Probability Distribution Analysis Of Passenger Car’s Sizes And Loads In The Design Of Mechanical Parking Garage

The mechanical parking garage has the advantage of small occupying area and large number of parking spaces.It can effectively alleviate the intensive situation of city parking.Nowadays,mechanical parking garage has increasingly become an essential infrastructure for urban development.Parked passenger cars sizes and loads must be firstly determined when designing a mechanical parking garage.The adoption of the vehicle sizes and loads investigated before 1998 in current garage design codes,which is not fully consistent with the present situation,results in the problems that parking space sizes and design loads value in some garages are too small.The former causes the parking space difficult to park and vacant,while the latter may cause the insufficient bearing capacity of garage load-bearing members.In this dissertation,based on current passenger car parameters,by use of mathematical statistics principle and finite element analysis method,the sizes and loads of the passenger cars to satisfy the current parking needs when designing a mechanical parking garage are studied.The main research contents of this dissertation are as follows.Firstly,the sizes（length,width,and height）,curb weight,wheelbase,track,and sales volume data of three types of passenger cars,sedan,SUV（Sport Utility Vehicle）,and MPV（Multi-Purpose Vehicle）,sold in the Chinese market from 2009 to 2020 are collected.There are 7193 sets of sizes data,6689 sets of curb mass data,7150 sets of wheelbase data and 5722 sets of track data.Secondly,the probability distribution models of the sizes are determined,with different probability distributions used to fit and analyze the size data.According to the 95%guarantee rate and the actual situation of the vehicle models,the recommended sizes for different combinations of sedan,SUV,and MPV are given,respectively.Thirdly,the curb mass plus 50 kg of the luggage mass is taken as the mass of the passenger car parked in the garage,and then multiplied by the gravitational acceleration to get the load of the passenger car.Using the probability analysis method,the probability distribution models of passenger car loads are determined,and the recommended loads for different combinations of sedan,SUV,and MPV are given.Finally,after determining the position of the most unfavorable load of the passenger cars,the calculation method of the equivalent uniform loads of the passenger cars is established according to the principle of equivalent maximum moment.The equivalent uniform loads of the vehicle plate under the three boundary conditions（four sides simply supported,two long sides simply supported and the other two free,and two short sides simply supported and the other two free）are calculated by ABAQUS.The following conclusions are drawn.（1）The sizes of sedan and SUV obey the t Location-Scale distribution,and the sizes of MPV obey the mixed Normal distribution.The sizes of the vehicles given in the current codes are 2.91%～22.50%less than the values recommended in this dissertation.（2）The loads of sedan and SUV obey the Lognormal distribution,and the load of MPV obeys the mixed Normal distribution.The vehicle loads given by the current codes are 6.4%～30.2%less than the value recommended in this dissertation.（3）The wheelbase and track of sedan and SUV obey the t Location-Scale distribution.The smaller the values of the wheelbase and track of the passenger car are,the more unfavorable the load on the vehicle plate is.（4）The equivalent uniform load of the passenger car is the largest under the condition of four sides simply supported,and the maximum equivalent uniform load of the sedan,SUV,and MPV is 2.75 k N/m~2,3.11 k N/m~2,and 3.64 k N/m~2,respectively.