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Harmonization of NDPs

In all 59 parts of the Eurocodes there are 1 573 Nationally Determined Parameters (NDPs). In a number of cases, an NDP cannot be represented by a single numerical value. In fact, many NDPs take the form of tables, graphs, acceptance of the recommended procedure, choice of calculation approach among given alternatives, introduction of a new procedure, etc.

Types of NDPs
TypeType DescriptionNumber%
1Values of parameters39726.3
2Reference to some set of values – tables 16911.2
3Acceptance of the recommended procedure, choice of calculation approach, when alternatives are given, or introduction of a new procedure50233.3
4Country specific data18 1.2
5National charts or tables1 0.1
6Diagrams15 1.0
7References to non-contradictory complementary information 23 1.5
8Decision on the application of informative Annexes24916.5
9Provision of further, more detailed information1026.8
10Reference to information included in an informative annex 30 2.0

Among the material Eurocodes, EN 1992: Design of concrete structures and EN 1993: Design of steel structures include the highest amount of NDPs. The objective of further harmonisation for these NDPs, e.g. partial factors for material and product properties, is the adoption of the recommended values.

EN 1991: Actions on structures contains a big number of NDPs, most of them arising from different geographical, geological and climatic conditions. Further harmonisation will be sought with regard to the methodologies used for the assessment of these NDPS.

The database of NDPs is managed by the Safety and Security of Buildings Unit of the DG Joint Research Centre of the European Commission.

Distribution of NDPs per Type Number and percentage of NDPs per NDP type

Distribution of NDPs in the EN Eurocodes Number and percentage of NDPs per EN Eurocode

By 7 October 2019, the acceptance average of the recommended values (RVs) was 74%. The analysis was based on 69% of the NDPs with RVs that are expected to be uploaded in the Database.

NDPs database: acceptance of recommended values per EN Eurocode as by 07/10/2019 Acceptance of recommended values per EN Eurocode

NDPs database: Acceptance Percentage Map of recommended values per country as by 20191007 Acceptance of recommended values per country