Random Finite Element Analysis Of Construction Error Of Cantilever Assembled Rigid Frame Bridge

For prestressed concrete rigid-frame bridge at cantilever construction method,the continuous rigid frame bridge in construction of the cantilever construction method is adopted,in the process of its construction,considering the change of the cantilever length,the diversity of the characteristic of structure parameters and load will influence on the state of bridge,this paper introduces these uncertainties in the reliability analysis,reliability analysis method is used to describe the bridge safety of the whole construction period.The ability of SVM algorithm to process high-dimensional data and its excellent learning ability of small samples have unique advantages in the field of reliability research.This paper takes the long span part of the South Fourth Ring Viaduct as the engineering background,and mainly carries out the following work:(1)According to the requirements of code and site construction,based on the reliability theory of structural system and the theory of support vector machine,this paper puts forward the hypothesis that stress and line shape are taken as the characterizing factors of reliability calculation in the whole process of construction.(2)The stress control function and the elevation control function are established.The finite element model of the whole construction process is established by using ANSYS and MIDAS respectively.The stress and deflection of the whole bridge are calculated and analyzed.(3)Based on support vector machine(SVM)theory is put forward the construction of prestressed concrete rigid-frame bridge reliability index of the whole process flow,and write the corresponding reliability algorithm in MATLAB procedures,using ANSYS to produce sample points,and then determine the method of parameter optimization,the corresponding support vector machine(SVM)model is established,and calculated for each construction stage of free end under different deflection deviation corresponding reliability indexes,it is concluded that the whole construction process to assemble error and precision of the final closure allows for recommended value.(4)With tension control stress and young’s modulus of concrete and steel strand elastic modulus as the main random factors,through orthogonal experiment,the method of construction and parameter sensitivity analysis,calculated the variation of the random parameters in different role in the various stages of the reliability of the control indicators,it is concluded that the random parameters to affect the sensitivity of the reliability of prestressed concrete rigid-frame bridge construction parameters,cantilever construction of prestressed concrete rigid-frame bridge to provide important technical support.