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WATCH: HDD connects coastal island

Redland Bay Islands are enjoying better telecommunications and internet connectivity than ever with NBN thanks to the work of horizontal directional drilling (HDD).

Although only 2 km from the Brisbane mainland, Redland Bay Islands’ permanent residents who are reliant on certain utilities have struggled with limited and unreliable communications and connectivity.

In early 2020, five of the Redland Bay Islands communities received a stronger connection through its own NBN rollout – awarded to telecommunication and ICT network provider Visionstream.

The NBN Bay Islands project promised major gains to the communities, but also presented complex challenges.

Visionstream Senior Project Manager Queensland (NBN) Andrew Desmarchelier said it was one of the more complex builds his team has undertaken, though the challenge of designing a process to meet the requirements of all stakeholders was enjoyable.

“Whenever we undertake a project like this, there is a lot of different factors to manage and at all times our focus is providing exceptional technical and service delivery for our client,” said Mr Desmarchelier.

The most significant challenge was the area’s unspoiled and protected environment, which meant the traditional method of marine trenching to complete island connections was not suitable.

After identifying the best solution to balance the project’s priorities, Visionstream partnered with HDD contractors Pipeline Drillers Group and trenchless designers Future-Proof Solutions to design and construct the connections using HDD.

Redland Bay Islands’ required HDD as traditional connection methods were not suitable.

The final design comprised four 140 mm HDPE crossings to the five islands at lengths of 1000 m, 820 m, 550 m and 350 m.

Future-Proof Solutions General Manager Col Harris said some major engineering and construction constraints needed to be factored into the design.

“As well as the obvious obstacle of the island geography, the project’s difficulty factor was magnified by the sand and rock geology, limited entry and exit points and the logistical challenges of needing to use barges instead of land transport,” said Mr Harris.

“But, by investing in detailed and responsible design, including constructability studies and hydrofracture analysis, we were able to create a solution which fully complied with the strict project requirements and effectively mitigated the risks.”

Pipeline Drillers Group Director John Whitbread added the project demonstrated how HDD is a competitive option in island connections.

“There’s a misconception out there that long HDD bores under marine environments are too expensive, but cost comparisons in this project showed that wasn’t the case,” he said.

“And to drill a pipeline in over a distance of a kilometre, causing no marine or surface disruption along the span, really sums up the win-win in terms of cost and benefit that HDD brings to NBN and other island connection projects.”

For more information visit the Future Proof Solutions website.

If you have news you would like featured in Trenchless Australasia contact Assistant Editor Sophie Venz at svenz@gs-press.com.au

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