Study On Driving Comfort Of Long-span Cable-stayed Bridge Based On Bridge Deck Roughness

When the vehicle is traveling on the bridge, in the excitation of vibration of the vehicle engine and bridge surface roughness bridge will occur vibration which reacts to vehicle systems resulting in increased vibration. The vehicle loading effect of moving load will be larger than that of static load, what’s more the vibration will affect passenger riding comfort. As a modern bridge, large span cable-stayed bridge which has advantages of large span and small deadweight, etc becomes one of the first bridges crossing the river. Stiffness of bridge is smaller than others. Therefore, it is necessary to study the vehicle-bridge coupling vibration of the cable-stayed bridge and riding comfort. In this paper, it’s the research of the vehicle-bridge vibration of the cable-stayed bridge from two aspects:Firstly it takes the bridge structure as the research object. Moving load will have a magnifying effect on bridge---impact action which will cause a negative impact on safety of the bridge structure and durability; secondly it takes the vehicle as the research object. Excitation, such as bridge surface roughness and counterproductive effects of vibration on the vehicle and so on will affect the acceleration of vehicle in all directions(longitudinal、horizontal、vertical).Thus riding comfort of the passenger will be affected. In this paper, the main research contents are as follows:(1) It summarizes vehicle-bridge vibration study at home and abroad through consulting the documents and introduces the research methods as well as the corresponding difference from the railway bridge, vehicle bridge, etc.(2) It obtains the corresponding vehicle vibration equations through the analysis of different vehicle models (1/4 vehicle model,1/2 vehicle model, vehicle model of three-dimensional space).It chooses a three-dimensional space (7 degrees of freedom) vehicle model as the object in this paper, at the same time establishes bridge models through finite element software and then derives bridge vibration equations. At last it establishes vehicle-bridge coupling vibration equation according to the relationship between bridge and vehicle system (displacement coordination and force balance).(3) It studies the vibration response and the impact factor by different parameters (speed, weight, quality of bridge, bridge surface roughness, stiffness of vehicle suspension, damping of bridge), which shows that the speed, weight, quality of bridge and bridge surface roughness have more impaction than stiffness of vehicle suspension and damping of bridge. Besides the size of the impact factor is related not only to the fundamental frequency of a bridge specification, but also to loads and bridge surface roughness parameters, etc.(4) According to Matlab it compiles a vehicle-bridge coupling vibration software and calculates the acceleration of vehicle in all directions (longitudinal、horizontal、vertical). Selecting weighted acceleration of ISO2631 as evaluation criteria for driving comfort, it analyzes the impact on the driving comfort caused by vehicle weight, speed, road roughness and other parameters. At the same time, with the second type of excellent riding comfort for boundaries, it calculates the recommended speed that the vehicle travels on the different bridge deck, which provides a theoretical basis for crossing bridge in speed.