The Bridgewater Bridge is a 1,273m long precast segmental viaduct in Tasmania, just north of Hobart. The new bridge replaces the aging Bridgewater causeway and bridge crossing. The 3.4m deep match cast segmental dual concrete boxes are constructed in the balanced cantilever technique then stitched together to create a single sweeping curve deck. The superstructure is made up of a total of 1082 segments, all with differing geometry and reinforcement requirements.
What did we do?
Hoffcon were engaged by McConnell Dowell | VSL to provide the 3D reinforcement shop drawings for the match cast precast segmental project. Given the high level of variability between all segments, the Hoffcon scope was based around development of constructable, prefabricated bar arrangements that were able to be assembled with confidence for each segment type. Sounds complicated….. it was, but that’s what we love.
Shop modelling was conducted in Revit with Hoffcon producing 3D models to the client along with traditional 2D drawing sheets, reinforcing schedules and information. This for the reinforcement production, cage assembly and installation into the short line segment moulds.
Our awesome team
On this job we had Dean Reid as Lead Digital Engineer, who was supported by our digital engineering team of Kaitlin Pickett and Hawaiki Wallace. These guys were at the coal face, adjusting and refining cage layouts to achieve construction efficiencies.
Technical and construction support was provided by Anton Kivell and David Hoffman, who assisted in the development of solutions in highly congested areas bringing their design and construction expertise together.
Hoffcon leveraged the internal range in experience from multiple team members both in digital modelling, systems and software.
What was needed?
The mission for Hoffcon was to produce a reinforcing cage layout for each segment type that could be ordered, assembled, and positioned into the mould removed of clashes with minimal disruption, therefore mitigating programme disruption.
This was made challenging by the density of reinforcement required in some locations (common in segmental construction) and the interaction of many interchangeable elements. This required the detailed interpretation of the design drawings, along with the development of alternative reinforcement arrangements. This had to meet the design intent while also achieving the constructors’ requirements in order to create a buildable reinforcing cage. This all had to be done to Australian standard and code requirements; cut and bend process; and fixing process of the reinforcement.
