Research On The Effects Of Corrosion Of High Strength Steel Wire Mechanics Performance

The corrosion of steel bars is a common phenomenon in the building structure, which not only affects the durability of the structure, but also greatly reduces the bearing capacity and stability of the structure. In our country, a lot of researches on the material properties and mechanical properties of corroded steel bars have been done, and some research results with practical application meanings have been made. With today’s rapid development of large span bridges,high strength steel wires which used as the main stress components in cable-stayed bridges and suspension bridges are becoming more and more widely used,and higher requirements on its comprehensive performance are put forward. However, the high strength steel wires wrapped in the PE jacket are also faced with the risk of being corroded. Once the corrosion is too serious, the steel wire ropes can not resist the effect of external load, it may cause a devastating damage. Therefore, based on the research methods and results of ordinary steel corrosion, the methods that accelerate the corrosion of corroded high strength steel wires and the changes between the mechanical properties of high strength steel wires are studied. It is an extension of the basic research on structural component corrosion, and it provides a more comprehensive theoretical basis for evaluating the durability of the structure.In this paper, two kinds of test methods are used to speed up the corrosion of high-strength steel wires: one is the non-external force corrosion which used electric; the other is artificial simulated natural environmental corrosion which use the prestress force. According to the two methods above, the different corrosion rates are obtained by controlling the different corrosion time of each group of specimens in electric corrosion specimens;the different corrosion rates of artificial simulated environmental corrosion specimens can also be get by controlling the different prestress force imposed on each set of specimens. The axial tension tests of high strength steel wires with different corrosion rates are carried out, and the change rule of its material properties and mechanical properties are studied after corrosion. Through the tests, the force-displacement curves and the failure forms of high strength steel wires can be get.Compared them with the test results, the influence of the corrosion on the mechanical properties of high strength steel wires is finally obtained. Specific research contents are as follows:The first chapter: through the introduction of the corrosion situation of ordinary steel bars,the destructive damage of corroded high strength steel wires to structures can be get.The focus on the application status of the high strength steel wires in bridges,its corrosion types and influence factors are introduced, and the case analysis of the high strength steel wires ’ corrosion situation are carried out.The second chapter:based on the corrosion mechanism of ordinary steel bars in concrete structures, different methods to speed up the corrosion of high-strength steel wires are put forward,and the design of the test and the method to make the specimens are introduced in detail.At last,the processing method of the corroded specimens are introduced.The third chapter: by comparing the existing corrosion rate test methods of highstrength steel wires, a new method which called section corrosion rate test method is presented. The corrosion rate after the test and analysis for corroded specimens by using the average corrosion rate test method and section corrosion rate test method can be get. The specific operation procedures,the principle of the test and test instruments for the proposed test plan are introduced in detail.The fourth chapter: after tensile test of the corroded high strength steel wires, the stress- strain relationship curve can be obtained. The change between elastic modulus of high strength steel wires of different corrosion rates, the main factors that result in the change of elastic modulus and the damage characteristics of the cross section were analysed.The fifth chapter:By modeling analysis with ANSYS software for part of the specimen test and possible corrosion situation in engineering structures, the influence on mechanics performance of different high strength steel wire corrosion types were analysed.