Building work on the refit of Heysen Tunnels in South Australia has been completed, with new systems and equipment installed ahead of final testing.
The upgrade addresses tunnel elements that were at the end of their service life after over two decades of use. It also improves safety, traffic management and incident response capabilities.
The Heysen Tunnels were opened in March 2000 and provide a high-speed dual carriageway between Adelaide, the south-east of South Australia and the eastern states. Although constructed to the highest standard at the time, Australian and international standards relating to road tunnel safety have developed significantly since then, so the upgrade brings the tunnels up to current standards.
Project works, undertaken by McConnell Dowell Constructors (Aust) Pty Ltd, include:
- upgrading the tunnel lighting system to an LED configuration
- installing a new automated fire suppression system
- upgrading the tunnel ventilation system
- repairing the tunnel lining and installing monitoring equipment
- upgrading the Intelligent Transport System equipment, including thermal incident detection systems, new and replacement CCTV, Lane Use Management Signs, Variable Message Signage and over height vehicle detection
- upgrading the traffic management system to restrict access to the tunnels in the event of an emergency, and
- upgrading the emergency communication systems, including public address, radio rebroadcast, in-tunnel signage and help phones.
The Australian and South Australian governments committed A$150m (80:20) (US$93.6m) to deliver the Heysen Tunnels Refit and Safety Upgrade, as part of the broader South Eastern Freeway Upgrade.
Among the more noticeable upgrades are the new exhaust fans – eight in the Crafers-bound tunnel and 15 in the Adelaide-bound tunnel. These ‘Half-Banana Jet Fans’ form part of the tunnels’ fire suppression system to disperse smoke in the event of an incident. They will also provide ventilation, control exhaust fumes and clear any fog in the tunnel.
The Adelaide-bound tunnel requires a greater number of fans to allow for smoke or fog to be pushed downhill ahead of traffic. The term ‘Half-Banana’ refers to the slight bend in the fans, to direct airflow along the curved roof of the tunnels.
The project has also included the installation of more than 1,000 LED lights, six overhead gantries, more than 140 CCTV and incident detection cameras, a pair of 400kL water tanks and 60 km of cabling.
Final system testing will continue into early 2025.
