Italy, Greece, Turkey, Cyprus and Iceland are the countries with the greatest seismic risk in Europe, according to the Swiss Seismological Service, as they are areas with high tectonic activity. This activity could increase by 10% in the next 50 years.
Anchors and fixings play a fundamental role in structural and non-structural installations, and even more so when seismic movement occurs. That is why, since 2013 the use of anchors and fixings has been subjected to a regularisation and standardisation through Eurocode 2, part 4, annex C (EN 1992-4 standard), and thus to a testing process that includes all the technical data required for designing structures with seismic stress.
Suitability for seismic loads is classified into:
Whether or not these are mandatory depends on the regulations of each country.
In Spain, it is currently mandatory to use approved products with anchor seismic categories C1 and C2 in established areas as per the following seismic danger map for residential areas and all ground types (In the light orange zone, the seismic category to be used depends on the ground type).
Non-structural systems are those whose failure does not put at risk the general stability of the construction works, for instance: electrical installations, piping and ventilation and heating systems.
The characteristic of being “redundant” refers to applications with multiple fixings where in the event that one of them fails or is excessively displaced, the load will be distributed to neighbouring fixings without significantly violating the resistance and service requirements of the system.
First of all, it is necessary to verify with the official bodies of the country where the installation will be carried out if there are any requirements in relation to the class of the building or type of application. The following table shows a choice of seismic performance according to the degree of seismic action and the Class of importance of buildings according to EN 1998-1: 2011, 4.2.5.
Seismic levela | Level of importance as per: EN 1998-1, 4.2.5 | |||
---|---|---|---|---|
Class ag Sº | I | II | III | IV |
Very lowb ag S ≥ 0,05 g | No additional requirement | |||
Lowb 0,05 g < ag S ≥ 0,10 g | C1 | C1d or C2o | C2 | |
> Low tog S ≥ 0,10 g | C1 | C2 |
Area | SEISMICITY | Building importance level category | |||
---|---|---|---|---|---|
I | II | III | IV | ||
1 | Very weak | No seismic requirements | |||
2 | Weak | C1 non-structural C2 structural |
|||
3 | Moderate | C2 | |||
4 | Medium | ||||
5 | Strong |
Building importance levels:
The process is similar to that of obtaining an ETA. A prerequisite is that the anchor must first be approved for cracked concrete (options 1 to 6 of the EAD).
The specific tests for seismic performance depend on the category of C1 or C2, and are established in the corresponding EAD. They include tests with large cracks and cyclical loads.
The seismic performance of an anchor is indicated in the corresponding ETA. In the case of INDEX®, in addition to the corresponding ETA seal, we include a Seismic seal which identifies the seismic approval category (C1, C2 or C1 and C2).