Tugun Bypass Motorway

Tugun Australia



Main Roads

Main Contractor:


Pacific Link Alliance consisting of
Main Roads, SMEC Pty Ltd and AbiGroup Pty Ltd

Foundation Contractor:


BAUER Foundations Australia Pty Ltd

Scope of work:


16,500m2 Diaphragm Wall with width 1000mm and up to 27m depth 
and 3,200m2 (60 nos.) Barrettes with width 1000m and 19m depth.

Construction Period:


April 2006 – October 2006


To ease traffic congestion at the Tugun merge of the Pacific Highway and the Gold Coast Highway a new motorway was constructed. The Tugun Bypass project is a high standard 7km road link between the southern Gold Coast region and northern New South Wales. The $360m project includes a 400m tunnel beneath a proposed extension of the Gold Coast Airport main runway.

For construction of the tunnel two 400m long diaphragm walls were designed; one wall for the northern side of the carriageway and one for the southern side. In the centre line of the tunnel 60 barrettes were installed using the diaphragm wall method. As the construction of diaphragm walls is a very specialized procedure, this part of the project was assigned to a Sub-Alliance, which was made up of a joint venture between Bauer Foundations Australia and Piling Contractors. 

Because the extension of the runway for the Gold Coast Airport was proposed over the new bypass, it was necessary to construct the tunnel under the new runway. As the site of the new tunnel is directly in the flight path of the adjacent operational airport, headroom restrictions applied due to taking off and landing planes. The Obstacle Limitation Surface (OLS) that was imposed by the Gold Coast airport varied from 6.5 to 12.5m.

Special equipment was necessary to comply with the headroom restriction near the airport. Bauer Foundations Australia could provide a low-headroom grab, a special BAUER CBS 25 low headroom cutter as well as other low-headroom equipment (e.g. Tremie pipes). Reinforcement cages were installed in 3 or 4 sections to make up the 19m and 27m cages, respectively. In order to connect the roof and base slab to the diaphragm walls at a later stage coupler boxes were mounted onto the cages.