Novel Method for Developing S-N Curves for Corrosion Fatigue Damage Assessment of Steel Structures

Abstract

Abstract: Corrosion is one of the main problems in steel structures. The combined effect of corrosion and fatigue caused by cyclic loading magnifies the damage severely reducing the fatigue life of the structure. Steel bridges in coastal and industrial zones are among the structures most vulnerable to corrosion fatigue. Up until now there have been no accurate methods introduced for assessing corrosion fatigue damage and predicting the future life of structures in a corrosive atmosphere. In the S-N approach based fatigue damage assessment method S-N curves should include corrosion effects. If usual S-N curves that do not include corrosion effects are used, they should be modified or safety factors should be applied to account for the effects of corrosion. The present paper describes a study carried out for improving one of the existing full range S-N curve models for corrosion effects. Using adjustments to the existing S-N model a new corrosion based S-N model was proposed. Experimental results showed that the proposed S-N model can be efficiently used for assessing fatigue damage of steel structures located in corrosive atmosphere. The S-N model proposed remains a simple single formula. The only parameters necessary for the new corrosion based S-N model are the ultimate tensile strength, Vickers hardness and the high cycle fatigue strength in corrosive environment.