As our utility assets age and the demands on them increase, asset managers are faced with the decision of whether the replace or renew their critical infrastructure. 

Why replace when you can renew?  

This is a fundamental question facing our utilities and asset owners, as our ageing infrastructure starts to show signs of age and stress. As our population increases, the demands on utility assets are constantly increasing, and meanwhile, critical planned maintenance programs are being sidelined in the continual drive for cost savings.

Pipes, culverts, tunnels and sub-surface access conduits are all prone to damage and degradation, and with the addition of today’s traffic and loading – factors that were never conceived at the time of the asset’s original design – planned maintenance programs need to be developed if these assets are to remain intact and serviceable in the years to come.

Regardless of how these structures were originally constructed, like the above-ground infrastructure that they sit under, regular maintenance is required, and from time to time major upgrades are necessary.

The cost of replacing underground assets is high, and inevitably new construction causes large scale disruption in the near vicinity of the work. Replacing assets also often carries an unacceptably high carbon footprint, which impacts on the environment and community.

Renewal options

Several remedial systems exist in today’s market that are designed for the small bore, non-man entry market. These are generally classified as flexible linings but are frequently offered as proxy structural solutions for larger profile culvert and tunnel repairs. Whilst these solutions can be suitable for small sections they are not always appropriate for larger remedial proposals, and are nearly always limited in the lengths that they can be applied to without surface intervention – which then almost always means excavations from the surface. To avoid asset usage disruptions and open-cut intervention costs, culvert and pipe remediation over 1,200 mm generally requires a different approach, as structural integrity poses higher demands to deliver effective designs with a design life of 75 years or more.

ITS PipeTech, who have offices in Sydney, Brisbane and Perth, specialise in pipe renewal and culvert renovation throughout Australia and offer several best practice technologies to address these issues. These state-of-the-art remediation solutions achieve an acceptable stand-alone structural lining without the need for open-cut replacement, therefore avoiding issues such as cost, impact on the community and environmental concerns.

ITS PipeTech offers a cured-in-place-pipe (CIPP) relining solution for pipes and culverts up to 1,500mm (the Berolina liner system), and a reinforced steel and concrete solution (Tunneline) for large diameter rehabilitation projects. Tunneline was designed in accordance with AS5100.2 and has been used extensively under road, rail and other types of infrastructure. ITS PipeTech has been successfully using Tunneline as a solution to the ever-increasing problem of our degenerating and aging infrastructure issues.

Before – 3.6M Twin CSP

Before – 3.6M Twin CSP


4900mm Final Rehab

The Tunneline solution

Tunneline is an innovative reinforced concrete lining technology developed in the UK and used extensively to upgrade and maintain crossings under roads, railways and waterways, as well as for drainage remediation for the past 30 years.

Tunneline is a one pass operation and requires little or no pre-works to stabilise the existing host condition. It is able to line most existing profiles (circular, box, ovoid and so on) and will also accommodate vertical and horizontal bends as well as size and shape transitions within the existing host structures. It can be used to line all known culvert materials in a size range from 1,200 to 9,000mm. Tunneline can be designed as a stand-alone structure or as a composite form, where a factor of the existing host tunnel is taken into consideration in the final design. It is designed to withstand the external ground loading and traffic loads from both road and rail under limit state conditions to AS5100, and can also be designed to cater for internal pressure loading up to 64 Bar, where the conduit is used as a transit for pressurised liquids. The system is also able to line vertical shafts, tanks and chambers as well as horizontal and inclined culverts.

In comparison to conventional rehabilitation methodology, such as GRP or PVC/PE systems, Tunneline is a one-stage operation and compliant with AS5100 offering a quicker, stronger, and more cost-effective solution. It is installed without having to excavate access from the surface and expensive transport costs associated with the delivery of traditionally used liners and product to site are eliminated.

In Australia, ITS PipeTech has completed 22 projects with Tunneline, and is currently working on another three projects totalling over 2,300m. The size of these vary from 1,200 to 5,600mm and profiles have been circular, square, oviform, elliptical and rectangular, with host substrates comprising of brick, concrete, CSP and CSU constructions.

Globally, Tunneline has been used to complete over 850 separate projects with over 400km of assets successfully rehabilitated.

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