COP Outcome development and evaluation

The air conditioning/mechanical ventilation system also uses the shell beams to distribute air, which is returned via the building cores or a main atrium. The potential for free cooling to high-load areas and for energy efficiency have been maximised.

Stresscrete Professional Services Manager Keith Norgate MIPENZ says that the shell beam arrangement combines a number of building functions and technologies into a single high-performance structural; element. The result is a long-span column-free structure serving 12 metre floor plates, incorporating air supply and extract channels, cable management provision at floor level across the floor plates, a ceiling surface and a stabilising heat sink and source of thermal mass.

In a novel use of these major structural elements, the shell beams, for the complex were manufactured with smooth interiors and installed at close centres to conduct services and air-conditioning ducting.

Another novelty is the use of exposed radial shell beams and infill panels to satisfy architectural requirements, allowing the floor to run smoothly around the curves of the building. Several hundred of these precast beams, each weighing around three tonnes, were delivered to the building site in Glen Innes and lifted by a big Favco tower crane for placement under the supervision of main contractors Fletcher Construction.

This was an unusual project because the beams were exposed, and also because of the sheer number required by their air conditioning role – probably two to three times as many as would normally be used on a project like this. Placement was a time-consuming and painstaking task. Fletcher's Project Manager Mark Ritchie says, "From the constructor's point of view the shell beams were very special and had to be handled with great care. Those with plywood infills needed to be checked for quality control, and each beam had a unique identity."

The plan form of the building has been developed to encourage the use of natural light and ventilation. The large floorplates are linked to the atria and courtyards to provide an optimum balance between space planning, natural ventilation and daylighting provision.

Courtyards act as sunny summertime meeting spaces while the main atrium provides a similar sheltered facility in winter. The atria also promote natural ventilation, utilising the stack effect from temperature differences and venturi effect from the airflow across roof outlets.