Vibration Test And Simulation For Traffic Loading Of Urban Roads

The vibration issue of roads and surrounding structures induced by urban traffic has always attracted widespread attention from researchers in the industry.The amplitude of structural vibration is small,but it lasts longer.And it has some influence on the health of body and the safety problem of the building structure itself.Therefore,the research on pavement vibration under traffic loads has important scientific significance and engineering application value.In order to truly simulate the vibration acceleration time history of pavement under traffic loading,this paper carries ou t traffic investigation and vibration test on the municipal road near the fair of Wanbo in Guangzhou Panyu District.The impact of vehicle speed,vehicle model and traffic flow on pavement vibration is analyzed,and the vibration acceleration signal of pavement is simulated.Using vibration acceleration signal as input,dynamic time-history analysis of underground space structure is carried out.The specific research is as follows:(1)The all vehicle models are divided into four categories: cars,vans,tru cks and buses,and a simple discretization of the sampled data of the vehicle flow is done.Taking account of the time series as a variable,the number of specific vehicle models is counted every 20 minutes.The statistic data of the traffic flow is further analyzed,and the Gaussian mixture model is established.the mean and variance of four kinds of vehicle models are gained,and the parameters of the probability distribution function are calculated by the measured data.With the aid of MATLAB data processing technology,the traffic flow is simulated,and the corresponding random number is generated by the probability distribution function.Setting the corresponding confidence intervals,considering the interval of the investigated data,eliminating the ma ximal and minimum value of lower occurrence probability,the traffic flow spectrum according to the actual situation can be obtained.The distribution function of stochastic process is fully considered in the simulation of traffic flow,which provides a re liable theoretical basis for the simulation and compilation of subsequent load spectrum.(2)The vertical vibration acceleration time-history data of the pavement under the sole vehicle-model and mixed vehicle-model action is investigated.Combining the power spectral density(PSD)of the vibration signal,the data are analyzed separately from the time domain and the frequency domain.Introducing the method of artificial simulated seismic wave time-history(Triangle series Superposition method),utilizing Fourier transform,the simulation program is compiled by MATLAB platform and the vibration acceleration time-history of pavement which possessed the similar power spectral density and amplitude is generated.Combined with the distribution function of the traffic flow,the model of vibration acceleration time-history of pavement under mixed traffic flow is established.The vibration acceleration time-history of the pavement under the mixed vehicle-model action is simulated in 20 minutes,which compared with the actual measured acceleration time-history data.(3)Using finite element analysis software(ANSYS),the simplified underground space structure is analyzed by the actual measured and the simulated acceleration time-history,and the vertical displacement time-history of the mid-span Node is obtained.The results show that the maximum vertical displacement of the node is not extremely different under the action of the actual measured and simulated acceleration time-history respectively.It also shows that the simulated acceleration time-history and the measured acceleration time is extraordinary close,and the precision is better.It can be used to analyze the time history of structure.