Graco sprayers and hydraulic proportioners from Australian Urethane Systems were used to carry out essential waterproofing and resurfacing work on the Sydney Harbour Bridge.

Listed in the Guinness Book of Records as the world’s widest long-span bridge, Sydney Harbour Bridge has a total length of 1149 metres with more than 160,000 vehicles crossing it each day.

After 80 years, the Sydney Harbour Bridge required essential waterproofing and resurfacing work, which involved stripping the original concrete deck. Key objectives of the resurfacing and waterproofing work included creating a smoother, more durable road surface, decreasing road noise, reducing risk of corrosion and structural damage on the bridge deck, and rejuvenating the bridge while also minimising the need for future repairs.

Three Graco XP70 Plural component sprayers and four Graco Reactor H-XP3 hydraulic proportioners were employed for adhesive and polyurethane spraying. Everything including the material, generators, compressors and Graco equipment was set up on trucks that travelled down one lane while spraying the adjacent lane.

A three-layer polyurethane waterproofing system was applied to the concrete deck of the north and south approach spans with the first primer layer applied using a power roller, followed by the polyurethane waterproofing layer and the final primer layer applied by manual spraying.

Heated crumbed rubber bitumen was sprayed onto the concrete deck of the arch span to provide a waterproofing seal. Aggregate was then spread over and rolled into the spray seal, following which the asphalt was applied.

The essential bridge maintenance work was completed over two weekends in January 2012, with the entire waterproofing and resurfacing completed 10 hours ahead of schedule.