Affiliations: Consulting Engineers Haug og Blom-Bakke AS, Oslo, Norway | The Norwegian University of Science and Technology (NTNU), Trondheim, Norway | SINTEF, Trondheim, Norway | Det Norske Veritas, Oslo, Norway | Norwegian Public Roads Administration, Oslo, Norway
Abstract: Wire fractures in the main cables of the Lysefjord Suspension Bridge display an approximate linear relationship with time. Uncertainties related to wire fractures in sub-layers, reduction of load-carrying capacity and lifetime, and future development of wire fractures have prompted extensive investigations of the main cables. Failure analyses of fractured Z-wire samples and fracture mechanics analysis concluded that cracks have initiated and propagated from surface imperfections. The potential for hydrogen atom generation and absorption that causes hydrogen-induced cracking is discussed. Hydrogen atoms result from the hot-dip galvanization process, or due to corrosion. Evaluation of remaining load-carrying capacity and the need for strengthening of the main cables are briefly discussed and methods for surveillance of wire fractures are presented.