Analysis Of Bridge Vibration Response Under Random Vehicle Load Based On Measure Data

With the rapid growth of the national economy,the different degree of industrialization development leads to significant differences in the transport industry.In the area with high industrialization,the load of transport is larger,which may lead to the more load of the bridge than the design value.With the background of the national fund(No.51278134),the science and technology project of Jiangxi Provincial Department of Transportation(No.2014Y0012)and the project of Jiangxi Provincial Education Department(No.2016GJJ 160620),this paper has analyzed the vehicle load information of the expressway in Guangdong and Jiangxi Province with different degree of industrialization.The main contents of the study are as follows:(1)Based on Guangshao and Ganding's measured vehicle load information with different industrial development,this paper gets a result of the proportion of each model and the distribution of the vehicles.According to the measured information,this paper works out the CA simulation of the traffic flow.Using the measured vehicle load information,this paper works out the CA simulation program including vehicle speed,weight,lane changing and vehicle parameters in the MATLAB programming environment.In the simulation process,it is found that GuangShao highway with more overloaded vehicles under the same running state,its total load of road surface is higher than simulation results of Ganding highway and the load phenomenon is unbalanced.(2)The existing theories of vehicle induced vibration are analyzed and compared.The mid span displacement caused by different model loads on a simply supported beam is calculated.The simulation results show that the effect of the concentrated force and the moving mass is very close.The moving mass model with spring can play the role of vibration reduction,and in the range of certain stiffness,the smaller the stiffness is,the more obvious the effect of vibration reduction makes.This paper puts forward the realization scheme of the random load which is generated by the CA simulation program on the bridge of the ANSYS model.(3)Taking several typical continuous rigid frame bridge as an example and using the method of vehicle vibration proposed in this paper,the displacement impact coefficient of the bridge under the random load is closer to the standard impact factor.Under the condition of the traffic jam,the truck is in a state of large displacement compared with other operating conditions.Load limiting plays a great role on the protection of the highway bridge.The bridge displacement load after the load limiting is only a half of it before.The increase of the bridge bending stiffness will not rapidly reduce the mid-span displacement value of the bridge caused by the impact.Under the condition of increasing TMD damping,the damping effect of the bridge is obvious.In a certain range of damping ratio,with the increase of damping ratio,the damping effect is strengthened gradually.