictionfluid viscous damperlongitudinal movement