Study On Corrosion Grading Standards For Parallel Steel Wire Slings Of Suspension Bridge

Suspension bridge has become an important form of large-span and modern bridge construction at home and abroad because of its simple and beautiful structure and long span.The sling is one of the main stressed components of suspension bridge.In the process of bridge operation,the problem of slings corrosion is relatively serious.This paper based on the influence of the changes in mechanical properties of parallel steel wire slings on the overall structure of suspension bridges after corrosion,experimental research,theoretical analysis and structural finite element analysis are carried out to study the changes in mechanical properties of suspension bridges after the corrosion of parallel steel wire slings.This paper based on the relevant literature of steel wire corrosion,and the experimental and theoretical research work is carried out on the basis of previous studies.The main research contents and results are as follows:(1)The corrosion mechanism of parallel steel wires and the corrosion causes of slings are summarized,which provides theoretical support for the study of slings corrosion of suspension bridge.(2)Do some experimental research about the corrosion appearance and mechanical properties of parallel steel wire.According to the results of experimental research,the forms of different grades of corrosion were summarized.Meanwhile,the relationship between the corrosion rate of steel wire and the mechanical properties of steel wire was determined according to the experimental data.(3)According to the mechanical properties of parallel steel wires with different corrosion grades obtained from the tensile test and combined with the degradation model of parallel steel wires after corrosion,the appearance corrosion classification standards of parallel steel wires were divided.And then,the corrosion classification standard of slings is studied.(4)Midas finite element modelling was established for parallel steel wire slings truss suspension bridge under different corrosion conditions.The internal force,stress and deformation of slings with different corrosion grades were studied,and the stress and deflection of suspension bridges with parallel steel wire slings and steel truss beams with different corrosion grades were comprehensively compared.The corrosion grades of parallel steel wire slings were classified according to the influence of different corrosion grades on the structural forces.(5)According to the S ? N fatigue life theory,the stress amplitude predicts the life of the slings with different corrosion grades and the conditions of slings replacement.