Design of connections for use in concrete

The design of the attachments used to transmit the actions to the stamped concrete is regulated by part 4 of Eurocode 2 (EN 1992-4) .

By the spring of 2019 , EN 1992-4 will have to be adopted by member states . From that date, the design of the attacks for use in concrete will be regulated, for the first time, by a standard, and not by technical specifications as occurred in the past . This is an important step for the sector.

Finally, a single document for the design of attacks for various actions
The new standard summarizes in a single document the design of various connection systems for different actions. This represents a novelty for the sector, since in the past the design of the attacks was described in various documents (see Figure 1).

EN 1992-4 contains both the rules for the design of pre-installed systems (channel profiles, nail pins), and those for post-installed systems (screws, expansion plugs, …). The document contains the design rules for a wide range of actions: static, almost static, seismic and fatigue . There are also some clauses regarding fire design.

Development of the various guidelines for the design of the connections for use in concrete

Figure 1: Time development of the different guidelines for the design of the connections for use in concrete

EN 1992-4 represents the state of the art for the design of attachments that transmit loads to concrete. The inclusion in the Eurocodes program aligns the level of security of the attacks with the more general level of the structures, with particular reference to concrete structures. Furthermore, it guarantees a uniform design procedure throughout Europe.

From the DAfStb a commentary explaining the EN 1992-4 standard
Following the drafting of a specific part of Eurocode 2, and the consequent attention paid to the design of the attacks to be used in concrete, the German Structural Concrete Committee (DAfStb) decided to draw up a commentary to EN 1992-4. The DAfStb 615 document was prepared with the intention of facilitating the understanding and use of the European standard. In order to spread the use of the commentary, even outside of Germany, the commentary was also written in English.

The first part of the commentary contains the explanation of the text of the standard , notes on the derivation of some rules, as well as additional provisions.

The second part illustrates the technical reports mentioned in the standard . Both parties were drafted by the Technical Sub-committee “Fastening Technology” of the DAfStb applying an approval procedure similar to those used in the standardization committees, or the consensus between all the groups involved.

The third part of the commentary contains the articles written by the members of the “Fastening Technology” Technical Sub-Committee of the DAfStb, and contain further explanations of some specific topics . The contributions derive essentially from the involvement of the authors in the work groups that led to the drafting of EN 1992-4, and concern, in particular, some applications not covered by the standard for which some engineering solutions are also proposed.

Public Works: an innovative concrete helps to halve the time for the restoration of the Carimate bridge

The new bridge of Carimate reopened to traffic this afternoon , along the SP 32 Novedratese, which was irreparably damaged on 18 March following the demolition of the overpass in Via Dei Giovi by an oversized truck.

Ponte di Carimate, the reopening to traffic in record time thanks to an innovative concrete
Contrary to the initial 90-day forecast, the important artery returns to be passable after only one month. After the loading tests this morning, this afternoon the ribbon cutting with the President of the Province of Como, Fiorenzo Bongiasca; the Mayor of Carimate, Roberto Allevi; the Mayor of Novedrate, Serafino Grassi; the Mayor of Arosio, Alessandra Pozzoli; the Deputy Mayor, Alice Galbiati, the Mayor of Lentate sul Seveso, Laura Ferrari, the town councilor of Figino Serenza, Stefano Tomaselli and the Regional Councilor Angelo Orsenigo.

” First of all I thank the inhabitants of Carimate for the patience and the volunteers for the hand they gave us in managing the level crossing – declared the President Bongiasca – but also all the Bodies and companies that for various reasons helped us and allowed us to get to reopen the road in such a short time, without counting the precious contribution of the Local Police and the Traffic Police. Once again I like to underline how knowing how to make a team pay. A special mention goes then to the engineer Bruno Tarantola and to all the Technical Office of the Province of Como, without which today we could not already be here “.

A result obtained thanks to the use of the most urgent procedure, but also to the choice of innovative materials. The Province, in fact, turned to the Italian Institute for Concrete, specialized in research and innovation on building materials. Hence the proposal accepted by the Administration to use a particular concrete that guarantees not only a particular durability and resistance but also the rapid maturation process , such as to end in the space of two days instead of twenty-eight, as happens for a standard product. This concrete – AeternumCal – takes its name from the special additive “Aeternum”, included in this recipe, developed by the Italian Institute for Concrete in collaboration with Tekna Chem.