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How you can benefit from trenchless technology
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Trenchless techniques for installing new infrastructure and rehabilitating existing underground assets provide many benefits to councils, water authorities and communities. It is vital for workers within the water industry to be across trenchless methods and technologies in order to provide safer worksites for contractors, minimise social costs to communities, and to reduce costs involved in capital works programs, writes Tori McLennon, Assistant Editor of Trenchless Australasia.

Trenchless technology refers to network monitoring equipment and techniques used to install, repair or replace water infrastructure while minimising surface disruption. These techniques eliminate the need for open-cut excavation and therefore offer environmental, social and economic benefits to government and the community.

In addition to these immediate benefits, trenchless technology often results in reduced costs. In a paper titled Cost and Risk Evaluation for Horizontal Directional Drilling versus Open Cut in an Urban Environment, N Woodroffe and S Ariaratnam compared the costs of open-cut excavation with trenchless methods, concluding a trenchless approach often reduces overall construction costs in an urban environment. Additionally, trenchless technologies have been developed to reduce interruption to supply during rehabilitation works, thereby eliminating the costs associated with resident notification.

Trenchless is often favoured in the water industry for its ability to reduce network water loss through novel asset management technologies. Available technologies aid asset managers to obtain the best possible data on the state of pipes, allowing for renewal of assets before failures and bursts.

Trenchless technology is used in a range of government-funded infrastructure projects, from the construction of tunnels and the installation of pipelines to the rehabilitation of existing assets, such as water and wastewater sewers.

Trenchless technology is the solution to many of the problems that Australia is currently facing; a tightening global credit market and economic slowdown means that every dollar counts. Trenchless technology is no longer an expensive alternative, but instead offers many ways to do more with less.

A number of recent projects across the country have highlighted the benefi ts trenchless technology can offer councils, utilities and their communities.

Spiral wound success in Albury

Kembla Watertech’s DiaFit pipelining team recently completed Albury’s most complex sewer rehabilitation project, valued at nearly $2 million, for Albury City Council.

 

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DiaFit lining, undertaken by Kembla Watertech for Albury City Council.

 

This major project began in February 2012 with the objective to rehabilitate two major sewer trunk mains, one beginning in the suburbs leading to the north of the city and one starting from east of the Hume Freeway and heading to a pumping station in the centre of the city.

Andrew Craig, Albury City Council Contracts Co-ordinator, said, “The smaller diameter main, first constructed around 100 years old ago, was suffering from gas degradation ranging from severe surface wear to complete loss of structural integrity. The larger diameter main is approximately 40 years old and had suffered from gas degradation ranging from surface wear to loss of structural integrity on two northern sections.”

Kembla Watertech’s extensive product offering allows the flexibility to offer the most appropriate lining methodology to suit the diameter, flow rates, time constraints, and geographic location of the pipeline requiring rehabilitation. In this instance, an expanding spiral liner using Kembla’s SWP DiaFit lining system was deemed the most appropriate solution.

Kembla Watertech’s DiaFit Project Manager, Damian Barnett, said, “In total we rehabilitated nearly five kilometres of sewer in Albury, including sections underneath the Hume Freeway and the Sydney to Melbourne railway line.”

Diameters relined as part of this project ranged from 300 to 600mm, with the longest section being 180m of 600mm diameter pipe. A number of different spiral lining profiles were used to meet all design requirements.

Two major hurdles for the team were the traffic and the weather. A joint strategy between Kembla Watertech and Albury City Council was put into place to overcome these issues. Most of the project work was conducted at night to alleviate traffic disruptions, given that over four kilometres of the sewer mains were located in the middle of the main road in Albury’s CBD.

Albury also recorded some of the heaviest winter rainfall ever experienced in the city while the works were being carried out. One of the benefits of the DiaFit system is that it does not normally require bypass pumping during installation. This minimises lost productive days due to wet weather and heavy infiltration.

Kembla Watertech’s DiaFit lining method allows sewer flow to be monitored via a plug and release method during installation, and neither the equipment nor the liner needs to be removed from the sewer at any time.

