Brisbane Bypass Clem Jones M7 Tunnel
The challenges
M7 Clem Jones Tunnel (CLEM7) known during its development as the North South Bypass tunnel provides local commuters with a connection through the city, a link to the Airport M7 and under the Brisbane River. The high profile project and longest road tunnel in Australia at the time of completion features a 4.8km twin two-lane tunnel which sees around 60,000 vehicles per day.
With world class safety and emergency systems, naturally the consideration of commuter and neighbouring community noise was a factor when developing the site.The ventilation shafts and stations are part of the buildings of the North South Bypass Tunnel network that serves as a system for safe tunnel ventilation and as an emergency system for extraction of smoke out of the tunnel during a fire emergency. It includes 41 connecting egress tunnels for use in emergencies.
The further problem was to find a product that had high acoustic performance and yet could withstand the issue of contamination, weather aging and at the same time be fire safe to a non-combustible level.
The road surface is concrete, not bitumen so reflected noise could potentially be amplified further so high absorptive properties were required.
The solutions
Reapor offered a unique solution. Fixed with a cement render to maintain fire rating the ventilation shaft plenums were lined with Reapor to control the escape of reflected noise. The key benefits of high NRC being .90, non-combustible and unaffected by weather pollution or moisture made it an ideal choice to solve the problem.
The results
Being easy to install directly translated into time saved during construction, with the resulting performance exceeding expectations and reducing the emission of traffic and ventilation noise to an acceptable level. This high profile project was supplied with good results.
