The Australasian Society for Trenchless Technology is holding its final webinar of the year on 25 November, on the subject of The Gold Coast Seaway Project – Works Design Challenges and has again kindly extended the invitation of the free webinar to ATS members.

The webinar will be a joint presentation by Barnabas Ilko, Principal Structural Engineer and Trevor O’Shannessey, Principal Geotechnical Engineer from Golder Associates. It will be held on Thursday 25 November from 1-2 pm AEDT.

Presentation overview

The City of Gold Coast required an upgrade of the existing recycled water release system at the Southport Seaway, to accommodate continuing population growth. The project solution included a pipe capable of transferring 6,300 l/s of recycled water from the mainland across the Broadwater seaway via a marine pipeline to an outfall located off South Stradbroke Island.

In order to protect the waterways from environmental impacts, an alternative construction method to the original dredged pipeline plan was proposed by the builder John Holland and their specialist subcontractor Bothar Boring and Tunnelling Australia (Bothar). This alternative adopted trenchless construction using micro tunnelling methods.

The project involved the tunnelling of two  separate drives, the first being a 1385m length of bored tunnel beneath the Broadwater Seaway between Quota Park on the mainland and South Stradbroke Island. It included the construction of two deep shafts and a 2.5m (OD) reinforced concrete carrier pipe that was installed with pipe jacking techniques.

The second drive involved a trenchless 617m crossing between Quota Park and O’Connell Park, including a section beneath Biggera Creek that was constructed using pipe jacking and micro tunnelling using a 1.94m (OD) glass-reinforced plastic pipe.

Golder was engaged by Bothar to join the project team and provide temporary works design support, design services for the tunneling works, construction support that included site attendance across both drives. This presentation will discuss some of the challenges from the designer’s perspective.

As an online attendee, you will be able to attend the webinar from anywhere and will be able to submit questions that will be answered at the end of the presentation.

View the webinar using this link.

If you experience difficulties in joining this free event, then please email Jeff Pace, ASTT Secretary on secretary@astt.com.au for assistance.