Analysis Of Wind-induced Response On Cross-line Bridge Caused By High-speed Train Meeting

Aerodynamic problems caused by high-speed trains meeting the train at a higher speed not only impact passengers with pressure,but also generate strong pressure waves to cross-line structures.In this paper,numerical simulation method is used,and Fluent software is used to analyze and simulate the wind pressure time history and wind pressure distribution of the high-speed train meeting the bridge.To verify the reliability of the numerical simulation by comparing the wind pressure time history of the train passing through the bridge at 250 km / h with the field measured results at Dezhou East Station.The wind pressure time history curve is loaded into the Midas model of the bridge to further analyze the characteristic value and wind-induced response of the bridge.Based on the three-dimensional,viscous,unsteady,incompressible,viscous n-s equation,the k-? two equation model,establish a numerical model of high-speed train meeting bridges.The wind pressure distribution law of train wind on the bridge surface under the following three working conditions was studied:(1)different passing speeds,including 250 km / h,300 km / h,350 km / h constant velocity crossing.(2)different line spacing between trains,including 10.2 m,11.2 m,and 12.2 m.(3)different bridge heights,including 7m,8m and 9m.Through numerical simulation and analysis,the wind pressure time history curves of the bridge in the windward direction and the longitudinal direction are obtained,and the distribution law of the peak pressure is obtained.The research results show that the higher the speed of train meeting,the greater the influence range of train wind,the less obvious the effect of line spacing on the distribution of wind pressure on the bridge surface,and the lower the bridge speed,the greater the influence of train wind on the bridge.Finite element analysis software Midas is used to establish a finite element analysis model for the upper truss structure of the bridge.through eigenvalue analysis,dynamic characteristics such as shape of vibration mode,natural periodic frequency,vibration mode participation coefficient,etc.are obtained.The wind pressure time-history curve obtained by fluent was loaded on the steel truss bridge,and the dynamic response of the bridge under the wind load of passing trains was analyzed.The time-history analysis results showed that the vertical displacement of the steel truss caused by train wind was obviously smaller than that of the transverse bridge under the same running speed.At the same time,under the coupling condition of train wind load and train moving load,it is found that the influence coefficient of train moving load on bridge dynamic response is larger.With the increase of meeting speed,the transverse response of steel truss bridge is also obvious,while the wind-induced response of vertical bridge is inversely proportional to it.