360° Surveying was contracted to undertake high-precision surveying for the structural steel wall and roof modules of Building 22 at the Osborne South Australian Naval Infrastructure (ANI) Project. Building 22 measures 187 m long, 87.4 m wide and stands at 50 m high. This building is the largest single span 'shed' in the Southern Hemisphere and only the second building in the world to have been constructed with rotating walls.
360° Surveying was required to monitor the structural movement and accurate placement of the modules during wall rotation and roof lifts. Our first responsibility was to position the rotation pins on top of the concrete walls to a tolerance of ±1 mm. On the rotation and lift days 360° Surveying was responsible for monitoring the modules using high-precision surveying for twist and flex to maintain engineering tolerances. Due to the size and shear weight, the wall modules were modelled to flex by 80 mm during the rotation.
A number of challenges were overcome including developing a method to convert target coordinates into offsets from the engineers datum point in a 3-dimensional arc, creating a process to share the data with the engineers in real-time, becoming the only control mechanism for the first wall rotation due to equipment malfunction and target placement 50 m up in the air.