Concrete Pole line of 108km rail spur

New high capacity electric trains will be able to operate along Queensland’s 108km Bauhinia rail spur – from Rangal, south to the Rolleston mine – before the end of this year, thanks to the investment in a new concrete pole transmission line by Aurizon.

The Aurizon project was specified in Rocla Duraspun® concrete poles and is a 132kV transmission power line and substation featuring a total of 49 poles ranging from 20m 80kN to 34.5m 80kN and manufactured at Rocla’s Rockhampton- based facility.

Gavin Roberts is the Site Engineer for Laing O’Rourke, the contractors responsible for construction of the line. He said, “the project had come together incredibly well thanks to collaboration with Rocla at the outset to address concerns about pole leveling and orientation.”

“The vast majority of transmission poles were specially designed for extra height and strength due to the site being a flood risk zone. This meant the poles needed to be installed in three separate sections, and required the pole bases to be perfectly level and orientated to prevent any pole lean or twist,” he said. “This was a challenge given the bored holes were six metres deep, meaning the pole base only stands one metre out of the ground.” Rocla suggested the use of a digital level with temporary stays around the perimeter of the base hooked up to chain blocks. “It worked out perfectly and it was a big relief when we finished erecting the first pole which stood perfectly plum,” said Gavin.

With the orientation also needing to be accurate, Rocla provided a zero point on the pole bases allowing the surveyors to mark out either side of the pole to line up the orientation points. “With all the poles pre-drilled it’s pretty essential to get the orientation right so that when we run the wire the cross arms are spot on,” said Gavin.

Rocla Sales Representative Samuel George said the project was a great example of collaboration with a meeting held between Laing O’Rourke and Rocla prior to the supply of poles and the attendance of experienced Rocla staff on the ground for the first delivery and installation. “Consistent communication between the Rockhampton factory and the Laing O’Rourke site manager has ensured this project has been delivered successfully to specifications,” he said.

When standing the sectional poles, rather than using a crane to hold the pole while being backfilled and while the fill dried overnight, Laing O’Rourke created supports using the temporary stays around the perimeter, the chain blocks and long slings instead, freeing up the crane for other duties. “We used this system to both help orientate the poles and to leave there as support while the backfill would dry,” said Gavin.