Sydney Harbour Bridge Preservation Benefits from 3D Mapping
Cutting-edge 3D mapping technology has emerged as a new secret weapon in preserving Australia’s most famous man-made icon. Reaching up 134 metres from sea level, and measuring 48.4 metres across and 1,149 metres in length, the Sydney Harbour Bridge is the world’s tallest, widest and fifth longest steel span bridge. With the relentless battering it receives from gale-force winds, corrosive saltwater and the 160,000 cars that cross each day, ‘The Coathanger’ presents unique maintenance challenges for the NSW Roads and Maritime Services (RMS) agency.
To manage the perpetual attention the bridge requires to keep it in top condition, RMS partnered with Geographic Information System (GIS) technology specialists Esri Australia to create a maintenance system built around highly-detailed, interactive 3D maps. RMS GIS Application Developer John McGlynn said engineers and maintenance crews ‘fly through’ the digital maps on their PCs and laptops to examine each of the bridge’s thousands of different structural components.
“This up-to-date, scalable 3D view of the bridge enables our personnel to fly in, out and around the bridge without leaving their offices,” Mr McGlynn said. “Each bridge component is colour-coded based on its condition and the different condition levels can be ‘switched’ on or off to isolate them for the viewer. For example, everything except the urgent maintenance jobs can be hidden. We can also click on a piece of the bridge and bring up a picture of it with individualised maintenance information – including the material it’s made of, the type of maintenance to be conducted, and the cost involved. In this way, our maintenance officers can visualise which components need attention, determine the cost of carrying out the work and then set up a maintenance schedule.”
The 3D model itself is detailed enough that users can ‘fly’ back until the bridge is just a pinpoint, or zoom close enough to see the individual hand rails on the cords that secure the span.
Esri Australia NSW Business Manager David Purkiss said the system was a prime example of how GIS technology was modernising traditional infrastructure management.
“In some cases in Australia maintenance schedules and bridge condition records are still being kept on paper – a system that makes it incredibly difficult to organise, store and retrieve information,” Mr Purkiss said. “GIS technology is light years ahead of this type of archaic maintenance system and RMS is certainly at the forefront of modern infrastructure management technology. And while they use the technology to service the Sydney Harbour Bridge, it could be the Eiffel Tower or the Snowy Mountains dams. The same 3D GIS technology can be tailored to manage the maintenance of any man-made structure.”
Mr McGlynn said the technology also accounted easily for the constantly changing nature of maintenance tasks. “GIS technology allows inspectors to take laptops on to the bridge itself and update its condition live into our system. This ensures the condition of the bridge is constantly being kept up to date. In fact, the technology has been so useful, a 3D model has also been built of the nearby ANZAC Bridge with plans to adopt the same system for its maintenance.”