Vic Park Tunnel, New Zealand

Auckland's Vic Park Tunnel project, the third and final phase in the Central Motorway Junction (CMI) improvements programme, extends 2.2km from Auckland Harbour Bridge through St Mary's Bay and Victoria Park to Wellington Street. The project is expected to be completed by 2012, two years earlier than originally scheduled.

The NZ$406m project includes construction of a three-lane northbound tunnel underneath the Victoria Park, conversion of the existing viaduct to four southbound lanes and laying of additional lanes through St Mary's Bay.

The 440m-long Vic Park Tunnel (VPT) is the first tunnel to be constructed in Auckland. The tunnel is expected to reduce congestion through Auckland’s central motorway.

In December 2004, New Zealand Transit Board decided to construct a northbound tunnel under Victoria Park, based on a community consultation workshop, investigations to improve the motorway section and clear preference given by Auckland City Council, Auckland Regional Council and North Shore City Council.

The tunnel was planned to enhance safety and efficiency of road transport between the North Shore and Auckland and between Central Auckland and surrounding areas. It would also reduce congestion through Victoria Park viaduct and St Mary's Bay during peak hours.

Construction

Pre-construction work on the project began in August 2009, while actual construction started in October 2009.

Cut and cover technique is being used in the construction of the tunnel. It involves digging of a trench, lining it up and placing a concrete roof over the top.Furthermore, the roof will be covered with topsoil and returned as public open space. Construction of the tunnel will result in three additional northbound lanes between the viaduct and the Harbour Bridge, taking the total number to five. Five southbound lanes will also be laid along with a bus lane.

Contractors

New Zealand Transport Agency (NZTA) has selected V-Formation consortium to carry out the $440m Vic Park Tunnel project.

The consortium led by Fletcher Construction includes Beca Engineering, Palmerston North headquartered Higgins Contractor and Australian consultancy Parsons Brinckerhoff.

Project

The New Zealand Government has identified the VPT project as one of the seven Roads of National Significance.

The tunnel project is expected to make road travel less tiresome. It aims at controlling traffic on Auckland Harbour Bridge by regulating the flow through St Mary's Bay and across the Victoria Park viaduct to Wellington Street on the Southern Motorway. It also aims at completely utilising the Harbour Bridge's capacity.

The project also provides better pedestrian links and gives priority to buses. Public transport is expected to get a thrust with the Northern Busway and also with clearance of congestion at St Mary’s Bay. The project will ensure smooth flow of traffic in the afternoon peak hours at the viaduct. A northbound bus lane is planned to be included in future.

Vic Park Tunnel design

The $320m northbound tunnel section is funded by Transit through New Zealand Land Transport. It is designed and located in such a way that it allows a future southbound tunnel to replace the Victoria Park viaduct.

The northbound tunnel has also been specifically located and designed so as not to prevent development of a southbound tunnel.

The tunnel preserves key heritage icons, including the Birdcage Hotel, provides better pedestrian access and manages noise effects by tunnelling and noise walls. Birdcage Hotel will be temporarily moved 40m away, as it is standing in the way of the proposed tunnel. The hotel will be restored after completion of the project.

Victoria Park's open space will be closed during construction and reopened after completion of the project.

St Mary's Bay

Work on St. Mary's Bay mainly includes five traffic lanes each, for southbound and northbound traffic, a bus shoulder lane for southbound traffic and an extension of Shelly Beach over-bridge to accommodate the additional northbound lane.

The bay also includes noise walls along the western edge, a pedestrian over-bridge linking Jacob’s Ladder with the Westhaven area and more open space at HMNZS Ngapona site.

Victoria Park

Victoria Park and its surroundings are not expected to be affected by the increasing traffic as the vehicles will traverse through the tunnel. Further, implementation of mitigation measures will decrease noise in St Mary’s Bay.

The proposed noise mitigation options include quiet road surfaces, transparent noise walls up to 5m in height and improvements to affected properties.

Noise mitigation options will be implemented between Shelly Beach over-bridge in St Mary’s Bay and the Fanshawe Street off-ramp, and in a few areas of Freeman’s Bay.

The project is expected to reduce vehicle emissions, due to ‘stop-start’ traffic flow, by alleviating congestion. In addition, potential build up of emissions will be prevented by ventilating the tunnel.