Panels to cut motorway noise for St Marys Bay

The first of about 500 acrylic soundstop sheets is put in place. Photo / Steven McNicholl

The first panels are up in a central Auckland motorway project to reduce noise and bird deaths on the roads.

Darren Utting, of the Victoria Park Alliance, said yesterday about half the transparent panels were installed in the job at the foot of St Marys Bay.

Bird deaths will be reduced by guards which are incorporated into the see-through panes as part of the $340 million motorway job.

Motorway experts say birds considering flying towards the wall, thinking it is air, will change their course when they see the barrier.

The Transport Agency said bird mortality rates were a big consideration when materials were chosen for the wall.

"The panels will be treated with Bird Guard - embedded horizontal stripes between the acrylic layers that provide a visual barrier, deterring birds from flying into the otherwise transparent material and injuring themselves," the agency said.

The wall is being built beside the motorway through St Marys Bay near the Fanshawe St on-ramp, south of the harbour bridge.

The agency said this would ensure that the pohutukawa-clad cliffline alongside the new Victoria Park tunnel remained visible because it was an important feature of Auckland's landscape.

"It is the first time the technology has been used in New Zealand," the agency said.

Piling for the wall was done last year and foundations were laid for the barrier which will be about 500 acrylic soundstop sheets. The agency said the panels offered high transparency and resistance to weathering and ageing.

Each panel will be 2m wide but heights will vary depending on where they are installed beneath the cliff edge.

"According to the manufacturer, the acrylic sheets are 11 times more break-resistant than window glass of comparable thickness, making them a better option than safety glass and ensuring they meet all the safety requirements for noise control materials," the agency said.

The panels were tested in a trial run late last year.

When the job is finished next year, the tunnel will have three northbound lanes. Southbound traffic will use the entire Victoria Park flyover.

ON-RAMP CLOSED

The Fanshawe St on-ramp to the Northern Motorway will be closed from midnight on Friday but will be open again by 5am on Tuesday. Traffic leaving the CBD heading north should use the Wellington St or Curran St on-ramps.

Northbound motorway lanes between Nelson St and Fanshawe St will be closed next Tuesday, Wednesday and Thursday nights and some nights the next week for resurfacing the Victoria Park flyover. It is normal motorway maintenance and not part of the Victoria Park Tunnel project.