Reliability Analysis Of 3D Parking Garage Based On Probability Density Evolution Theory

At present,most cities use high-rise 3D parking garage to alleviate the parking problem.The high-rise 3D parking garage generally adopts a steel frame structure,which has a relatively height width ratio,no floor slabs and infill walls.It is a typical high-rise flexible structure,which is prone to overturn and instability.At the same time,there is no mature design code or regulations for the 3D parking garage in our country,and the design of the stereo garage at present stage is mainly based on structural arrangement and stress analysis.Various uncertainties encountered in the design,construction and use of the structure are not considered,so it is of great theoretical and practical significance to research the response mechanism and static and dynamic reliability of 3D parking garage with random parameters under random excitation..In this paper,the high-rise 3D parking garage of vertical lifting lot is taken as the research object,the finite element numerical model is established,and the static and dynamic reliability of 3D parking garage is analyzed by probability density evolution method.The main contents are as follows:(1)Based on the research results of reliability theory,the analysis principle and calculation steps of probability density evolution method are introduced,and MATLAB general calculation programs are compiled.Compared with Monte Carlo method,the accuracy and efficiency of probability density evolution method are verified.(2)By constructing a virtual stochastic process,the relationship between the input and output stochastic variables of the system is established,combining the results of the finite element analysis,the probability density evolution method is applied to solve the structural reliability under stochastic static loads.Finally,the different structure parameters effect on the static reliability of 3D parking structure are analyzed and compared.(3)Method with spectral representation and random functions is used to obtain simulation of non-stationary ground motion under the given power spectrum model.Iteratively fitting the average response spectrum of the sample to the standard response spectrum,all non-stationary seismic motion sample sets meeting the seisimic code are obtained.(4)The random earthquake response analysis of 3D parking structures are carried out,the structural response is substituted into the numerical calculation program of probability density evolution method,and the probability density evolution curve of the structural response is obtained,reflecting the complexity of the probability change in the state space.The cumulative distribution function(CDF)curves under different response indexes are obtained by using probability density evolution method based on generalized equivalent extreme value events,the structural dynamic reliability can be obtained according to the CDF curve.(5)The finite element model of 3D parking structures with different parameters and different forms are established,and the random earthquake response analysis is carried out respectively to obtain the change laws of the structural dynamic reliability.The seismic behavior levels of the structure are divided according to the limit value of the maximum story drift angle of the structure,the seismic vulnerability curve and earthquake hazard probability matrix are obtained by combining with probability density evolution method and the incremental dynamic analysis method,which provides theoretical support for seismic design with multiple performance levels.