The iconic Sydney Harbour Bridge is famous the world over. The steel through-arch bridge is the fifth longest spanning arch-bridge in the world, and it is the tallest steel arch bridge, measuring 134 metres (440 ft) from top to water level. Like most steel bridges, the Sydney Harbour Bridge requires constant inspections and other maintenance work to keep it safe for the public, and to protect from corrosion.
The most noticeable maintenance work on the bridge involves painting. The steelwork of the bridge that needs to be painted is a combined 485,000 square metres (120 acres), the equivalent of sixty football fields. Each coat on the bridge requires some 30,000 litres (6,600 imp gal) of paint. Removal of the old paint and rust is achieved by abrasive grit-blasting, with self-contained platforms constructed around the maintenance areas.
Two autonomous grit-blasting robots now form part of the Sydney Harbour Bridge maintenance team, helping to improve the safety, efficiency and quality of the grit-blasting process.
The operator simply has to position the robot in the general area that needs to be blasted (exact positioning is not required because the robot is clever enough to work out where it is), the robot scans the structure and builds it’s own 3D map of the bridge, then once the operator is happy that the area is safe to blast he sets the emergency stop button and presses the ‘start blasting’ button on the Operator Control Unit, then the robot gets on with the blasting.
Because robots can move in ways that humans cannot, we can achieve a consistency of blast that even the most experienced blasters could not match. This image is of one of the sections on the Sydney Harbour Bridge blasted by the robot – the consistent blast lines demonstrate the accuracy and consistency of the robotic grit-blaster. And check out the close up image of the blast quality!
A quick look at the SABRE robot’s in action on the Sydney Harbour Bridge
When the SABRE Autonomous Bridge Blasting Robot was put to task on the Sydney Harbour Bridge, the world’s media reported. Here is a quick edit of what they had to say.
You can read an indepth article ‘Maintaining and old icon with new technology’ in the August 2015 edition of the Journal of Protective Coatings and Linings