Transverse deflection-span ratio suggested value of an urban rail transit bridge based on a wind-vehicle-bridge system

The limit value of lateral deflection to span ratio is 1/4 000 in the code for the design of an urban rail transit bridge; however, some built bridges do not meet the limits in the code but can also operate safely. An urban rail transit bridge is limited by bridge width. Its transverse stiffness is relatively small. For long-span urban rail transit bridges, if they are still designed at 1/4 000, construction costs may increase. This paper took the actual bridges of five engineering projects as the background and used the independent development software BANSYS to analyze coupling vibration of a wind-vehicle-bridge system. The transverse stiffness of the bridge was changed by changing the section transverse moment of inertia of the main beam, and its influence on vehicle driving was analyzed, and the influence of factors such as vehicle type, bridges type and span, different safety index were analyzed, the lateral stiffness limit was obtained when the vehicle safety index exceeded the limit. The bridge model was used at this condition to obtain the deflection span limit under the effect of the vehicle's lateral oscillation force and wind force. The results show that under the effect of the vehicle's lateral oscillation force and wind force, when the value of the transverse deflection-span ratio for urban rail transit bridge is not more than 1/2 500, driving safety can be guaranteed when the wind speed is 25 m/s and the speed is not more than 80 km/h. © 2020, Editorial Office of Journal of Vibration and Shock. All right reserved.