Project: Tugun Bypass, Queensland

In addition, two primary features of environmental mitigation on the route were the relocation and translocation programs, including the successful relocation of approximately 10,000 fish. As part of additional commitments to mitigate the environmental impacts of the bypass, fish-friendly culverts were installed to mimic the flow rates, size, path and structure of the existing drainage line.

Environmental commitments also included provision of compensatory habitat for local fauna. Australian animals such as the sugar glider and squirrel glider have been provided with nestboxes made from recycled hardwood to replace hollows taken from clearing works. Each nestbox has specific dimensions and styles designed to dictate which animal can enter.

In this way, the Alliance targeted nestbox placement based on the hollows removed from within the bypass alignment, and the species known to occur in the vicinity. Monitoring has shown half of these nestboxes provide valuable shelter for species including sugar gliders, squirrel gliders, brushtail possums, rainbow lorikeets, owlet nightjars and wood ducks.

Tunnel to task

On an engineering level, the tunnel was designed to be protected from a one-in-a-hundred-year flood, which required the construction of floodwalls surrounding the tunnel to prevent water flow into the tunnel. Large concrete tanks beneath the tunnel ramps collect rain run-off or water from the emergency deluge system within the tunnel area. The excess water is pumped into nearby sedimentation basins.

If the Tugun tunnel is closed for any reason, the intelligent transport system automatically redirects traffic to use the Gold Coast Highway route. An incident response group, including representatives from Queensland, NSW, the airport and emergency services, has developed and tested integrated incident response procedures.

Safety features in the tunnel include:

• Emergency broadcasts through the radios of vehicles in the tunnel.
• Electronic message boards to deliver important safety messages about changed traffic conditions.
• Identified emergency exits, fire extinguishers and emergency phones located at intervals through the tunnel.
• A water deluge system for use in the event of a major fire.
• Jet fans to maintain air quality during peak traffic times, and in the event of an incident.
• 24-hour monitoring via closed circuit TV cameras.

Before the construction of the bypass, modelling of future traffic flows showed that by 2017, significant delays of greater than 30 minutes would be commonplace without one. Following the opening of the Tugun Bypass, traffic volumes on the Gold Coast Highway decreased by about 50 percent to 35,000 vehicles a day, of which only 3.6 percent were heavy vehicles.

The 1 millionth vehicle passed through the seven-kilometre link road within a month of opening, and by the first year of operation, 14 million vehicles had travelled on the road. Current monitoring shows that approximately 40,000 vehicles use the bypass everyday, with this figure now expected to rise to 60,000 by 2017.

The project has also gone on to win numerous excellence awards in the Gold Coast, Queensland and nationally from the Master Builders Association, Engineers Australia and the Australian Institute of Project Management.

The awards are recognition for the dedicated team who delivered results beyond the scope of business as usual. Says O’Dwyer: “This project has brought together a dedicated team who deserve recognition for the hard hours and sweat which has been put in to create a journey to remember.”

Road to success

As with many infrastructure projects, the construction of the Tugun Bypass involved a lot of planning, resources and teamwork to succeed.

• Seven kilometres of dual carriageway, with four lanes and provision to upgrade to six lanes in the future.
• 334 metres tunnel underneath the Gold Coast Airport’s runway extension.
• Approximately 800,000 cubic metres of earthworks.
• 90,000 tons of asphalt.
• Pavement construction includes 160,000 cubic metres of concrete of 90,000 tons of asphalt.
• A rail slab was constructed adjacent to the road, allowing for a future rail line from Robina to the Gold Coast Airport.
• Grade-separated interchange at Stewart Road, Currumbin and at the Tweed Heads Bypass, Tweed Heads.