Key achievements during the project included the lining of two consecutive 300mm diameter pipes located underneath a large commercial building. Severe gas degradation left the sewer with no invert and in some places no original pipe. Albury City Council was unable to use other contractors’ methods to successfully repair the pipes due to the great risk of collapse. Council was even considering the possibility of digging and laying a new sewer line when Kembla Watertech’s experienced DiaFit team devised a method to successfully conduct a CCTV survey.

A trenchless fix for Sydney Water’s SewerFix

Insituform Pacific is currently working with Sydney Water to deliver a vital part of the SewerFix Program. The contract began in July 2009 and has two components – the first consists of planned and reactive rehabilitation of 150 to 450mm sewers, and the second comprises the inspection and rehabilitation of 225 to 900mm stormwater pipes.

The statistics for this work tell an interesting story of growth, development and innovation as Insituform fine-tuned its operations and processes to meet new challenges. In the first year of the contract, Insituform completed almost 22kms of lining and reinstated almost 1,100 lateral connections. In its second year, lining work increased to more than 31kms with over 1,400 junction repairs.

At the same time, continuous system improvements and innovation resulted in a 34 per cent decrease in the number of excavations required from year one to year two, while the amount of lining work increased by 48 per cent over the same period.

All of this was achieved while exceeding Sydney Water’s rigorous safety, environmental and community relations standards.

In the first two years of the contract, almost 220,000 person-hours were worked without a lost time injury. Over the same period, Insituform’s Community Relations Team delivered over 12,500 written notifications to residents and businesses in areas around work sites, and more than 500 individual pre-construction agreements were negotiated with affected property owners. As a result of Insituform’s attention to proactive customer relations, the number of complaints generated as a proportion of directly affected properties was 0.5 per cent, consistently well below Sydney Water’s target of less than five per cent.

Insituform Pacific General Manager, Daniel Gamboa, points to a number of factors that have contributed to the company’s successful contribution to Sydney Water’s SewerFix Program.

“One of the key factors in the success of our first Sydney Water contract has been the sense of partnership and shared values,” Gamboa said.

“Working closely with Sydney Water’s SewerFix team over this time has ensured the smooth delivery of work and has helped facilitate our growth and development. We have learned a lot from their expertise and procedural standards, and that has encouraged us to continually work to refine our operations and processes to further improve our delivery and program outcomes. As an added benefit, we have been able to share these improvements with other Australian clients.”

As this first three-year SewerFix Contract draws to an end, Insituform can proudly look back on its achievements and look forward to further growth and improvement in the Australian pipeline market.

Protecting Bendigo bush with HDD

The final stage of works is now underway for Coliban Water’s Raywood-Sebastian Pipeline, which will be utilising directional drilling to preserve protected native bushland and to navigate under a creek.

Stage 1 of the 22.4km pipeline project commenced in October 2010 and was completed in July 2011. Coliban Water commenced Stage 2 of the project in July 2012, which involves constructing 11kms of 250 ODE PE water supply pipeline to connect Raywood and Sebastian to the Bendigo supply network.

Leed Engineering and Construction were contracted to complete Stage 2 of the project, and have subcontracted the HDD portion of the works. An impressive 6.8kms of the pipeline will be constructed using horizontal directional drilling (HDD), and only 3.8kms of the pipe installation will be via trenching.

The project has four Ditch Witch rigs in operation and a fifth rig on standby. Three of the rigs are Ditch Witch JT3020 rigs, and the fourth rig is a larger JT4020 MATCH 1 drill, which has been the key to drilling through the more solid, rocky and otherwise challenging installation conditions.

Wet weather conditions impacted mostly the trenching aspect of the project, and boring was able to continue through the wet weather. Additional drilling fluid transportation trucks were required through the wetter parts of the project, due to rainwater mixing with drilling fluid and requiring more frequent trips to drilling fluid dumpsites.

It was a high priority for Coliban Water to protect native vegetation while performing the installation. The area, which once would have been covered in Australian natives, has been greatly reduced of vegetation by farming settlements, with the majority of bushland in this area remnant vegetation in road reserves.

The Rusty Head Orchid, a rare Australian native, is known to grow in prolific clusters within the boundaries of the project area, and as such was one of the contributing factors in the decision to use the environmentally sensitive installation method of HDD.

HDD was also utilised as a means to cross under a creek, which would have been costly, environmentally disruptive and impractical to trench around.

