| In cable supported bridges, cables are important load-bearing and load transmission member. Owing to the role of the load and the environment, and some problems in the design and construction process, the cable will always have a variety of different diseases, which affects the operational safety of the bridge seriously. Therefore, research on the corrosion law and performance of the steel wire of the corroded cable has been carried on, so far, it is still a hot research topic. This paper relies on a major research project of Jiangsu Provincial Department of transportation——Research on key technology of long span cable supported bridge maintenance, this paper made a systematic analysis on the corrosion law and performance of corroded cable wire, and made a comprehensive study of inspection, evaluation and maintenance of cable systems. The main contents are summarized as follows:(1) Discussed the various diseases of the cable system and analyzed the causes of these diseases. Based on these diseases and the structure of cable system, proposed the concept of the damage state and the service condition of cable system. Damage state of the cable is generalized to the damage type and degree of the cable; Service condition refers to other factors that affect the technical status of the cable, including protection structure, service time, environment category, stress level and vehicle flow rate, etc. According to these two conditions, a system of cable evaluation index system can be put forward.(2) Analyzed the corrosion mechanism and influencing factors of cable steel wires, and studied the mechanical properties of corroded steel wires, including the tensile strength, elongation, elastic modulus and fatigue corrosion of steel wire. Research of the corrosion mechanism of the cable wire and the mechanical properties of the corroded steel wire provides a theoretical basis for the technical condition assessment of the cable. (3) According to the structural characteristics and these two conditions of the cable, a more comprehensive evaluation index system is proposed. Also, studied the method of determining the weight of each component of the cable. On the basis of expert investigation, calculate the weight of the cable components and sub components by using improved pairwise judgment matrix.Brought forward cable technology comprehensive evaluation method. Finally, tested the assessment method with the real bridge example. Proposing this evaluation method, the evaluation index system of the current cable is perfected, the weight of each component of the cable is optimized, and the evaluation result of the cable is more close to the true state of the cable.(4) Reference to the research of preventive maintenance in foreign countries, introduced the concept of preventive maintenance of cables. Proposed the concept of preventive maintenance of cable, and realized the effective combination with traditional cable maintenance. On the basis of the evaluation of the technical condition of the cable system, this paper predicted that the preventive maintenance time of the cable is determined.and the corresponding preventive maintenance measures are put forward for the various types of early diseases. Putting forward the concept of cable preventive maintenance, makes it possible to find the disease of the cable and take effective measures to delay the development and reduce the maintenance cost of the cable. |
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