West Gate Bridge: Management of Fatigue Cracking
- Publication no: ABC-CAS104-14
- Published: 22 October 2014
Melbournes 2.5 km long West Gate Bridge includes an 848 m long steel box girder portion, over the Yarra River, comprising cable-stayed spans and an orthotropic steel deck. As with other similar bridges throughout the world, the steel spans of the bridge have, in recent years, been experiencing an increasing incidence of fatigue cracking. VicRoads has been engaged in the implementation of a major program of fatigue crack treatment works, though management of fatigue cracking has been a feature of the bridge maintenance task from early in its service life. With increases in traffic volume in recent years, the inspections to detect and monitor cracks and the treatment of fatigue-prone details has become a major component of the bridge maintenance task. The majority of the cracking is within or adjacent to the orthotropic deck plate and the result of stress concentrations in welded connections, due to local loads on the deck. This paper provides a summary of the typical fatigue cracks and the range of treatment details that has been developed. Finite element analysis has assisted in comparing options for fatigue repairs and assessing the improvement the repairs provide.