The Ship-bridge Collision Analysis Of Long-span Cable-stayed Bridge And The Performance Study On Anti-collision Device

With the development of land and water transportation in China,ship-bridge collision accidents are increasing,causing a large number of casualties,economic losses,environmental damage and disruption of traffic lines,and posing a huge threat to the operation safety of the bridge and the sailing safety of ships.At present,research on ship collisions of long-span cable-stayed bridges is incomplete,and there are some disadvantages of traditional anti-collision devices.Therefore,in combination with the Lingang Yangtze River Bridge project,the ship-bridge collision analysis of the longspan cable-stayed bridge and the performance study of the anti-collison device are carried out through numerical simulation.Firstly,the theory research of ship-bridge collision was summarized and the law of impact force and energy conversion of ship-bridge collision system was obtained.According to the navigation standards of the bridge area,the relevant parameters of ship collision were determined.According to the structure of the bridge tower and the ship,the nonlinear finite element analysis software ANSYS / LS-DYNA was used to simulate the process of collisions and side collisions of 5000 t and 8000 t ship.The change laws of impact force,energy,pylon displacement and stress were obtained through analysis.Based on the time history analysis,the process of ship-bridge collision was divided into two stages: loading and unloading,and the characteristics of these two stages were summarized.Secondly,the effects of ship impact speed and ship tonnage on impact force and energy are studied.Combining empirical formulas and numerical simulation methods,the curves and the relationship formula of force-speed,force-tonnage,energy-speed and energy-tonnage were obtained.The relationship between the impact force and energy and the ship’s impact velocity and tonnage are all positively correlated.An empirical formula is used to help explain the rationality of the simulation.Then,on the basis of the traditional steel box,combining the advantages of light weight,high strength and corrosion resistance of FRP,a self-floating steel-FRP box type anti-collision device(referred to as steel-FRP box)was proposed,and its structural design was introduced.At the same time,the collision model of the shipbridge-anti-collision device was builded.Through numerical simulation,the shipbridge collision analysis is performed on the working conditions of no anti-collision device,installing steel box and installing steel-FRP box.The effect of reducing structural damage and other aspects proves the anti-collision effect of the device.And through comparison,we also get the advantages of steel-FRP box compared to traditional steel box in protecting bridges and ships.Finally,the parametric influence analysis of the steel-FRP box device is carried out.The three aspects of impact force,energy absorption and specific energy absorption were selected to evaluate the anti-collision performance.Using the method of controlling variables,the effects of the distribution of the thickness of steel and FRP,the impact speed of the ship,and the tonnage of the ship on the anti-collision effect of the device were studied.It is obtained that when the thicknesses of steel and FRP are8 mm and 4mm respectively,the impact speed is 5m/s～6m/s or the tonnage of ship is3000t～5000t,the collision resistance of steel-FRP box device is better.