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Liner won’t croak after quake

PipeTech provides intelligent and environmentally friendly trenchless rehabilitation solutions that focus on decreasing costs and increasing efficiency.

The company’s AM-LINER II® is a method for rehabilitating damaged wastewater and stormwater pipelines encompassing these qualities and has proven its strength under the most intense environmental circumstances.

PipeTech’s AM-LINER II is manufactured from a polyvinyl chloride (PVC) compound specifically formulated for pipeline rehabilitation and is resistant to all normal sewer effluents due to its superior chemical and flame-resistant properties. It is manufactured in a factory and not in the ground, with the physical properties of the liner known at the time of manufacture rather than weeks after installation.

AM-LINER II provides a cost-effective, minimally disruptive and efficient means of rehabilitating even severely damaged sewer pipes. Once installed, the PVC liner is continuous from manhole to manhole, eliminating leaking joints, root intrusion and further damage to the existing host pipe by corrosive sewer gases.

There are no hazardous chemicals to handle, no noxious odours and no hazardous materials released into the environment, while the smooth interior surface even transitions through offsets to give enhanced flow characteristics to the rehabilitated pipeline.

The PipetTech team busy on site installing the AM-LINER II, designed to withstand even the toughest conditions.

Tried and tested

Following the 2010–2011 Canterbury earthquake on New Zealand’s South Island, the region’s wastewater network was extensively damaged, causing issues for communities affected by the shock. The earthquake showed liquefaction and resulting ground deformations caused major geotechnical hazards to civil engineering infrastructures such as pipelines.

In particular, sewer pipes have been damaged in many areas of Christchurch as a result of liquefaction-induced lateral spreading near waterways and ground oscillation induced by seismic shaking. While most of the damaged sewer and water pipes in Christchurch were in sections made of asbestos cement, several segments of PVC, concrete and polyethylene (PE) pipes were also sheared, pulled out or compressed at various levels, with these damages affecting the sewer network’s functionality in many places.

A study comprising an extensive thesis completed by then-Auckland University student Shyamal Ram investigated the performance of sewer pipes equipped with the AM-LINER II during earthquakes and established its performance as a structural retrofitting measure to earthquake-proof sewer pipes.

The key objective of this research was to analyse the response of buried sewer pipes to liquefaction induced permanent ground deformation, particularly in the transverse direction and was completed by investigating the use of a flexible liner as a potential countermeasure to increase pipe capacity. Underpinning this study was the goal to ultimately retain pipe serviceability following an earthquake, thereby reducing community impacts and rehabilitating the wastewater network.

On average, the AM-LINER II increased the displacement capacity by 191 per cent, with the results confirming the product as an effective countermeasure for sewer pipes in liquefied ground, not only in terms of increased deformation capacity, but also because AM-LINER II can prevent an influx of sand and water through broken pipes. This allows sewer pipes equipped with the liner to remain serviceable even under severe liquefaction conditions.

As a result, restoration of damaged pipes can be delayed so that attention can be provided to more important services or facilities.

Repeat customers

PipeTech has been consistently lining pipes for a range of clients and councils throughout NZ, including Veolia Papakura, New Plymouth District Council, Stratford District Council, South Taranaki District Council, Whanganui District Council, Manawatu District Council, Fulton Hogan (Wairoa District Council), Ashburton District Council, InPipe Logistics (Fonterra) and Port Taranaki.

Manawatu District Council Special Projects Manager Chris Pepper praised the AM-LINER II as a reliable and efficient trenchless product.

“The AM-LINER II is quick and easy to install, is a fully structural product, has a proven seismic response and a demonstrable life cycle well in advance of 100 years,” he says.

“It is fully compatible with other trenchless inspection and repair techniques for sewers, including Later Joint Repair (LJR) products.”

Whanganui District Council Engineering Officer Chris Carter added that the council has used the reliable product since 2011 with no issues.

“Easy and quick to install with seamless lengths of a stable material, WDC have found it an excellent solution to remedy infiltration, root intrusion and structural faults,” said Mr Carter.

Another long-term user of the AM-LINER II, South Taranaki District Council Senior Projects Officer Colin Dudley, said the product allows for the option of “relining over replacing many of our sewer lines, with far less disruption to traffic flow and no road reinstatement required”.

The AM-LINER II is PipeTech’s exclusive product range, with the company being the sole licenced distributor in NZ.

This article was featured in the September 2020 edition of Trenchless Australasia. To view the magazine on your PC, Mac, tablet or mobile device, click here.

For more information visit the PipeTech 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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