The Research Of The Fatigue Reliability Of Prestressed Concrete Beams Under Corrosive Environment

In recent years, the road transport projects in China develops with each passing day, more and more cross-sea bridges are under construction or nearly operational. However, as the increased traffic volume, heavy vehicle load leads to the bridge structure or component to put too much long-term fatigue loading alternating, especially, the bridge structures in the marine environment, due to the coupling effect between the corrosion of marine environment and long-term fatigue loading, exist serious safety hazard, therefore, the study of the fatigue reliability for the bridge structure in corrosive environment to ensure the safe operation of the bridge is a major issue need to be solved.In this paper, the fatigue reliability of priestesses'concrete beams under the corrosion testing was studied. Firstly, it described the basic concepts of the structural reliability theory and corrosion fatigue, through the theoretical analysis of fatigue reliability obtained the for-mule of fatigue reliability indexβfor priestesses concrete beams. Secondly, the analysis of the beams variation of the fatigue reliability indexβand the factors and the prediction method for the corrosion fatigue life. The main contents are as follows:(1) Introduces the basic concepts of structural reliability theory and principles, calculation methods of the reliability index and the basic concepts of corrosion fatigue.(2) Analyzes on the fatigue properties of the PC steel strand and the general steel and also the fatigue properties of bonding between the two parts under the corrosion environment for priestesses concrete members(3) According to corrosion fatigue reliability theory, analyzes and calculates the corrosion fatigue reliability index of priestesses concrete structures under different levels of corrosion rate and different load stress, and analyzes its variation with the corrosion rate of the strand and variation of stress amplitude, obtains the fitting equation of the curve.(4) Describes the calculation and prediction method of corrosion fatigue life for the general components, and analyzes the factors of the corrosion fatigue life for priestesses concrete beams, and studies its variation with the components corrosion rate and different loading stress amplitude and stress ratio.