Tunnel to open early to ease bridge queue

Work on the Victoria Park Tunnel is ahead of schedule. Photo / Paul Estcourt

Two of the Victoria Park motorway tunnel's three northbound lanes will open to traffic in November to help ease the queue for the Auckland Harbour Bridge.

Inspecting progress on the $340 million tunnel yesterday, Transport Minister Steven Joyce said: "They've had a good run and work is ahead of schedule."

He noted this was about 15 months earlier than he expected when he turned the first sod on the project in November 2009. It was the first of the Government's seven roads of national significance to be started.

The harbour bridge to the Newmarket part of State Highway 1 was a key bottleneck for one of the country's busiest freight and business routes.

"It will greatly ease congestion for the 160,000 vehicles that use this route each day," Mr Joyce said.

He saw a team of excavators working four storeys below the park within the stout walls of a trench that will soon be totally covered.

A lot of work had been done on the central motorway system, including the Newmarket Viaduct and - opening next month - a fourth southbound lane to the Greenlane interchange.

The minister said he was aware that for North Shore motorists, traffic congestion started at 6.30am.

The project is part of a total $406 million widening of the highway for 2.6km through St Marys Bay.

It calls for the existing Victoria Park Viaduct to be reconfigured to carry four southbound lanes of traffic.

The whole job will be completed in March, said Transport Agency state highway manager Tommy Parker.

Hopes for an early finish took into account major work to make the tunnel road-ready - fitting lights, fire-sprinkler systems and a fire-proof escape corridor along the tunnel's western side.

Bringing the programme forward would mean another closure of the Wellington St onramp to the motorway's northbound lanes.

It would be closed for seven months from May 2 to enable work on a new onramp and the tunnel's southern portal.

He said when the ramp was closed for three-and-a-half months last year it had no significant effect on CBD street traffic and motorway flows improved.

Next week, the Birdcage Hotel will be returned to its original site, which is now above the tunnel.

The twin tunnels proposed for the Waterview section of the western ring route motorway are tubes excavated at depth through rock using conventional mining techniques.

Each end will be lengthened and the grade eased by using the cut and cover method.

THE NUMBERS

$340m cost
450m long, built by "cut and cover" method
3 northbound lanes
2 lanes ready in November
160,000cu m excavated
6-10m deep
360 roof beams
6m minimum headroom
800-900mm thick walls