Maintaining the iconic Sydney Harbour Bridge poses some unique challenges. The Roads and Maritime team decided that some of the more dangerous tasks should be done by robots instead of humans, and the idea for some innovative new technology was born. They may look like something out of a science fiction movie, but these robots are helping to drastically reduce safety risks to staff and members of the public.

Ready for blast off
Repainting the south approach of the Bridge is a mammoth task that includes removing existing lead-based paint from the steelwork and applying a new protective coating to an area of 92,000 m2 – five times the area of the Sydney Cricket Ground. 

In the past, workers had to use an 80 tonne self-contained platform to access the bridge steel work and sand-blast the old paint. “It’s heavy work in small spaces, with poor visibility and stifling hot conditions in summer,” says Peter Mann, Strategic Infrastructure Manager of Sydney Harbour Bridge.

Roads and Maritime collaborated with the University of Technology Sydney (UTS) to develop two grit-blasting robots. Peter recounts “The robot concept came from science fiction seen on TV. We had to make it a reality and not just a fantasy, but we had no idea how to build a robot. Luckily UTS does, and that cemented our collaboration.” 

The ‘smart’ robot is a lightweight robotic arm with artificial intelligence technology that can work unaided in unfamiliar environments, removing the safety
risk to workers. 

“Robots are able to perform the same task as human workers and it is the robot itself that becomes exposed to the risk in place of the human,” says Peter. “Money can replace a robot, but it can’t replace a life.” 

Inspector gadget
Then there’s the challenges posed by the 7.2 kilometres of confined spaces on the bridge that need to be inspected for paint and steel conditions. The solution was to develop an inspection robot that climbs along steel walls and through portholes while recording video footage. 

Known as CROC, the fully autonomous robot is kitted out with magnetic feet, a 3D sensor and a high-definition camera to automatically explore complex environments like the interior of the box girder arches of the bridge. “The robots can be sent into confined spaces, where there may be poisonous gases or where humans cannot physically fit,” says Peter. “And with their 3D laser scanning, they can also operate in the dark or in dusty areas with poor visibility.” 

The robot can plan its own path using maps generated from its 3D sensor while taking photos. The photos are used to help inspectors assess bridge conditions. 

The innovation recently won an Australian Engineering Innovation Excellence award, Engineers Australia Engineering Excellence award, an Asia Pacific ICT Alliance award, a NSW Safe Work award, and was highly commended in the national iAwards. 

With the Sydney Harbour Bridge Team now working on the next generation of climbing robots that will clean and repaint the bridge steel, Peter muses that “science fiction is becoming reality, and our dear old iconic bridge continues to be a world leader in adopting new technology.”