West Gate Bridge: refurbishment of Demag expansion joint and roller bearings

Melbourne’s West Gate Bridge, first opened to traffic in 1978, is around 2.5 km long and comprises an 848 m long five-span steel box girder portion over the Yarra River and two continuous concrete box girder approach viaducts 871 m and 670 m long. The longitudinal expansion and contraction of the steel bridge and concrete viaducts is taken up at the two ends of the steel bridge, which are at Piers 10 and 15. At these piers, the ends of the steel bridge abut the end of the adjacent concrete approach viaduct. This paper provides a description of the expansion joint and details of its performance and the major refurbishment works being undertaken on the joint. The joint is segmented and each stage of the refurbishment work must be completed within a 12-hour night shift and with limited lane closures to avoid unacceptable interference to the road traffic.Furthermore, at both Piers 10 and 15, there are eight roller bearings under the steel bridge and the abutting concrete bridge. As well as describing the current remedial works, this paper presents a history of the problems encountered with the rollers, some of which relate to the original design and include broken gear teeth on the racks and pinions and bearing misalignment. The racks and pinions had originally been fitted to the rollers to maintain their alignment and this paper describes the program of works currently underway to replace the racks and pinions on each of the rollers.