Prediction Of The Remaining Life Of Damaged Cables And Research On Method Of Safety Assessment

The cable-stayed bridge, also known as the skew bridge, its development experienced a long from rough to the fine process. Because of its lightweight structure, strong across ability and more convenient construction, Pier less, so the probability of a vessel collision is small, navigable width make it has a navigation capability. Also the lateral stiffness of structure is strong enough to resist the wind and it has a handsome appearance, etc. Cable in the cable-stayed bridges is the main load-bearing power transmission components, the relatively small size make it can most easily damage in the cable stayed bridge structure system, and a relatively high degree of sensitivity to the disease. According to the statistics, the recent cable-stayed bridge disease appears mostly in cable. The mechanical properties of the stay cables were decreased, the corrosion accelerated and the durability decreased. So the research on the damage stay cable is of great significance for the development and safety operation of cable-stayed bridge.The corrosion mechanism of the cable is researched in the paper to find out how the external environment can have an impact on the corrosion rate of the cable and which factors may have bigger influence on corrosion rate in the environment.The electrochemical test program based on electrochemical principles and orthogonal design principles is developed to research the influences of outside temperature,content of NaCl,PH value and the interaction of the two factors on the corrosion of high strength steel wires. Then the function of the high strength steel corrosion rate and external environment corrosion factors is analyzed.To study the corrosion of the cable, a diffusion model is established. And diffusion mechanism of the external environment corrosion factor along the cable jacket damage to the interior is analyzed when when the cable jacket are damaged. According to Fick law and the actual situation, mathematical equation is set up. Then we get the answer of that equation through presume boundary and initial conditions, thus concluding the relation between the concentration of corrosion factors with time and location.After obtaining the corrosion factor concentration of inside of the high-strength steel cable, etching amount of high tensile steel wires and cables can be get according to the function relationship of different concentration of corrosion factor and steel wire corrosion rateAfter a series of theoretical derivation, we finally get the cable corrosion amount and lasso mechanical performance degradation degree is deduced. And the bearing capacity of the lasso is evaluated again.On the basis of this, we put forward three lasso safety assessment criterion:carrying capacity decision basis、corrosion quantity decision basis and Broken wires rate decision basis. According to the specification, we divided the lasso into five grades to evaluate the safety of the cable. According to the safety of the corrosion process lasso and lasso judgement basis, the specific processes and methods to predict the life of the lasso are put up with, thus providing a theoretical basis to determine the cable replacement time...