HERA has successfully completed a comprehensive research and development program with Tata Steel International (formerly Corus New Zealand) in June 2010.

This work has resulted in the addition of three new cold-formed steel floor deck products to their ComFlor 60 and 80 range for steel-concrete composite construction.

These new products exploit the unique properties of New Zealand made light gauge high strength steel, and will be available to the domestic construction market as well as being exported internationally through Tata Steel’s existing supply chain (which, inter alia, includes Fiji, Singapore, Hong Kong, India, Ghana, Europe and Cuba).

Unlike the earlier development programmes that were conducted in Europe, Tata Steel International awarded the work to HERA due to the long experience possessed by Dr Stephen Hicks in product development and certification activities.

deformation-midspan
Deformation in the mid-span region of the floor deck test specimen at maximum load.

To gain access to overseas markets such as the European Union (EU) and the European Free Trade Area (EFTA), the testing and evaluation of the design properties was conducted according to international harmonized Standards, which will also facilitate CE Marking of the products in the future.

The physical testing of the deck products for both the bare steel and the composite stage were undertaken at the University of Auckland, whose expertise ensured the success of this aspect of the work. A novel approach compared to earlier development programmes that were previously undertaken overseas was followed, in that the theoretical model used in the structural reliability analyses was based on finite element (FE) models.

The benefit of using FE models was that they could accurately account for the effect of small manufacturing tolerances on the structural performance of the profiles, which permitted the design values to be maximized whilst still maintaining the required levels of safety demanded by international Standards.

The benefits of this approach were clearly demonstrated through a 19% saving in steel weight compared to similar products that possess an identical spanning capability, thereby resulting in significant cost savings to the client.

fe-predictions-deformation
FE predictions of the deformation of the floor deck specimen at maximum load including von Mises stress contours (half of test specimen modeled due to symmetry).