Research On Reliability Of Prestressed Concrete Continuous Beam Bridge Based On Neural Network Algorithm

In service,the prestressed concrete continuous box-girder bridge will bear various loads and be affected by the environment,chemical erosion,and aging of structural materials.Therefore,the bridge structure components will appear different levels of damage and defects,resulting in insufficient bearing capacity.It will affect the regular use and even lead to a series of safety accidents.Furthermore,carrying out scientific,reasonable,and accurate reliability analysis and residual life assessment of the existing bridge structures.It can guide the corresponding maintenance and reinforcement.So,it will reduce the safety hidden troubles effectively and produce lots of economic benefits.In this paper,the reliability of the prestressed concrete continuous box-girder bridge is taken as the important research object.The GA-BP neural network model is used to established the limit state function of the structure.It also consider the main factors that affect durability.Then,Monte-Carlo method is used to calculate and analyze the reliability index and failure probability.Furthermore,in this paper,MATLAB language is used to program the reliability index and failure probability of the prestressed concrete continuous box-girder bridge.And the variation regularity that the reliability of the prestressed concrete continuous box-girder bridge is obtained.This paper also reveals the time-varying regularity that the reliability of the existing prestressed concrete continuous box-girder bridge.Then,this paper establishes and perfects the methods for the reliability assessment of the prestressed concrete continuous box-girder bridge.It has specific technical innovation and practical engineering guiding significance.The main contents of this paper are as follows:(1)Based on the theory of BP neural network and the realization of genetic algorithm optimization,the GA-BP neural network model is established.This model is more efficient,more accurate,and more convenient to established the limit state function of the structure.(2)The finite element model is created by Midas Civil.The probability variation models such as concrete weight,vehicle load,concrete strength,section area of prestressed steel strand and strength of prestressed steel strand are established by analyzing of the various factors that affect the service process of the bridge.And this paper analyzes the regularity of time-dependent variation.(3)The program that calculating reliability index and failure probability is programmed by MATLAB language after obtain the limit state function of the structure.Applied to a practical project,the reliability indexes of the prestressed concrete continuous box-bridge under the limit state of normal service and bearing capacity are analyzed and calculated respectively.And compared with the target reliability,this method is used to analyze and predict the remaining life of prestressed concrete continuous girder bridges.