Eurocodes

1. The beginnings

Article 100 of the Treaties of Rome from 1957 and the "Single European Act (SEA)" from 1987 obligated the member states to take measures to make the European single market a reality. One goal was to remove technical barriers to trade resulting from differing national specifications and usages in the construction sector; another was to harmonise technical tenders. Over the course of fifteen years and with the help of a steering committee made up of representatives from the member states, the EU Commission was in charge of the development of the Eurocodes.

2. The first generation

In 1990, the EU Commission, the member states of the EU and EFTA decided, on the basis of an agreement between the EU Commission and the European Committee for Standardization (CEN), to delegate the preparation and publication of Eurocodes to CEN in the form of mandates in order to given them the status of European standards. This links Eurocodes to the specifications of all the Council's directives and/or the Commission's decisions that are related to European standards.

The technical committee CEN/TC 250 "Structural Eurocodes", the secretariat of which is held by the British Standards Institution (BSI), was established to produce the Eurocodes. A separate sub-committee was set up for each of the ten sub-areas (e.g. CEN/TC 250/SC 2 "Design of concrete structures"). The first generation of Eurocodes was published in 62 parts from the mid-1990s onwards as European prestandards (ENV), known in Austria as ÖNORM ENV, in order to gain experience with the content, some of which was completely new. Use of these ENV was recommended.

3. How prestandards (ENV) became standards (EN)

Building on the practical experiences gained with the ENVs, at the end of the 1990s, work began again in CEN/TC 250 to convert, i.e. revise, the Eurocodes. The result of this work is Eurocodes, which are published as European standards (EN), known in Austria as ÖNORM EN.

The first parts appeared in 2003. By 2008, all 58 parts were in place. Use of these ENs is binding.

Once all the Eurocodes had been converted into national standards, a transitional period lasting several years started. During this time, national standards could still exist even if their content conflicted with that of the Eurocodes.

During the transitional period (period of coexistence), calculations could be undertaken in line with both the existing ÖNORM standards B 4xxx and the PRESTANDARDS ÖNORM ENV 199x or later ÖNORM standards EN 199x and the related national annexes ÖNORM standards B 199x. The contents of the PRESTANDARD ÖNORM ENV 199x were not the same as the same number of ÖNORM EN 199x in all areas.

Roadmap for the introduction of the Eurocodes (pdf - 150kb)

The transitional period ended in Austria at the end of June 2009. From this point on, conflicting national standards had to be revised or repealed and/or new standards for the introduction of Eurocodes in Austria had to be produced.

However, additional rules or rules supplementary to the current Eurocode may be definitive for assessing the load capacity of existing structures during repair or modification work of if there is an intentional change of use. ÖNORM B 4008-1 applies to assessing the load capacity of existing buildings that were constructed before the Eurocodes were introduced and ÖNORM B 4008-2 applies to bridge constructions.

Documents for assessing the load capacity of existing structures

ÖNORM B 4008-1      Assessment of load capacity of existing structures - Part 1: Building construction

ÖNORM B 4008-2      Assessment of load capacity of existing structures – Part 2: Bridge construction

3.1. Status and validity of the Eurocodes

The member states of the EU and EFTA see the Eurocodes as reference documents for the following purposes:

• As a means of demonstrating that buildings and civil engineering works comply with the essential requirements of Directive 89/106/EEC (Construction Products Directive), in particular with the essential requirement no. 1 "Mechanical resistance and stability" and the essential requirement no. 2 "Safety in case of fire";
• As the basis for specifying contracts to produce structures and the engineering work this requires;
• As a framework condition for producing harmonised, technical specifications for construction products (ENs and ETAs).

Since they refer to structures, the Eurocodes are linked directly to the interpretative documents, to which reference is made in Article 12 of the Construction Products Directive, if they are of a different type to the harmonised product standards.

The technical aspects resulting from the Eurocodes must therefore be noted by the Technical Committees at CEN and the working groups at EOTA which work on product standards so that these standards are fully compatible with the Eurocodes.

The Eurocodes provide rules for the design of complete structures and construction components, which are suited to daily use. They go into the details of traditional construction methods and aspects of innovative applications, but do not provide complete rules for unusual construction solutions and draft conditions, for which specialist input may be required.

4. Introducing Eurocodes in Austria

"Guidance Paper L" was produced by the "Eurocode National Correspondents (ENC)" group as a guideline for introducing Eurocodes. The ENC group was set up by the European Commission and comprises national government officials.

4.1. Guidance papers

Guidance papers have been and are written to better understand matters resulting from how the Construction Products Directive is interpreted.

Structure of the guidance papers (G. P.)
Preface General introduction to the guidance papers

Discover more on the website of the European Commission.

