The Operational Safety Of Subway Trains On Large Steel Truss Arch Bridge Under Cross Wind And Rain

Nowadays, with the development of China’s transportation infrastructure, the influence of wind and rainfall to vehicles in operation attracted more people’s attention. In this dissertation, the safe operation of subway trains affected by wind and rainfall is studied. Through wind tunnel test and theoretical analysis, the overturning wind speed of subway trains in different wind and rainfall conditions is discussed. The following works has been carried out:1. Taking a large steel arch bridges as an example, subway trains are supposed to move on this bridge. Through the wind tunnel test, the aerodynamic coefficients of subway trains under different wind angles of attack on side and middle span are obtained. The effect of bridge ancillary facilities to the aerodynamic coefficients is studied.2. The safety operation of subway trains on bridge in crosswind is investigated. First, through theoretical derivation, equilibrium equation of critical overturning condition is established, the relationship between wind speed and train speed is obtained. Then by reference to a Chinese railway report, the formula of train speed and aerodynamic coefficient is developed with the results gained from the wind tunnel test. Finally, the critical overturning wind speed of subway trains are given by solving the equilibrium equation.3. The safety operation of subway trains on bridge in both crosswind and heavy rain is investigated. First of all, the properties of raindrops including the raindrop size, the terminal velocity of raindrops and the distribution of raindrops are analyzed. Then characteristics of wind-driven rain are investigated with theoretical analysis, the density variations of the air are discussed. Impact pressure of wind-driven rain act on the subway train is calculated and is added into equilibrium equation of critical overturning condition. Finally, the critical overturning wind speed of subway trains with the effect of wind and rain are calculated. This paper is instructive to the design and safety running of other similar situations.