Durability Analysis Of Prestressed Bridge Based On Matlab Fuzzy Neural Network

As an important engineering structure of national and regional traffic infrastructure construction,bridge plays an important role in traffic and directly affects the traffic capacity and safety of the whole road,which has economic,social and strategic significance.In recent years,the durability of bridge concrete structure has become increasingly prominent.Many existing prestressed concrete bridges have a series of problems under traffic load and external environment,such as concrete surface cracking,concrete carbonation,steel corrosion and concrete spalling,which causes cracks or rather large deflection of concrete bridges and the reduction of bearing capacity.However,the existing researches on the influence mechanism,durability evaluation system and durability improvement methods of the bridge are not mature,and the corresponding durability evaluation software is lacking.The durability evaluation of prestressed concrete bridges was studied,and the influencing factors of the durability of prestressed concrete bridges were determined in the present study.The durability evaluation software of prestressed concrete bridges was developed by using Matlab fuzzy neural network,and the durability improvement methods were put forward to comprehensively improve the durability of prestressed concrete bridges.The main contents and results were as follows.(1)The influencing factors of the durability of prestressed concrete bridges were studied.The quantitative impacts of concrete cracking under anchor,concrete surface cracks,mid-span deflection,exposed broken wires of prestressed steel strands,corrosion of prestressed steel strands,compaction of pipeline grouting,concrete surface damage,anchor deformation,anchor cracks and anchor corrosion on durability were revealed.The mechanisms of the factors affecting the durability of prestressed concrete bridges were explored.Besides,based on the characteristics of concrete cracking,the crack and deflection evaluation systems were established based on various qualitative indicators such as the relationship between the crack length,mesh crack size,crack width and the cross section,and the value of mid-span deflection.Based on the analysis of reasons for the decrease of the bearing capacity of prestressed steel strand,a pre-stressed steel strand evaluation system was established based on various qualitative indicators such as the degree of prestress loss and the corrosion potential level of steel bars.Based on the analysis of the damage form of the anchor,the anchorage damage evaluation system was established based on various qualitative indicators such as the degree of deformation,the crack length of the anchor,and the change in resistivity after the anchor is corroded.(2)The durability evaluation method for prestressed concrete bridge based on fuzzy neural network was determined,and the evaluation software of the durability of prestressed concrete bridge was compiled.The calculation results of adaptive neural network and BP neural network based on Matlab language were analyzed.With the help of Matlab fuzzy neural network toolbox,the scores were simulated by using measured data,and the difference between the calculation results of the adaptive fuzzy neural network algorithm and the BP fuzzy neural network algorithm were compared.The results showed that the fuzzy neural network was suitable for the classification of prestressed concrete bridges.(3)Improvement methods for the durability of prestressed concrete bridges were put forward from the aspects of the durability design of concrete structures,construction control,maintenance and repair.By comparing the relevant design codes at home and abroad,the design methods were proposed considering structural environment,concrete strength grade,protective layer thickness,crack width and waterproof system.The effects of concrete raw materials,concrete quality,protective layer and crack quality control on the durability of concrete structure were studied,and effective measures and suggestions for quality control during construction were put forward.(4)The durability testing method for the existing concrete structure was investigated and the basic procedures and analysis contents of the durability testing and evaluation of the prestressed concrete were put forward based on the actual engineering cases.The difficulties of protective coatings,rust inhibitors and cathodic protection in the design and construction processes were analyzed.Methods for improving the durability of concrete using protective coatings,rust inhibitors and cathodic protection were also put forward.