Mt Crosby Weir Bridge Upgrade
About the project
The project involved the decommissioning and re purposing of the heritage-listed Mt Crosby Weir Road Bridge, originally constructed in 1927. Due to its structural limitations, including a maximum load capacity of 9 tonnes and inability to support two-way vehicular traffic—the bridge was no longer suitable for modern vehicle use.
Location
Mt Crosby, Queensland
Client & Duration
Seqwater
Oct 2024 - Jul 2025
Project Scope
» Separable Portion 1: Construct only of a concrete pedestrian pathway, stairs and handrails, rectification of damaged asphalt, and modifications including concrete infills, fencing and guideposts, and kerb and channel works.
» Separable Portion 2: Removal and disposal of the existing weir bridge balustrades, and the procurement, installation, testing and commissioning of new weir bridge balustrades.
Challenges
» Pensar engaged a geotechnical engineer to manage 300x300mm sink hole which was compacted with stabilised sand
» Due to the bridge’s heritage listing, no drilling into the existing substrate was permitted, and the original hold-down bolts were required to be reused for the installation of new balustrades. During installation, it became evident that the existing bolt lengths were insufficient to allow for a level installation of the balustrade panels
» Working over water and at heights led to environmental concerns. Pensar installed edge protection for safety, and barriers were used along the length of the bridge to ensure debris from asphalting did not enter and pollute the local waterways
» Pensar provided an alternative design for East Bank gate, requiring raising the gate posts and allowing for smooth passage over the bridge deck.
Achievements
» A positive relationship was formed between Pensar site crew, management, and Seqwater
» Implemented mitigation strategies including resequencing works, accelerating activities during favourable weather and working windows and increasing resources to recover lost time due to natural disasters
» Pensar successfully maintained the integrity of the heritage-listed site.