Fatigue Properties Study Of Xinghai Cross-sea Bridge Anchor Box

The paper study the fatigue properties of the anchor box connecting boom and main truss, Xinghai bay bridge engineering for the project. After2million times cycle loading, the tress state of anchor box is stable, structural fatigue performance to meet the design requirements. Using the finite element software analysis the fatigue properties. VonMises equivalent stress used as the equal stress that multi-axial stress transformed into a simple uniaxial stress, Stress ratio using R=-1, simulate the state of tension and compression. Mean stress correction theory using Gerber, be able to better simulate the fatigue properties of ductile materials. Testing Stress is less than the theoretical value, And during the experiment, the stress of anchor box is small, the structure is under linear deformation stage, Structural system design is safe and reliable. Due to the fatigue properties of the weld is affected by construction technology, Adapt Sr-N curve to consider construction technology for processing; Results show that this method can be well to consider the impact of the production process. Preliminary export to analysis anchor box amplitude fatigue theory under a typical history load.The rain flow counting method used to count fatigue stress cycles, Palmgren-Miner linear damage theory was adopt to calculate fatigue damage. Using biaxiality indication to qualitatively judge the stress state of member in any history load. When coefficient values is zero, indicate that the structure is under uniaxial stress state, when it is negative one for the pure shear state, when it is one, indicate that the structure is under pure biaxial state; Analysis results showed anchor box welds stress state a gradual transition from the pure shear to uniaxial stress state from the weld to internal. By the state of the overall force structure qualitatively, can guide the design focus in future and well provide a reference for future anchor box designed.