New Approaches in Fixing Technology: Approvals Follow Design Guides, Shown by Example of Anchor Channels

Connections between steel and concrete were not yet covered by codes until 2009. A European Technical Specification was published in 06/2009 with the aim to provide design rules for anchorages to concrete. This work of the European committee CEN TC 250, published as prCENTS 1992–4, led to a European Technical Approval (ETA) for anchor channels. Following the technical approach, a fib design guide was developed. This design guide will be published approx. in 2010 and gives design rules for several fixing methods such as dowels, headed studs and also anchor channels. This fib design guide will present the basis for a future international approval for anchor channels. This approval will be issued approximately in 2010/2011. In the present state of the art, technical approvals basing on test results only confirm a defined amount of applications with definite boundary conditions. A building product (here: a fixing construction) can only be used in accordance to these regulations. Diverging from the boundary conditions of the technical approval means using a non licensed product e.g. to infringe the approval. With a design guide which describes the general application of a product, a universal calculation becomes possible without constraints towards boundary conditions. A technical approval then "only" proves the applicability of the design rule and the suitability of the product to this documented state of technique. It should be a clear aim of the holders of approvals to support the efforts obtaining design guides and standards to document the technical state of the art which then can be incorporated into technical approvals. This paper gives an overview of these new methods of calculating the resistance of fixing constructions, in this case: anchor channels. The practicality of these formulas on the products is stated by an adequate approval. The design rules are explained and the experimental results are illustrated.