4.2. National implementation

National definitions - National Annex

In order to accommodate the different safety levels which prevail in Europe, Eurocodes allow nationally determined parameters (e.g. values, calculation methods, classes) to be selected. These take account of national circumstances. The National Annexes are currently being prepared in the corresponding committees.

The definitions that may apply at national level for an ÖNORM EN 199x-x-x can be found in a National Annex. This is a national standard, designated ÖNORM B 199x-x-x, and should be applied together with the European standard.

The connection between the two standards is established via a National Preface in the ÖNORM EN 199-x-x-x.

Content of the National Annex

• The key content of a National Annex is the nationally determined parameters (NDP), e.g. partial safety factors.
• Explanations: Should the committee responsible believe that general application of content is not recommended, for reasons of safety for example, a restricted area of application is proposed. Any lack of clarity resulting from the translation into German from English is resolved here.
• Further application guides: If a particular topic is not dealt with in an EN 199x-x-x, appropriate definitions, which do not conflict with the Eurocode, are provided in this section.

4.3. Eurocodes today

Implementierung von Eurocodes in Österreich - Stand März 2016 (PDF, 184 KB)

5. Significance of Eurocodes - standards and legislation

As a member of the European Committee for Standardization (CEN), Austria is obliged to adopt European standards (EN) in national regulations. European standards are also used to implement the directives of the European Commission. These directives must be converted into national law by means of appropriate statutory provisions.

This means that laws are specified in detail with the aid of technical standards.

5.1. Key directives for the construction sector

The marketing of construction products in the European single market was first regulated throughout Europe by the Construction Products Directive (CPD) published in 1989.

Construction Products Directive

Directive 89/106/EEC of the Council of 21 December 1988 on the approximation of laws, regulations and administrative provisions of the Member States relating to construction products Gazette no. L 040 of 11/02/1989, p. 012 - 026

Sector Procurement Directive

Directive 2004/17/EC of the European Parliament and of the Council of 31 March 2004 coordinating the procurement procedures of entities operating in the water, energy, transport and postal services sectors Gazette no. L 134 of 30/04/2004, p. 001 - 113

Procurement Directive

Directive 2004/18/EC of the European Parliament and of the Council of 31 March 2004 on the coordination of procedures for the award of public works contracts, public supply contracts and public service contracts
Gazette no. L 134 of 30/04/2004, p. 114 - 240

5.2. Overview of EU directives

• New Approach Standardisation in the Internal Market
• NANDO (New Approach Notified and Designated Organisations)
   

6. Technical changes resulting from Eurocodes

The most significant change relates to the introduction of the semi-probabilistic safety concept.

The global safety factor

To date, structural components have been calculated and/or sized such that a component is considered "safe" as soon as the resistance (R) to actions (A) is achieved with a level of certainty (η).

R > η · E

In this case, the value η is known as the global safety factor because it is only applied as the multiplicator for actions once the necessary calculations have been undertaken. One single value is therefore used to take account of naturally pre-existing uncertainties (dimensional inaccuracies, component tolerances, approach taken to calculate actions).

The semi-probabilistic safety factor

Using the semi-probabilistic safety factor provides a more detailed calculation process. The spread of influencing factors is immediately "brought to account" in the respective stage of the calculation. This is done with the aid of what are known as partial safety factors γ.

If the properties of an influencing variable are known in detail, e.g. the density of water, the partial safety factor γ is close or equal to 1. To take account of a dynamic action, the progression and absolute variables of which can only be estimated, the partial safety factor γ could equal 2.5.

By

• increasing the nominal value (characteristic value) of an action (partial safety factor γ of more than 1) and/or
• reducing the nominal value (characteristic value) of a component's resistance (partial safety factor γ of less than 1)

you get what are known as draft or design values (Rd or Ed).

Once the necessary calculations have been performed, you finally have to prove that

Rd > Ed.

A component or even a building project is then considered to be adequately sized.

7. Specialist fields and implementation

7.1. An overview of Eurocodes

The Eurocodes are split into the following main groups:

7.1.1. EN 1990 - Basis of structural design

EN 1990 establishes principles and requirements for the safety, serviceability and durability of structures. It describes the basis for their design and verification and provides guidelines for related aspects of structural reliability. It is based on the concept of design according to limit states with partial safety factors.

This document applies in conjunction with EN 1991 to EN 1999 for the structural design of buildings and civil engineering works, including geotechnical aspects, structural fire design, situations involving earthquakes, execution and temporary structures. For the design of special construction works (nuclear installations, dams, etc.), other provisions than those in EN 1990 to EN 1999 might be necessary.

EN 1990 is applicable for the design of structures where other materials or other actions outside the scope of EN 1991 to EN 1999 are involved. With regards to matters of reliability associated with the safety, serviceability and durability of structures, it also provides information, as a reference document, for other Technical Committees at CEN working on structural matters.

