Study On The Wind-vehicle-bridge Coupled Vibration Of The High Gorge Bridge On The High Altitude

Wind-vehicle-bridge coupled vibration system is a mechanical system,which regards natural wind,car and bridge as an interaction and mutual effect.As the high altitude canyon areas have the characteristics of a lot of wind,high wind speed,extremely uneven terrain and so on,piers are generally built very high.But the wind poses a greater threat to the stability of the high piers.In addition,the bridges of the high piers will produce irregular vibration in the wind,which has a very large impact on the safety factor and comfort of the passengers while the cars are traveling on the bridge.Therefore,the study of the space coupling vibration of the wind-vehicle-bridge of the high-pier bridges in the high-altitude canyon areas is of great significance to the practical engineering construction.This subject is aimed at the main bridge of the high pier bridge-Wolonggou No.4 bridge.The finite element software ANSYS is used to establish bridge model for analysising.Then the dynamic model of the space coupled vibration system of the wind-vehicle-bridge is simulated,to study further the mechanism and response of wind,vehicle and bridge coupling of vibration.The main contents of this paper are as follows:Firstly,the theoretical analysis and phenomenons of vehicle-bridge coupled vibration of simply supported beam bridges under simplified loads(vehicle loads)in classical theory are briefly introduced.In the analysis,the vehicle loads are simplified as constant force,simple harmonic force,sprung mass force and so on.Secondly,the axle car space model is established according to the movement characteristics,and the equation of motion is deduced.Then the mechanism and response of the vehicle-bridge coupling vibration according to the vibration performance are studied.Based on the dynamic analysis model established by the project(Wolonggou No.4 bridge),this paper verifies the theoretical analysis of vehicle-bridge coupling vibration.The analysis results can provide theoretical support for assessing the safety and comfort of vehicles traveling on the bridges.Again,the wind load in the static wind,buffeting force and self-excited force produced by the pulsating wind are applied together on the bridges to overall analyze the trembling effect on the bridge.By studying the nonlinear problem of wind-bridge coupled vibration,which can use the time domain and frequency domain method to analyze and explore the chattering effect on the high pier bridge in the wind field.When commenting on the safety and comfort of vehicle running on the bridge,the safety of the vehicle is firstly explored,mainly from three aspects to research of vehicle side slip,roll and side deviation.By comparing the running status of the vehicle under different vehicle speeds,the critical wind speed when the vehicle rolls on the dry,wet,ice and snow road surface are obtained,which provides protection for the safety of vehicles.And then from the characteristics of vehicle vibration and the physiological mechanism of the human body,to roundly discuss and analysis the fatigue of the passengers under the different vibration conditions.The theoretical indicators related to evaluate the smooth operation of the vehicle can be obtained,which is of great significance to guide the comfort of traffic.Finally,the established wind-vehicle-bridge coupling vibration is carried out dynamic analysis research.Based on the analysis of the coupling vibration of wind-vehicle-bridge,the Wolonggou No.4 bridge is considered as the main bridge,by comparing the characteristics of wind-vehicle-bridge coupling vibration under the different wind speeds,different vehicle models and quantities,different weather conditions and so on.The most unfavorable conditions for the operation of bridges and vehicles under various conditions are studied.The research shows: the impact of the tires on the bridge deck during the running of the vehicle(it is usually cyclical)plays a major role in the dynamic response of the bridge.The magnitude of the vibration is related to the structural characteristics of the bridge.The vibration state of the vehicle in the operation is related to the roughness of the road on bridge,thus it affects the wind-vehicle-bridge coupling vibration.In addition,the regularity of bridge motion has an influence on the impact coefficient of bridge.The influence of the wind field on the coupling vibration of the wind-vehicle-bridge is mainly caused by the chattering force generated by the pulsating wind.