View the latest trenchless technology tenders

View the latest trenchless technology tenders

Domestic wastewater pipeline renewals 2021/22 
Issued by: Gisborne District Council
Closing Date: 10 December 2021
Location: New Zealand
Description: The request for proposal is an invitation to suitably qualified suppliers to submit a proposal for the renewal of existing domestic wastewater pipeline (trenchless).

Horizontal directional drilling to provide services to Horsham Nature Play Park
Issued by: Horsham Rural City Council
Closing Date: 10 December 2021
Location: Victoria
Description: Horsham Rural City Council invites you to provide a quotation for the installation of horizontal directional bore for the water, electrical and waste services for the Horsham Nature Play Park.

Sewer and stormwater mains lining
Issued by: Hunter Water Corporation
Closing Date: 16 December 2021
Location: New South Wales
Description: The work under this contract includes, but is not limited to, the rehabilitation of gravity sewer and stormwater mains by the installation of lining systems to restore structural integrity, prevent infiltration and exfiltration, eliminate root ingress and/or restore the hydraulic capacity of the mains.

The gravity sewer mains to be rehabilitated will be from a nominal diameter of 150 mm up to a maximum of 600 mm. The stormwater mains to be rehabilitated will be from a nominal diameter of 750 mm up to a maximum of 1050 mm.

Big Rivers Region, Central Arnhem Road, provision of water bore drilling services
Issued by: Department of Infrastructure, Planning and Logistics
Closing Date: 15 December 2021
Location: Northern Territory
Description: A general outline of the work to be carried out under the contract comprises of drilling and casing of two new road construction water bores on Central Arnhem Road for prioritised upgrade works at Mountain Valley and Mainoru.

Pipeline duplication contract administration, inspection and verification services
Issued by: Townsville City Council
Closing Date: 15 December 2021
Location: Queensland
Description: RRD2DWTP Pipeline Duplication Contract Administration, Inspection and Verification Services

Country South Water Retic Renewal Program
Issued by: Water Corporation
Closing Date: 15 December 2021
Location: Western Australia
Description: Water Corporation is inviting organisations with suitable experience, capability and capacity to submit a Bid for our Country South Water Reticulation Renewals Package for sites in Narrogin and Wagin, Western Australia. The scope of work requires the supply and installation of DN100/DN150 Series 2 PN16 PVC-M water reticulation main and associated works.

Panel of providers for stormwater CCTV
Issued by: Hobart City Council
Closing Date: 08 December 2021
Location: Tasmania
Description: Panel of providers for closed circuit television (CCTV) inspection and cleaning of stormwater infrastructure.

Each fortnight, the Trenchless Australasia e-newsletter includes a list of tenders relevant to no-dig contractors, suppliers and manufacturers.  

The information is provided by Australian Tenders, which is renowned for being an Australia-wide locally owned and operated tender notification service.  

Australian Tenders is also offering readers of Trenchless Australasia three months free on their subscription plans.  

Email support@australiantenders.com.au for more information.  

For more tender information visit the Australian Tenders website

Bohrtec machine guides sewer works

Bohrtec machine guides sewer works

In 2019, Downer Pipetech was engaged by Sydney Water to install 870 m of 226 mm uPVC sewer main for the future developments in the Spring Farm residential area of New South Wales.

With the project requiring the completion of 10 under bore sections, Downer engaged auger boring specialist Bortec Laser Bore from Narellan NSW, which uses machines from expert German supplier Bohrtec.

During consultations with experts from Germany, it was noted that geotechnical reports indicated displaceable soft sand, non-displaceable stiff clays and soft sandstone would be encountered.

These ground conditions suited either the Bohrtec pilot tube system for the displaceable soil, or the Bohrtec 406 mm FrontSteer system for the non-displaceable ground.

Although Bortec Laser Bore possessed both a Bohrtec BM 400 LSC and a Bohrtec 400 LS, it was decided the LSC machine would be better suited to the launch shafts due to its more compact design.

Bohrtec machine guides sewer works
Pits 10 and 11 – shoring boxes 6 m x 3 m; FrontSteer method. Image courtesy of Bohrtec

Challenges

While the project proponents had top-quality Bohrtec machinery at their disposal, the works were not without their challenges and a range of equipment was required.

The required bore lengths ranged from 69 to 111 m and encompassed a total of approximately 830 m of boring across the project, while the launch shafts ranged from 6 to 13 m in depth.

Due to changing ground conditions, the pilot tube method was used in the softer displaceable soil, and the FrontSteer method was used in the harder non-displaceable clay and soft sandstone areas.

This method has both vertical and horizontal steering capabilities with an accuracy of up to ± 25 mm for drive of a length up to 100 m.

The connection point for the sewer was into an existing sewer access chamber 13 m deep in the middle of a roadway.

Bortec and Downer discussed the possibility of directly boring into the existing manhole and eliminating the excavation of the roadway to a connection, and Downer agreed to set up a platform in the existing access chamber in the roadway and internally core out a 600 mm core hole where the bore was to come out.

Bortec was able to use the pilot system to move through the soft sand and, with the use of the optical guidance system, could come out directly in the centre of this core hole.

Afterwards, the hole could be upsized and bored in the 406 mm steel pipes.

Manholes up to 13 m deep were constructed with tight access, with flat grades ranging from 0.45 per cent to 0.65 per cent with minimal tolerances between the bores.

A DN 406 mild steel casing was installed, with the DN 225 uPVC carrier pipe then inserted inside.Centralisers were also installed at 3 m minimum intervals, while the annulus between the uPVC and steel casing pipe was grouted.

Vacuum testing and CCTV of the installed sewer were conducted and all spoil and slurry from the launch pit was removed.

The project was completed successfully and within budget, with no recorded safety incidents, while the connection made to the existing access chamber was made without the need to excavate the surrounding roadway.

Thanks to the technical assistance from Bohrtec, the optical guided system was successfully employed when using either the pilot tube or FrontSteer systems in order to maintain grade and alignment as per design.

For more information visit the Bohrtec website.