Bridges

The 313 m precast segmental box girder Victoria Bridge is a key Brisbane River crossing, which opened in 1969. The structure is a central link for public transport, pedestrians and cyclists within Brisbane and will be required to operate, carrying increased loading beyond its intended purpose.

As part of the Brisbane Metro Project, remediation of the bridge was required to reconfigure the deck to accommodate the future vehicle layout whilst undertaking local strengthening to several areas of the structure, to provide reliability for the future loading. Works included flexural strengthening using external post-tension tendons, shear strengthening using vertical prestressed bars, carbon fibre strengthening of half-joints, installation of near-surface-mounted reinforcement and post-installed reinforcement with chemical adhesives.

Construction of the works incorporated many challenges, including several thousand drilling operations as well as multiple hundred coring operations into the existing structure with its dense fields of post-tensioned tendons. Work on these activities was carried out over the Brisbane River and Riverside Expressway with further construction required within confined box girder voids containing major services and utilities. Such challenges required close collaboration between the design and construction teams throughout both the design and construction phase.

This paper presents key learnings from the works, including the non-destructive methods for identifying and avoiding tendons and reinforcement, in situ concrete pours in confined spaces within box girder voids, planning of works and use of offsite trials and access considerations over and adjacent to live traffic.

With a growing focus on sustainable management of infrastructure including the rehabilitation of bridges rather than replacement, such learnings associated are expected to be applicable to a wide range of future asset remediation projects.