Research On Non-motor Vehicle Load Of Slow Traffic Bridges Based On Cellular Automaton Modeling

With the development of urban slow traffic,non-motor vehicle bridge emerges at the historic moment.The safety,applicability and economy of the non-motor vehicle bridge are closely related to the design load.However,the research on the specific non-motor vehicle load of non-motor vehicle bridge is very scarce.In view of this,in this paper,the characteristics of non-motor vehicle load were analyzed by field investigation method and probabilistic mathematical statistics method,and the cellular automata theory was used to carry out the simulation of non-motor vehicle load flow based on the survey data.On the basis of this,the load effect of the slow traveling system bridge under the actual non-motor vehicle load is studied,and the non-motor vehicle design load model is established,which can provide reference for the relevant design and specification formulation.The main research methods and conclusions are as follows:(1)According to the previous research results and the research content of this paper,the theory and method used in non-motor vehicle load simulation in this paper are determined.The parameters of non-motor vehicle traffic flow studied in this paper are instantaneous velocity and surface density,and the survey method is photographic observation method at high ground.The parameters of vehicle weight are picked up by small loadometer.The non-motor vehicle load flow model established in this paper is determined to be multi-lane cellular automata model.(2)The basic information of non-motor vehicle traffic flow,including non-motor vehicle type,speed,vehicle weight,traffic density and other parameters,was obtained by field investigation method.According to the collected data,the probability distribution model of nonmotor vehicle traffic flow was studied by mathematical statistics and probability theory method.The results show that the vehicle speed,vehicle weight,traffic density and sway velocity of non-motor vehicles do not reject the normal distribution mode,and have a low test error.(3)The Cellular Automata Non-Vehicle Load Flow Simulation Method is established.According to the traffic characteristics of non-motor vehicles,the model can accurately simulate the cycling behavior of non-motor vehicles by improving the cell size,boundary conditions and lane changing rules.When the non-motor vehicle load is integrated into the nonmotor vehicle traffic flow model of cellular automata,the influence line loading method is introduced and implemented by the program.For non-motor vehicles cellular automata simulation method are verified and the results showed that both traffic flow characteristics and load characteristic,the simulation results with the measured results have good experimental data,this model can well actual non-motorized traffic simulation analysis,and make the precise calculation of non-motor vehicles under actual load effect.(4)Based on Multiple Cellular Automaton Simulation Method,analyzed the different span and different width of slow system structure response of the bridge under the loads of nonmotor vehicles(midspan moment,pivot shear),based on the reliability theory and the principle of equivalent load effect,to calculate the load effect design reference period 0.95 points value,maximum value distribution function and its conversion to the corresponding non-motor vehicles load standard values.By analyzing the relationship between the standard load value of non-motor vehicle and the bridge length and width,the calculation formula of the standard load value of non-motor vehicle design is fitted,which can provide reference for the structural design and optimization of non-motor vehicle bridge.