This ÖNORM can also be used to assess the load capacity of existing structures, during repair or modification work of if there is an intentional change of use.

EN 1990 is to be applied together with the national annex ÖNORM B 1990-1, which contains national specifications for Annex A1 (building construction). Annex A1 specifies recommended partial safety factors for actions in building construction. EN 1990/A1 with Annex A2 is valid for bridges. The corresponding national annex is called ÖNORM B 1990-2.

The numerical values for partial safety factors and other reliability parameters are recommendations for achieving an acceptable level of reliability. Appropriate expertise and quality assurance are assumed.

Current documents

• ÖNORM EN 1990: Eurocode - Basis of structural design
• ÖNORM EN 1990/A1: Basis of structural design - Amendment 1: Application for bridges

National Annex

• ÖNORM B 1990-1: Eurocode - Basis of structural design - Part 1: Building construction
• ÖNORM B 1990-2: Eurocode - Basis of structural design - Part 2: Bridge construction

7.1.2. EN 1991 - Actions on structures

The following standards are concerned with the general actions on structures; special actions on civil works (e.g. cranes and machinery) are also regulated:

7.1.3. EN 1992 - Design of concrete structures

The following standards are concerned with the sizing and design of concrete and prestressed concrete structures:

Eurocode 2 applies to the design of buildings and civil engineering works made from concrete, reinforced concrete and prestressed concrete. Eurocode 2 corresponds to the principles and requirements for the load capacity and serviceability of structures, as well as the principles for the design and verification of said structures, which are contained in EN 1990 "Basis of structural design".

EN 13670 must be applied for the execution of buildings and civil engineering works made from concrete, reinforced concrete and prestressed concrete in compliance with the Eurocodes.

Eurocode 2 is only concerned with the load capacity, serviceability, durability and fire resistance requirements of structures made from concrete, reinforced concrete and prestressed concrete.

Eurocode 2 is intended to be applied in conjunction with the following regulations:

• EN 1990 Basis of structural design
• EN 1991 Actions on structures
• EN 13670 Execution of concrete structures
• EN 1997 Geotechnical design
• EN 1998 Design of structures for earthquake resistance
• ENs, ETAGs and ETAs for construction products used for concrete, reinforced concrete and prestressed concrete structures

7.1.4. EN 1993 - Design of steel structures

The following standards are concerned with the design of steel structures:

Eurocode 3 applies to the design of steel structures. Eurocode 3 corresponds to the principles and requirements for the load capacity and serviceability of structures, as well as the principles for the design and verification of said structures, which are contained in EN 1990 – Basis of structural design.

EN 1090-2 should be used for the execution of steel structures in compliance with the Eurocode. EN 1090-1 should be applied for the conformity assessment.

Eurocode 3 is only concerned with the load capacity, serviceability, durability and fire resistance requirements of structures made from steel. Other requirements, e.g. concerning thermal or sound insulation, are not considered.

Eurocode 3 applies in conjunction with the following regulations:

• EN 1990 Basis of structural design,
• EN 1991 Actions on structures,
• ENs, ETAGs and ETAs for construction products used for steel structures,
• EN 1090-1 Execution of steel structures and aluminium structures - Part 1: Requirements for conformity assessment of structural components,
• EN 1090-2 Execution of steel structures and aluminium structures - Part 2: Technical requirements for the execution of steel structures and
• EN 1992 to EN 1999, in so far as reference is made to steel structures or steel construction components.

EN 1993-2 to EN 1993-6 refer to the basic rules of EN 1993-1, the regulations in EN 1993-2 to EN 1993-6 are supplements to the basic rules in EN 1993-1.

7.1.5. EN 1994 - Design of composite steel and concrete structures

The following standards are concerned with the sizing and design of composite steel and concrete structures:

Eurocode 4 applies to the design of composite steel and concrete structures and components. Eurocode 4 corresponds to the principles and requirements for the load capacity and serviceability of structures as well as the requirements stated in EN 1990 "Basis of structural design" regarding the safety and serviceability of structures.

EN 1090 should be applied for the execution of steel structures in compliance with the Eurocode and EN 13670 should be used for concrete, reinforced concrete and prestressed concrete structures.

Eurocode 4 is only concerned with the load capacity, serviceability, durability and fire resistance requirements of structures made from composite steel and concrete. Other requirements, e.g. concerning thermal or sound insulation, are not considered.

urocode 4 is intended to be applied in conjunction with the following regulations:

• EN 1990 Basis of structural design
• EN 1991 Actions on structures
• ENs, ETAGs and ETAs for construction products used for composite steel and concrete structures
• EN 1090 Execution of steel structures and aluminium structures
• EN 13670 Execution of concrete structures
• EN 1992 Design of concrete structures
• EN 1993 Design of steel structures
• EN 1997 Geotechnical design
• EN 1998 Design of structures for earthquake resistance

7.1.6. EN 1995 - Design of timber structures

The following standards are concerned with the sizing and design of timber structures:

Eurocode 5 applies to the design of buildings and civil engineering works in timber (solid timber, sawn, planed or in pole form, glued laminated timber or other wood-based structural products, e.g. LVL) or wood-based panels jointed together with adhesives or mechanical fasteners. It complies with the principles and requirements for the safety and serviceability of structures and the basis of design and verification given in EN 1990.

