Bridges

The Victoria Bridge has been a key crossing of the Brisbane River for public transport, private vehicles and pedestrians/cyclists since its opening in 1969. As part of the Brisbane Metro project, the structure was closed to general traffic in January 2021 to prioritise public and active transport by increasing the busway corridor and adding a dedicated cycleway to the bridge.

To accommodate an expanded busway, new vehicle barriers were added on the bridge deck along with improvements to the existing drainage system to accommodate the new lane configuration. Provisions were also made for the installation of a future shade structure along the downstream side of the bridge to improve pedestrian amenity over the busy river crossing.

Due to the increased vehicle mass from the new fleet of electric metro vehicles as well the associated additional mass from the above deck works, the 50-year-old post-tensioned precast box-girder bridge was assessed for strength and was found to have flexural and shear deficiencies in isolated locations on the approach spans as well as minor weaknesses at the halving joints at mid-span.

Strengthening works were required to be carried out recognising the many constraints imposed by the existing structure including a dense array of utility services housed within the bridge, the presence of previous structural modifications, maintaining full busway operation on the structure for the duration of the works and a requirement to maintain the current elegant aesthetic appearance of the bridge. A unique strengthening design was developed which recognised these constraints while ensuring appropriate and constructable detailing of the works.

This paper provides an overview of the bridge refurbishment along with the key areas of the strengthening works. It also describes how the design and detailing was carefully planned to ensure effectiveness while minimising the risk of damage during installation.