Through collaboration with Interflow, Channeline provided a customised solution to renew the Amarina culvert in Mooloolaba, Queensland.
In 2020, the Sunshine Coast Council’s Stormwater Management Asset team found a large reinforced concrete box culvert located at Amarina Avenue was experiencing severe spalling and corrosion and needed urgent renewal.
A culvert is a structure that channels water and is typically made from a pipe, reinforced concrete or other material.
Measuring at 2.1m by 2.1m with a length of 37m, the Amarina culvert takes run-off from the Sunshine Motorway to the Mooloolaba Canal.
Constructed in 1975, the culvert’s reinforced concrete structure was found to have an environmental exposure rating of “most aggressive” due to severe spalling and corrosion of its reinforced concrete structure.
Interflow considered options to line the box culvert with a large pipe or smaller box sections or to excavate and replace the culvert, however, they each offered compromises.
As the culvert passes under a busy street, the renewal solution needed to limit disruption to the community during construction and reduce impacts to flow capacity.
Enter Channeline with its tailor-made solution.
The solution
Since the 1980s, Channeline has provided bespoke structural glass reinforced plastic (GRP) lining systems.
Due to its versatility and customisation, the Channeline solution is a fully structural rehabilitation solution for the trenchless rehabilitation of sewers, tunnels, culverts, stormwater and other buried structures.
Channeline employs the mechanics of sandwich panel design, incorporating a unique polymer and aggregate core within its GRP liners.
How it works is simple.
The first two layers of Channeline GRP, which are the surface and barrier layers, incorporate a corrosion barrier. This is manufactured from high-grade surface veil, precisely impregnated with resin, followed by several layers of multi-axial engineered fabric and glass fibres.
The next layer is a central core, composed of sand and resin, which is evenly applied to the exact thickness required.
The following layers are formed using multi-axial fabric, glass fibres and resin.
This outer surface is treated with a bonded aggregate to enhance adhesion to the annular grout.
This is used during the installation phase.
The patented technology means that its product is thinner than standard GRP, while still achieving the required strength, making it an ideal renewal solution for the Amarina culvert.
Rather than using a solution which required excavation, Interflow opted for Channeline and imported custom designed and manufactured GRP box-sections that fitted tightly into the existing culvert.
Rehabilitating an existing sewer or culvert is dependent on the cross-sectional area as well as the roughness of the pipe.
This can lead to a reduction in the cross-sectional area as well as flow capacity.
However, with Channeline, the surface texture of the rehabilitated pipe has shown to improve flow capacity.
As it is also thinner than standard GRP liners, less cross-sectional area is lost.
For the Amarina culvert rehabilitation project, the Channeline smooth internal surface reduced friction, meaning there was no loss of flow carrying capacity and very minimal cross-section was lost.
Critically, installation of the Channeline solution required no excavation and no need for tree removal. This offered a substantial cost saving for the Sunshine Coast Council.
Over the course of 12 days, Interflow implemented the custom-made Channeline solution and successfully renewed the Amarina culvert with no environmental incidents and minimal disruption.
Now, the renewed culvert is expected to have a service life of over 100 years. Through the use of Channeline and its innovative and sustainable GRP solution, Interflow and the Sunshine Coast Council have saved costs and reduced community impacts on a complex culvert problem.
For more information, visit Channeline.
This article featured in the August edition of Trenchless Australasia.
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