Deterioration of fatigue strength of bolted connection plates under combined corrosion and fatigue

In this paper, the combined effect of corrosion and fatigue on the fatigue strength of steel connection plates is thoroughly investigated through a comprehensive experimental program. A model for fatigue strength degradation as a function of corrosion rate is developed. The mechanism of fatigue strength degradation is also examined to gain a insightful understanding of fatigue strength degradation under simultaneous corrosion and fatigue environments. It is found in the paper that the simultaneous corrosion and fatigue environment can lead to higher degradation in fatigue strength of connection plates than those subjected to pre-corrosion and fatigue test afterward. It is also found that the reduction in grain size of steel plates is one of main mechanisms for the degradation in fatigue strength of the connection plate. The significance of the paper lies in developing a testing methodology to create a simultaneous corrosion and fatigue environment for connections and study its effect on fatigue strength. The knowledge of degradation mechanism of fatigue strength of steel connections under simultaneous corrosion and fatigue environment contributes to corrosion science of steel structures.