The $200 million Deloitte Centre at 80 Queen Street Auckland will open October 2009. It is a brilliant junction between old and new – blending modern architecture with the historic 1930’s street frontage of the Jean Batten Building. The scale of the 21-level tower, its sophisticated green technology, and ingenious use of steel beam construction make it a New Zealand first.

The Deloitte Centre is a great example of how steel offers significant benefits in modern construction, particularly in city sites. The use of steel beams solved time and site constraints and was the flexible choice in achieving the architectural vision – creatively, technically, and practically.

Nick Clements of Steltech Structural Limited explained, “With Steel you can produce a much slimmer structure than concrete columns and beams, so it allows more floor space and a lighter feel to the whole structure. It also reduces the overall mass of the building which reduces the size and cost of
the foundations required. It is faster to erect, as there is no requirement for formwork or the time to cure concrete. Much of the steel fabrication is done off site so it reduces the manpower and time on site – making for a safer smoother flowing worksite.”

A major construction issue of the Deloitte Centre was the need to ensure that the building fitted with the facade of the historical Jean Batten Building. The old building’s stud height remains 2.7m yet sophisticated ceiling services have been installed through custom made welded steel beams.

Modern multi story buildings tend to have greater heights between floors due to the need for installing air conditioning and other services. With traditional construction methods the services would have to pass under the floor beams, but with welded steel beams the designer can pass services through the
beam webs saving this height.

Significant use of cut outs in the beam webs means all the services tucked neatly in the ceiling space with large ducts going right through big beams.

Steltech worked closely with the fabricators, D & H Steel Construction.

“The fabricator supplied us with electronic files for each different beam design that we fed through to our CNC profile-cutting machine to cut the holes,” Clement said. “Designers can now push how they use steel by thinking outside the square on how welded beams can be made to almost any shape
or size and with holes pretty much wherever they want them.”

Possibly the most powerful first impression to all who enter The Deloitte Centre is a result of the dramatic steel cantilever in the foyer. The long spanning capability of steel enables the creation of large and graceful areas of unobstructed space in multi-storey buildings. Here the effect is extraordinary. The architects, local firm Warren & Mahoney and international company Wood Bagot, have achieved their goal of a stunning urban frontage.

“The glazed canopy on Queen Street not only provides shelter to the footpath along the building boundary but is also a striking element at the main entrance. The primary structure consists of a 900mm deep steel box beam, which is 42 metres long. At the main entrance the dramatic box beam cantilevers a total of 12 metres. The glazing is supported off 14 large polished stainless steel arms, which in turn hold the canopy’s stainless steel spider fixings,” said Richard Voss, architect from Warren & Mahoney.

The whole building is based on pushing design boundaries from conventional to very modern, with the lowest possible environmental impact. As a result The Deloitte Centre is a smart and efficient building worthy of its 5 Star Green Star rating from the Green Building Council.

The double ventilated façade on Queen Street is part of the project’s “Green” objectives. As Voss explained, it reduces the solar gain on the West facing façade by virtue of the stack effect. The warm air rises in the 600mm wide glazed cavity to outlets at high level. Computational Fluid Dynamic (CFD) modelling was undertaken to predict the air movement speeds and heat patterns within the double ventilated façade. It will efficiently keep the tower warmer in winter and cooler in summer. Another green feature is the harvesting of rainwater from the building. This will be used to flush the toilets. Also, upper level interiors have 2.9m
studs reducing the need for artificial lighting.

Overall, The Deloitte Centre shows how steel construction offers new solutions and opportunities for architects to cost-effectively expand their artistic expression and meet today’s challenges for inspiring, smart, efficient, safe buildings.