Designing connections in concrete according to the COP and requirements of ETAG 001.
The code of practice covers the roles and responsibilities of everyone involved in the design, supply and installation of products in safety critical situations where post installed anchors are used. Safety Critical Situations are defined in the COP as situations where the failure of such connections would cause risk of human injury or death.
The COP requires that all post installed fixings comply with the requirements of the current Construction Products Directive and the incoming Construction Products Regulations. The best way to insure all SCS comply is to use an anchor with a relevant ETA and design the concrete capacity according to the design models of ETAG 001.
As most practices are now using Eurocodes for design I would draw your attention to section 2.7 of EC2 “Requirements for Fastenings”, this states that “The performance of fasteners should comply with the requirements of a CEN Standard or should be demonstrated by a European Technical Approval
Article 8 in chapter III of the construction products directive defines an ETA as follows:
“European technical approval is a favourable technical approval, it is a favourable technical assessment of the fitness for use of a product for an intended use, based on fulfilment of the essential requirements for building works for which the product is used.
Design models of ETAG 001.
The design models of ETAG 001 are more complicated than the old design checks traditionally carried out with anchor manufacturer’s technical handbooks. The main reason for this is that the new design models calculate the concrete capacity for the anchorage. This means we can now calculate the concrete capacity with regard to concrete splitting, concrete edge failure etc as well as pullout and steel failure of the bolt.
The design models now employ different failure models for steel anchors, bonded anchors and post installed rebar. This gives the engineer the opportunity to design much more realistic resistance values for a variety of bolt arrangements. It also means that all anchor producers are now using a harmonized design approach; this takes away any confusion that may have existed as to how each producer arrived at their design resistance values.
This new design method is an integral part of the COP, the design calculations can be carried out using hand calculations but unless the designer is constantly working with anchor design and therefore totally familiar with the code, it is probably preferable to use design software such as the fischer Compufix 8 program.
The code of practice requires that the designer/specifier refers to a particular product, naming the anchor brand and anchor type in the specification “or equivalent”.
Some readers may feel this contravenes the conditions of part 5 section 15 of S.I. No. 329/2006 — European Communities (Award of Public Authorities' Contracts) Regulations 2006
This is not the case as these articles are considered “exceptional” within the terms and conditions of the regulations. Not naming a product introduces the risk of the user not understanding the design resistance requirements of the product and using a product with an insufficient design resistance.
Other readers understand that they must only use the specified product. This is also not the case as the words “or equivalent” must accompany the reference. Product change is totally acceptable as long as the change is managed and it is demonstrated that the replacement product can resist the prevailing design actions.
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