Worldwide Parking Group Ltd has developed an innovative precast concrete system for car parking buildings around New Zealand that offers a range of benefits, from design versatility and speed of assembly through to the potential for reuse on other sites.

case study 4_photo2.jpgThe precast concrete system’s most striking feature is the patented demountable connections, which mean that at any given point in time, the structure’s standard components can be dismantled and removed from the site for storage or re-erection on another site.

The technology refines established multi-storey, precast concrete technology by incorporating patented seismic connections and foundation systems, and new concrete mix designs, reinforcement and casting techniques. Rationalising component sizes has also led to efficiencies in cost and planning.

The system uses standardised precast concrete structural components that are assembled without the need for poured or welded connections, utilising patented reinforcement and connections. Innovation in the design of services, structural framework, fixtures, fittings and equipment, also make it possible to achieve rapid and orderly construction.

The precast concrete system was used in the construction of the Nuffield Street car parking building in Newmarket, Auckland. The building has four levels, with provision to add more car parks through the addition of another floor.

The car parking building has about 320 components, manufactured offsite by Stahlton Prestressed Concretes, Wilco Precast Ltd and Stresscrete. The components include columns, spandrels (which support the floors and act as handrails), and 18-tonne double-T floor pieces, measuring 2.5m wide and 16.7m long. The simple design involves placing the spandrels in rebates on the columns, with the double-T beams sitting over, and being bolted to the spandrels.

The Nuffield Street car parking building is the third Worldwide Parking Group system project completed in New Zealand, following the construction of two domestic terminal car parking structures at Auckland International Airport. The airport was seen as an ideal location to showcase the system’s advantages as the buildings can be dismantled and re-erected as the airport’s plans require.

The first domestic terminal car parking building was completed in April 2004 after a three-month construction period and is a single storey structure for 300 car parking spaces. The first building has performed well and has led to significant developments in the precast concrete system, which have been adopted in the construction of the second domestic terminal car parking building.

These innovative structures will become a more familiar sight as specifiers become aware of precast concrete’s lifecycle cost advantages. Pre-engineered standardised concrete components ensure a low cost outlay, fast assembly, early occupation, minimal maintenance and potential reuse – all benefits which are attractive in a construction environment concerned with sustainability.