Civil engineering cables are subject to two main causes of damage : fretting-fatigueand corrosion. These causes can be activated on the same location of the cable and interact between them, conducting to early wire breaks in the cable. An experimental device of fretting-fatigue reproduces, at the wire scale, the stress conditions of stay cables or suspension cables. A fretting-fatigue study in a corrosive environment was carried out. It consisted in studying the damage of wires subjected to fretting-fatigue in a solution of sodium chloride. In this case, lifespans are slightly changed. Then, two stages were separated : a stage for initiating cracks and a stage for propagation. In the test conditions, fretting is predominant during the initiation stage of cracks. Therefore, it was chosen to initiate a crack by fretting-fatigue and then to propagate it byfatigue-corrosion. Some solutions were tested and the propagation in an ammonium thiocyanate solution shows a major reduction of the specimen lifespan. This study will go on with the use of electrochemical techniques in order to accelerate corrosion phenomena.
Etude de l'influence des conditions environnementales sur le comportement en fretting, fatigue et fretting-fatigue des câbles du génie civil