Numerical Simulation of Tornado Loads on a High-speed Railway Continuous Girder Bridge

To investigate the characteristics of the tornado load on continuous girder bridges of high-speed railway, this study simulated the tornado load mentioned above by computational fluid dynamics method. Specifically, using the Ward-type tornado simulator as the physical prototype, a numerical model was built based on similar configuration and equivalent substitution principles. The numerical wind field was then validated by a reference experiment conducted in a Ward-type simulator. By taking a long-span high-speed railway continuous girder bridge as the engineering background, a three-dimensional model of the bridge was laid in the center of the numerical tornado field. The wind pressure characteristics of the bridge were investigated. The results show that the numerical model is able to simulate the essential characteristics of a tornado field. When a tornado strikes the high-speed railway continuous girder bridge, the vortex changes significantly because of the interference of the girder and piers. A large core radius is found underneath the main girder, forming an area of high wind speed. A significant discrepancy in the wind pressure is obtained on the surfaces of the bridge, with difference between the positive and negative wind pressure appears being approximately 2. 5 times that of the negative peak pressure. The negative pressure appears in a small area of the middle span of the main girder. The negative pressure value on the top of the girder is lower than that on the side and the bottom. The maximum positive wind pressure appears on the windward side of the end of the girder. The windward sides of the piers also experience a high positive wind pressure. The highly unbalanced wind loads mentioned above should be considered in designing high-speed railway continuous girder bridges. © 2021, Editorial Department of China Journal of Highway and Transport. All right reserved.