Victory Christian Church Carpark - Infrastructure / Civil

Client:          Victory Christian Church Proparty Trust

Project Brief

Mainzeal’s assignment of clearing the Victory Christian Church site of contaminants has involved using specialist methodology, plant and equipment, seen for the first time in New Zealand.
The Victoria Park Viaduct and Tunnel Project is an Auckland Motorways development designed to reduce traffic bottlenecks and general motorway congestion. It is currently under construction and the project is due for completion in 2012.
The new Victoria Park Tunnel cuts across the corner of property belonging to the Victory Christian Church that is currently used for car parking.
In January 2010 Mainzeal was selected to construct the new underground car park, auditorium extension and administration facility for the Victory Christian Church, freeing up land for the Tunnel Project.
The church is remaining operational seven days a week, so the construction project is being facilitated around the congregation of 600 people.
An added complexity was that before construction of the underground car park could begin, a major excavation exercise had to be undertaken. The site used to be the home of an old gas works so the ground was heavily laden with contaminants and buried concrete structures that needed to be removed.
Strict Resource Consent conditions required innovative environmental controls. This is the first site in New Zealand where all of the excavation has been carried out within an airtight remediation enclosure, and with a dedicated air change and filtered extract requirement. Mainzeal’s in-house experts, together with environmental consultants, have developed specialist engineering controls that ensured all the Resource Consent requirements were met. At the same time the workforce was safeguarded from both airborne contaminants and noxious vehicle fumes.
The largest of the remediation enclosures was a 65 x 40 x 14m high single-span tent. For six months it was easily visible from the harbour bridge. The main part of the enclosure was sourced from Australia with supplementary parts being shipped from California. A dust and carbon filter system was imported from Sydney.
The main construction works involve building the new car park which is on four sub-grade levels. It has an area of approximately 100m x 40m and will provide 344 spaces.
The perimeter of the car park has been formed using 290 secant piles and a further 50 king piles with shotcrete arches. To date 25,000m3 of soil – which includes 15,000m3 of managed/contaminated fill – has been excavated and removed to approved landfill sites.
Temporary bracing to the piles has been provided by 54 anchors, which extend up to 20m in length. To prevent the structure from floating, 112 grooved anchor tension piles have been installed and works are about to commence on a pressure relief drainage system.
The car park will have suspended post-tensioned concrete slabs and beams. Mechanical air handling will be provided by a plenum that will be formed along the perimeter of the building.
Cantilevering off the north-east corner of the car park is a new administration facility. A large gantry will be used to support the building during construction, allowing all church and site traffic to pass below. The administration building has a traditional concrete frame with steel roof structure and is clad in standing-seam zinc. It will be an open plan office area with exposed services.
At the church auditorium Mainzeal is installing new toilet blocks while also demolishing what were the existing toilets, kitchen and foyer facilities to create new meeting rooms and foyer areas. These are predominantly single-storey steel frame extensions, clad in standing-seam steel cladding.