HOBAS Pipe of Austria is the world’s only maker of GRP jacking pipe and Global Pipe is Australia’s exclusive agent for HOBAS pipe. Managing Director of Global Pipe Andrew Holman spoke with Trenchless Australasia about the advantages of using HOBAS jacking pipe in the installation of underground infrastructure.
Pipes for jacking are subject to very high loads during installation. The quality of the surface, the jointing system, as well as the physical property of the pipe is important for the successful use of pipe material. Following the installation, the pipes must meet the hard requirements of day-to-day operations – the pipes must be leak-free, corrosion-resistant, have a hydraulic smooth interior surface and be flush safe.
What are the advantages of HOBAS jacking pipe?
The HOBAS pipe consists of a thermosetting composite material. During the automated centrifugal casting process, several components of the compound material are fed into a rotating mould, degasified by rotation with a pressure of 30 to 50 bar, compacted, and tempered.
Mr Holman said that the pipe has many advantages. “Of particular interest are the lower machine costs and reduced excavation due to the smaller outside diameter that is a by-product of the thinner pipe walls.”
A smaller drill hole automatically means that less ground material has to be removed, transported and disposed. The result is considerable savings in excavation work that can amount to 14 to 53 per cent depending on the nominal diameter. The smaller drill hole will often translate into reduced boring costs.
The other major benefit is the inherent flexibility in GRP Mr Holman said “The pipe is able to compensate for minor irregularities in the face of the machinery or bore by means of elastic deformation. This elasticity also means that no wooden spacer rings are needed in the joint.
“The use of wooden spacer rings should be considered the weak link in any jacking project as the wood is left behind and will swell in the joint and deteriorate faster than the rest of the pipe system.”
The HOBAS jacking pipe will work well in any pipe jacking or boring project. Mr Holman said that the pipe is particularly cost effective in projects where the jacking/boring is happening in rock. If there is a high boring cost due to the geology, then there is typically a major savings by having a HOBAS pipe that meets the criteria of the internal pipe diameter but has a substantially smaller external diameter due to its thinner pipe wall, Mr Holman explained.
Stage two of the Epping Branch sewer in Victoria will use DN1000 GRP. The project will begin in April-May 2009. The Epping sewer combines 1,143 metres of open trench and 877 metres boring using HOBAS jacking pipe. The ground condition for the bore is mostly solid basalt. The contractor on the project is MFJ Construction.
Anthony Caligiuri from Califam Construction, a customer of Global Pipe, said he was very pleased to see HOBAS jacking pipe available in Australia. Mr Caligiuri said it is his preferred pipe choice. “The advantage is the thinner wall, which significantly reduces boring costs.” Mr Caligiuri has a number of jobs earmarked for the GRP pipe.
The pipe is available Australia-wide in diameters from DN200 up to DN2100.