D Siegert P Brevet Laboratoire Central des Ponts et Chaussées France

Niveau: Secondaire, Collège, Troisième
D. Siegert, P. Brevet Laboratoire Central des Ponts et Chaussées, France Fatigue of stay cables inside end fittings high frequencies of wind induced vibrations Summary A twenty year old stay cable was dismantled because it showed many ruptures at one of its terminations. The examination of the wire breakages showed evidence of fatigue. Analysis of the dynamic behaviour of the stay cable was carried out. It showed that the combination of flexural bending stresses with fretting stresses between the outside layer and wire serving lead to a stress range beyond the endurance threshold. Recorded measurements of transversal vibration displacements near the sockets show that high modes of wind induced vibrations (Karman Vortex) were involved in the fatigue occurrence. Examination of the internal state of three other cables confirms the analysis of displacement records in relation with the fatigue limit. 1. Introduction This paper deals with five years of investigations on a cable stayed bridge built on the sea-side over the river Loire in Western France. This bridge which had one of the longest suspended spans in the 1970's is mainly characterised by two towers of 130 metres in height, seventy-two stay-cables and a metallic deck that is 720 metres long. One of the locked coil cables (72 mm diameter) in service for about twenty years appeared to be severely damaged with lots of wire breakages in the external layer as shown in the figure 1.

• density


• correlations between


• density representation


• between traffic


• related power spectral


• inter-wire contacts


• power spectral


• spectral density


• stay cable


• vibration