Zero 4, Plymouth

Concrete was the first choice for the structural frame. The footprint was angular with the complex consisting of one nine storey and one ten storey block. The original concept of property developer, Prestige Homes, was for identical luxury flats throughout.

A change in the local housing market changed this requirement and the design conditions could only be met by using Slimdek®. The two key components are at the heart of the Slimdek® system. Asymmetric Steel Beams (ASB) have lower flanges significantly wider than the top flange. These lower flanges support a thin steel profile deck that acts as both permanent shutter and tensile reinforcement to the completed floor.

On the Zero 4 Development Project, Corus supplied the ComFlor® 225 profile, which can be used for slabs up to 400mm deep and clear unpropped spans of up to 6m. Conveniently, most sections of the Zero 4 Development Project had spans of 6m, although in a few locations the complex grid stretched the span to 6.7m. Floor depth was 320mm, main floor beams were 280mm deep ASBs. Around the floor perimeter and the entrance hall the edge beams are formed from torsionally stiffer 250mm x 150mm RHS with shelf angles welded on. Some 400t of ASBs were needed, along with around 10,000m2 of ComFlor® 225.

In all, Prestige Homes estimates that around 12 weeks has been slashed from the original construction programme by going for the steel alternative. This has major implications for the developer’s investment programme. Final completion is now scheduled for mid 2008.