Utility pipe replacement wins accolade

Posted 22 September 2016

Water pipe replacementThe challenge of replacing a 150-year-old water main under one of Melbourne's busiest streets has  earned South East Water (SEW) and its construction contractor, Interflow, a major accolade.

The St Kilda Road Main Renewal Project was recently awarded the Victorian Civil Contractors 'Earth' Award for projects between $1 million and $5 million.

“When this water main was originally laid, it was the days of horses and carts,” said South East Water's General Manager Asset Creation Charlie Littlefair.

“Melbourne’s population is now around 24 times larger than it was back then – it’s why we needed to upsize the main pipe from 250mm to 300mm to cater for even more future development and population growth.”

The 1.4km of cast iron mains that needed to be replaced laid under a tramway, four lanes of southbound traffic, a bicycle lane and a long line of iconic elm trees.

The location and condition of the mains meant the renewal project could not be completed using newer replacement techniques such as pipe cracking. The only solution was excavation, removal and replacement with a bigger polyethylene pipe.

The project was further complicated by nine months of community and stakeholder management, which was needed before and during construction, Littlefair said.

“To minimise interruption – especially to the hundreds of thousands of commuters who use St Kilda Road every day – the outcome of consultation with VicRoads was to undertake the work at night between 8pm and 6am,” he said.

“To further reduce the impact of our work, which occurred on the road’s bike lane, we divided the project into sections of 200m. Each night a section was replaced, welded and sealed so by the next morning, traffic was unaffected.”

The noisiest works were scheduled prior to 11pm each night and disruption was further minimised by muffling the reverse beeping on machinery, and lining bins with rubber to reduce the sound when old cast iron piping was dropped in.

An additional complication was that separate works, led by Melbourne Water, were being undertaken on a nearby water main.

The Alfred Hospital was reliant on supply from both mains so collaboration was required to ensure one of Melbourne’s largest healthcare institutions was never without water.

Littlefair said the project's success bode well for future upgrades to be completed as part of SEW’s Mains Renewal Program.

“The original cast iron main replaced in this project was one of Melbourne’s oldest operational water mains – it’s been a conduit to supply fresh water into Melbourne’s inner south eastern suburbs for more than a century,” Littlefair said.

“It would have been the first asset laid in the ground in that location and now it’s joined by an amazing underground network of assets from telecommunications to other utilities.

“It means that the complexity of our renewal projects will only increase over time, both in construction, and community and stakeholder management. We’re ready for the challenge as this project proved – ensuring that people can go about their business while we seamlessly improve the reliability of our service.”

It is now anticipated the St Kilda Rd water main will not need to be touched for more than a century.