The Exploring Research On Durability Of Stayecable

ABSTRACT:In recent decades, the cable-stayed bridge, with many particular advantages such as economic, reasonable structure style and attractive appearance, has become a dominant bridge style among long span bridges. However, many cables of cable-stayed bridges should be replaced in several years after construction. It not only costs much fee to replace the cables, but also results in the traffic control to reduce traffic jam or even traffic block during the replacement work. These serious results may influence the service level of bridge, cause big economic loss, and even produce a bad influence in society in the operation process of bridge structure, so more attention should be paid on the durability of cable. Taking the Quanzhou Bay Bridge as an analysis example in this thesis, broad exploration and research on the durability of cable-stayed bridge are taken. The main contents include:Firstly, the development history of concrete cable-stayed bridge in the last decades is reviewed. Then, to solve the problem of cable failure, the manufacture course of cable is researched, and the significance to analyze the durability of cable-stayed bridge is addressed.Secondly, the level of prevention system for cable and main reasons result in cable damage are analyzed, and the corrosion mechanism of cable is introduced. Combining with the area division of atmospheric corrosion in China, protection methods for cable and some current problems are researched. By the analysis of nonlinear vibration form which may induce the cable fatigue, the damage mechanism and characteristic of cable are proposed. To solve the problems of vibration and fatigue of cable, the research on measurements to reduce the vibration is taken, and the suitable device is selected.Then, relying on a cable-stayed bridge constructed in coast area, finite element model of the bridge is established, and static and dynamic calculation are taken respectively. To this bridge, main research is focused on the anti-fatigue properties of cables, parametric vibrations and finding out the cables with bad durability. In addition, change regulations of girder alignments and cable tensions are researched when cables damage in different locations at different levels. Obtaining the influence of the damages of different cables to whole structure is benefit to protect and monitor the key cables of bridge.Finally, to solve the problem of frequent replacement of cable, the characteristic and advantages of FRP, CFRP and other multiple materials are researched. Searching for new material to replace current steel is the best solution to enhance the durability of cable and extend the structural life.