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.
In order to accommodate the expanded busway and the increased vehicle mass from the electric vehicles, 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 local weaknesses at the halving joints at mid-span.
The bridge structure presented numerous constraints including a dense array of utility services housed within the bridge, the presence of previous bridge modifications, maintaining traffic on the structure for the duration of the works and an aesthetic requirement to maintain is current elegant appearance within its prominent inner-city location. A unique strengthening design was developed which recognised these constraints while ensuring constructable detailing of the works.
The strengthening design developed incorporates flexural strengthening using external post-tensioning directly fixed to the webs of the bridge using an ultra-high-performance fibre-reinforced concrete (UHPFCR) blister. Shear strengthening of box-girder webs using prestressed hot-rolled bars was also designed along with a carbon fibre reinforced polymer (CFRP) strengthening solution at the half joints. The works also utilise near surface mounted (NSM) stainless steel reinforcement to provide additional strength where thickening of sections is not possible.
This presentation shall provides an initial 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 in order to ensure effectiveness while minimising the risk of damage during installation.
