The Effect Of Joint Working Mode Between Steel Wires On Local Bending Stress Of Stay-cable

In recent years,a series of researches have been done which found that the bending stress at the anchor portion is the principal factor lead to failure of the stay cables. bending stress calculated in uniform bending rigidity theory is far from the demand of engineering. In this thesis, the effect of frictional stress between steel wires has been taken into consideration during the analysis of stay-cable's bending stress concentration. And the combined action between wires have been studied detailed in both theory and experiment. Based on the Sutong Bridge, a finite element model has been built with ANSYS, the process of delamiation has been simulated, and the change of bending stress been attained also. The main objectives in this thesis are:①The research on bending behavior of stay cables have been in-depth investigated. The effection of bending stress to fatigue behavior of stay cables has been recognized by comparing the the work of each country all over the world. The concept of layered-slipping for the analysis of bending stress have been proposed after introducing the character and the bound of each theory.②I n the aspect of theory, the paper deduces formulas for calculating normal stress between steel wires in the stay-cable by way of integration and differentiation method.③In the aspect of experimental, the paper advances a new method to testing the friction coefficients according to the characters of metal mates and friction theory.④In the aspect of numerical simulation, the paper proposed mechanics analysis model to simulate the working patterns between steel wires creatively, builded the finite element model to analyse the bending stress and analogue simulate the layered-slipping condition.⑤In the aspect of engineering, based on Sutong Bridge, the paper simulated the process of sliping, and attained the change of bending stress. The differents between the solutions attained by layered-slipping model and the theory of uniform bending stiff have been discussed. Based on the results, the rotationally of the layered-slipping model and method proposed in this thesis has been proved.All the work and results in this thesis have positive effects to the further research on bending fatigue of stay cables.