Abstract
The suspension cables of the Lysefjord Bridge in Norway are an example of long term development of wire fractures. During the sixteen years of operation about 1600 wire fractures have been registered in the outer layer of the Z-wire. The accumulation of wire fractures follows so far a quite linear development. This long term development is created by atomic hydrogen diffusion causing hydrogen embrittlement (HE) and is not linked to any corrosion mechanism of the wire. The origin of the wire fractures is surface defects, typical overlap shear defects, created during the forming process of the Z-wires. A new basis for fracture toughness testing, fracture assessment and defect tolerance on suspension cables is presented, as the reduced fracture toughness from HE increases the sensitivity for fracture