LIGHT TECHNOLOGY

New, lighter prestressed concrete products are allowing architects and engineers to specify longer spans and even add more floors to multi-level developments
View of Stahlton Engineered Concretes new office and metal, black
View of Stahlton Engineered Concretes new office and products.

Until now, the long spans favoured in many largeprojects have required substantial concrete flooring systems to cope with the load, and propping on site.

It's a situation that Dave Edkins, national technical manager of precast and prestressed concrete specialists Stahlton Engineered Concrete, knows all about. As part of the company's research and development programme, he's talked to dozens of consulting engineers, developers and architects about the issue.

The result is a new type of hollowcore product: 150mm hollowcore prestressed concrete with a 65mm topping that provides for bigger spans than achieved by 100mm flat slabs, without the need for heavier 200mm hollowcore. The new hollowcore, pictured overleaf, also meets national sound transmission class (STC) and fire resistance ratings (FRR).

It's a development that has a few unusual design features, says Edkins.

"Because of the way we've designed it, timber formwork can be placed alongside each piece of hollowcore, which reduces costs and uses less concrete. It also provides a clear working surface from beam to beam, so there is no need for expensive temporary propping systems on site," he says.


View of Stahlton Engineered Concretes new office and apartment, architecture, balcony, building, facade, house, neighbourhood, property, real estate, residential area, window, brown
View of Stahlton Engineered Concretes new office and products.

The 150mm hollowcore sits alongside the company's other hollowcore products, its rib and infill systems used as an architectural feature in Stahlton's new office in Auckland and its Double Tee prestressed concrete system, shown overleaf, which recently passed independent loadbearing tests by BRANZ.

Some of its products are custom manufactured for projects, says Edkins.

"For the E2 retail project in Albany, we used bridge beams, modified from 950mm deep to just 400mm, so that the building can incorporate 18m spans and still retain a slender floor profile. At Westfield Albany, we supplied half prestressed beams, which allowed for wide spans and needed fewer props."

Recent large projects handled by the South Island offices include Mercy Hospital, Waikouaiti Community Centre and Dunedin's Zoology building, says southern manager Stuart Ashby.

"We have a busy programme of forward work in the South Island. The Kawarau Falls Station, the new stand at AMI Stadium and the new domestic terminal at Christchurch Airport are the most significant," he says.

View of Stahlton Engineered Concretes new office and roof, white, black
View of Stahlton Engineered Concretes new office and products.

Stahlton provides prestressed and precast products throughout the country, as a result of an acquisitions programme by parent company Fulton Hogan. The programme saw plants in Mount Maunganui, New Plymouth, Bulls, Christchurch, Cromwell, Hamilton and Otaki joining the team.

Two national support offices, in Auckland and Christchurch, provide technical support to staff and customers throughout the country.

The design team offers obligation-free advice on precast and prestressed concrete design, proposals, preliminary drawings, cost estimates and specifications. It's an expert service that supports customers across New Zealand, says national manager Ian Finlayson.

"With our recent acquisitions, we can offer national coverage, with high levels of technical expertise and innovation across our precast and prestressed concrete products," he says.

For more information, contact Stahlton Engineered Concrete, 0800 Stahlton (782 45866) or visit the website: www.stahlton.co.nz.

Mar 28, 2008
We know the specialists