Assessment Of Remaining Corrosion Fatigue Life For Existing Steel Bridges

Corrosion and fatigue are the two main factors for remaining fatigue life and service safety assessment of existing steel bridges. However, in the existing research, corrosion and fatigue were considered respectively for evaluation of remaining fatigue life and service safety of existing steel bridges, but the corrosion fatigue is an important problem in the real engineering structures, therefore the research for assessment of remaining corrosion fatigue life for existing steel bridges is necessary. Based on the literatures of the evaluation for corrosion fatigue in structures and the research results for assessment of remaining fatigue life, the evaluation of fatigue life in corrosion environment is studied, then a method for evaluation of corrosion fatigue of steel bridges is established. In details, the following aspects are investigated:1. Based on summarizing the research of fatigue remaining fatigue life and service safety of existing steel bridges and comparing the differences between steel bridges and other domain in research progress, a method for evaluation of steel bridges remaining life in corrosion fatigue condition is proposed.2. Because of lack of stress intensity factor formula in complex structures, the method for calculating stress intensity factor by finite element method is necessary. By the finite element method, the stress intensity factors for semi-ellipse surface crack and quarter-ellipse corner crack are computed.3. The changes of fatigue strength of riveted category in corroded components are studied by fatigue tests on the specimens cutting from the web components of the existing riveted steel plate girder.4. The method for assessing corrosion fatigue life is applied to an existing steel bridge, the effect of corrosion on fatigue crack is studied, and the corrosion fatigue life is evaluated based on fracture mechanics.