Microtunnelling under Deebing Creek

Queensland Urban Utilities (QUU) has installed a new 500m gravity trunk sewer main utilising microtunnelling technology.

QUU contracted Rob Carr Pty Ltd for both the design and construction of the Deebing Creek Project. The project involved construction of a new trunk sewer main and a new pump station, which will prepare the Deebing Creek and Ripley Valley areas for additional supply demand created by population growth.

The original client concept design included a new pump station, 11 new manholes and 14 new pipelines totalling 676m. When Rob Carr took responsibility for the project (including consultation, design, management and construction), the company amended the original designs for greater efficiency and resource use. Robb Carr’s designs provided the exact same functionality with only seven new manholes and eight new pipelines totalling 583m, including the proposed pump station. This provided significant cost savings.

The project involved construction by microtunnelling of two DN1,000 pipelines over 180m long each, and the construction of a new pump station inclusive of two cast in-situ concrete caissons for the grit collector and wet well of the pump station, at 14 and 16m deep respectively.

The microtunnelling work included installation of DN400, DN600 and DN1,000 HOBAS pipe in varying ground conditions. Rob Carr utilised multiple machine types on these drives depending on the individual size and ground type to ensure successful construction of each individual line.

Rob Carr General Manager, Angelo Soumboulidis, said the company was able to provide a novel design solution to the land restrictions by extending individual pipeline lengths. This technique was able to provide the most cost efficient construction method for QUU.

Sophistication in large diameter pipeline inspection

Interflow, through its partnership with Drain Surgeons NZ and Cleanflow NZ, is now able to offer Australian water authorities a sophisticated large diameter pipeline inspection system that is capable of providing accurate, objective data on the condition of pipeline both above and below the water line.

The HD Profiler operates without person-entry and without the need for flow control by utilising CCTV, laser profiling and sonar. This advancement represents a major step forward for clients who seek a safe, cost-effective and objective means of understanding the condition of their large diameter pipelines.

The HD Profiler allows sewer pipes in the size range 900 to 3,000mm to be inspected without person-entry. The unit contains a camera, laser profiler and sonar. It is pulled through the sewer at speeds of up to 15m per minute and can survey a pipeline from a single access point up to 3,000m long.

The unit stores all information on board. Upon retrieval the data is downloaded and sent to Cleanflow NZ for analysis and preparation of the reports.

All data collected from the HD Profiler is sent to Cleanflow for analysis, where a comprehensive set of reports are generated. In addition to the CCTV video files, Flat Graph reports, debris reports and laser profiling, a condition assessment report is provided which not only provides an analysis of that moment in time but also allows for subsequent comparisons when future surveys are carried out, which in turn can allow for rates of change to be determined.

See it all at International No-Dig 2013

The benefits councils and utilities can enjoy through utilising trenchless technology are many and varied – cost savings, environmental benefits and community satisfaction are just the tip of the iceberg.

In 2013, the international trenchless community will gather in Sydney for International No-Dig 2013, a comprehensive conference and exhibition being hosted by the Australasian Society for Trenchless Technology (ASTT) and the International Society for Trenchless Technology (ISTT).

International No-Dig 2013 will take place at the Sydney Convention and Exhibition Centre and will be staged from the 1st to the 4th of September.

The conference program will feature acclaimed international experts on rehabilitation and installation, Super Panels that will tackle contemporary trenchless issues, speakers who have worked on recent large No-Dig projects the world over, and streamed technical sessions.

The impressively sized exhibition will showcase all the latest and best trenchless products and services on the market.

By coming along to International No-Dig 2013, council and utility employees will learn about the cutting edge in trenchless technologies, and meet suppliers, manufacturers and contractors to discuss how these technologies can be used on current and upcoming projects.

Residents are increasingly becoming aware of the environmental, social and economic impacts of major infrastructure projects taking place in their communities, making these factors a priority for councils and utilities planning major works. Trenchless technology is providing effective solutions to many of the challenges that can present themselves.

Council and utility employees involved in planning major works and asset management will benefit from attending International No-Dig 2013 and seeing the solutions trenchless technology can offer first hand.

 

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Microtunnelling works, part of QUU’s Deebing Creek Project.

Last modified on Monday, 25 February 2013 14:14

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