There is not currently a special execution standard for buildings and civil engineering works in timber.

Eurocode 5 is only concerned with mechanical resistance, serviceability, durability and fire resistance requirements of timber structures. Other requirements, e.g. concerning thermal or sound insulation, are not considered.

Eurocode 5 is intended to be used in conjunction with:

• EN 1990:2002 Basis of structural design,
• EN 1991 Actions on structures,
• ENs for construction products for timber structures,
• EN 1998 Design of structures for earthquake resistance when buildings are in seismic regions.

7.1.7. EN 1996 - Design of masonry structures

Eurocode 6 "Design of masonry structures" includes the following four standards:

Eurocode 6 applies to the design of buildings and other civil engineering works, or parts thereof, in unreinforced, reinforced, prestressed and confined masonry.

There is not currently a special execution standard for buildings and civil engineering works made from masonry.

It is only concerned with the load capacity, serviceability and durability requirements of structures. Other requirements, e.g concerning thermal or sound insulation, are not considered.

The execution is covered to the extent that is necessary to indicate the quality of the construction materials and products that should be used and the standard of workmanship on site needed to comply with the assumptions made in the design rules.

Eurocode 6 does not deal with calculations and sizing for structures at risk of earthquakes. Definitions for corresponding requirements can be found in Eurocode 8 "Design of structures for earthquake resistance"; this is a supplement to Eurocode 6 and is in line with it.

The numerical values for actions on buildings and civil engineering works needed for the design are not stated in Eurocode 6. They can be found in Eurocode 1 "Basis of design and actions on structures".

7.1.8. EN 1997 - Geotechnical design

Eurocode 7 comprises two parts:

Eurocode 7 deals with the geotechnical aspects and strength, stability, serviceability and durability requirements of structures.

Eurocode 7 is intended to be applied in conjunction with EN 1990.

The numerical values to be applied for actions when planning buildings and civil engineering works can be found in EN 1991. Actions originating from the ground, such as earth thrusts, must be determined according to the rules stated in EN 1997-1.

The requirements for executing and assessing field and laboratory tests are stated in EN 1997-2.

Other European standards are intended for matters relating to quality assurance and execution. Reference is made to these in the corresponding sections. Execution is covered in Eurocode 7 to the extent that this is necessary to meet the conditions required in the design rules.

EN 1998 contains the principles for seismic measurements.

Normung im Bereich Geotechnik - Normungsgremien (pdf, 50KB)

7.1.9. EN 1998 - Design of structures for earthquake resistance

Eurocode 8 comprises the following standards:

Eurocode 8 applies to the design of buildings and civil engineering works in seismic regions. The aim is to ensure that in the event of earthquakes human lives are protected, damage is limited and structures important for civil protection remain operational.

he random nature of the seismic events and the limited resources available to counter their effects are such as to make the attainment of these goals only partially possible and only measurable in probabilistic terms. The extent of the protection that can be provided to different categories of buildings, which is only measurable in probabilistic terms, is a matter of optimal allocation of resources and is therefore expected to vary from country to country, depending on the relative importance of the seismic risk with respect to risks of other origin and on the global economic resources. Special structures, such as nuclear power plants, offshore structures and large dams, are beyond the scope of EN 1998.

EN 1998 contains only those provisions that, in addition to the provisions of the other relevant EN Eurocodes, must be observed for the design of structures in seismic regions.

7.1.10. EN 1999 - Design of aluminium structures

Eurocode 9 "Design of aluminium structures" comprises the following standards:

EN 1999 applies to the design of buildings and other civil engineering and structural works in aluminium. It covers the principles and requirements for the safety and serviceability of structures, the basis of their design and verification that are given in EN 1990 "Basis of structural design".

>EN 1090-3 should be used for the execution of aluminium structures in compliance with the Eurocode.

Eurocode 9 is only concerned with the load bearing, serviceability, durability and fire resistance requirements of aluminium structures. Other requirements, e.g. concerning thermal or sound insulation, are not considered.

EN 1999 should be applied in conjunction with:

• EN 1990 Basis of structural design,
• EN 1991 Actions on structures,
• ENs, ETAGs and ETAs for construction products used for aluminium structures,
• EN 1090-3 Execution of steel structures and aluminium structures - Part 3: Technical requirements for aluminium structures
• EN 1992 to EN 1998 if reference is made to aluminium structures or aluminium components.