Eurocodes: Frequently Asked Questions
- Introduction to the Eurocodes
- Eurocodes progress
- Highways Agency role in Eurocodes
- Highways Agency Eurocodes strategy
- Using the Eurocodes for bridge design
- Frequently Asked Questions
- Contact for Queries
- Useful links
What are the Eurocodes?
The Eurocodes are pan-European structural design codes. There are ten Eurocodes in a total of 58 parts covering: basis of design; actions on structures; design of structural elements in concrete, steel, composite steel and concrete, timber, masonry and aluminium; together with geotechnical and seismic design. They cover the design of bridges, buildings, silos, tanks, pipelines, towers, masts and more.
Why develop Eurocodes?
In 1975, the Commission of the European Community decided on an action programme in the field of construction based on Article 95 of the Treaty of Rome. The objective of the programme was the elimination of technical obstacles to trade and the harmonisation of technical specifications. The introduction of Eurocodes will eliminate the technical obstacles to trade that exist because of differing design codes in Europe, and will harmonise technical specifications for public procurement, thus creating a more open marketplace.
The introduction of the Eurocodes should enable access to a marketplace estimated in 2004 at £1.5bn annually, and will allow greater opportunities for harmonised research across the Union, saving a considerable amount of money.
What are the National Annexes?
The Eurocodes allow choice of safety related parameters and certain country-specific data, known collectively as Nationally Determined Parameters (NDPs). Each country can publish its chosen values for the NDPs in a National Annex that will accompany the Eurocode part.
The parameters left open for national choice are, generally: partial safety factors; the chosen design life for structures; country specific data such as snow maps, wind maps, isotherm maps and seismic maps; certain additional information on aspects such as durability; some additional safety-related parameters; and decisions on the status of informative annexes in the Eurocode part. In addition, the National Annex may contain references to non-contradictory complementary information.
The National Annex combined with the national title page and national foreword form the British Standard implementing the European Standard. All UK National Annexes relevant to bridge design have now been published and must be used in conjunction with the Eurocodes.
What are the differences between the Eurocodes and the British Standards? Is there a different design philosophy?
The Eurocodes are limit state codes like the British Standards, although are perhaps a little more explicitly based in reliability theory. Many of the Eurocode rules are based on the same theory as the British Standards, although the Eurocodes embody the most up to date research on many aspects of structural behaviour.
The Eurocode clauses are structured in a slightly different way in that they contain principles that must be satisfied and application rules that offer a way of satisfying the principles. This is intended to stimulate innovation. The Eurocodes are also less prescriptive than the British Standards, with more aspects left open to the designer.
Are the Eurocodes mandatory?
Under the Public Procurement Directive, the Member States must accept designs to the Eurocodes. Eurocodes are the standard technical specification for all public works contracts: where a contract for a public body contains a technical specification this should reference the appropriate European Standards. Accordingly, the Highways Agency has been expressing its requirements in terms of Eurocodes for the design of new highway structures in contracts made after 31 March 2010.
Whilst it will not be mandatory to design to the Eurocodes in the UK, should a designer propose alternative design standards, they will have to demonstrate that the alternative is of 'technical equivalence' to a Eurocode solution. As the British Standards Institution (BSI) will not maintain the withdrawn UK standards, in reality there will be little option but to use the Eurocodes.
(See also answer to the question below on the application of Eurocodes for assessments.)
Are Eurocodes for assessment or just for new design?
The Eurocodes are for the design of new structures. They also cover engineering principles that could be used to form the basis of assessment of structures or structural elements.
The Highways Agency currently has no plan to pursue the use of Eurocodes for assessments, as the current DMRB advice notes and standards are sufficiently comprehensive and versatile to cover the assessment of various highway structures.
The use of Eurocodes for assessments will only be considered acceptable if, in the opinion of the TAA, there is sufficient technical information to aid the assessment; further, that there are advantages in using Eurocodes instead of the existing standards for the assessment situation concerned.
What is the target date for the introduction of Eurocodes to the UK?
All 58 Eurocode parts are now available, and all bridge-related National Annexes are now published. The BIS withdrew all National Standards conflicting with Eurocodes on 31 March 2010, at which point Eurocodes became the main structural design standards in the UK.
When will the Eurocodes be used for bridge design?
The publication of National Annexes required for UK bridge design is now complete.
The Agency has published guidance and requirements for the design of highway structures using Eurocodes in a new Interim Advice Note IAN 124/11 (to be followed by the publication of the implementation standard at a later date).
Since 31 March 2010 when conflicting National Standards were withdrawn, the Agency specifies the design of highway structures on the trunk road network in terms of Eurocodes.
Find out more about the Agency's strategy for the Implementation of Eurocodes.
How will the Eurocodes relate to the DMRB?
The review of the existing DMRB with regard to Eurocodes is ongoing and the Agency is taking the opportunity to rationalise the content with a view to making it consistent with the principles of Eurocodes. There will be fewer, more focussed DMRB parts that contain the additional (non-contradictory) requirements of the Overseeing Organisations. The review so far has shown that some of the DMRB standards may have to be withdrawn, some should be modified to align with the design rules in the Eurocodes, while others could remain unchanged to support the assessment standards.
In addition to the DMRB, the Agency is also working with BSI's bridges committee to prepare non-contradictory complementary information (NCCI) for the design of highway structures as Published Documents.
What are BSI Published Documents?
Published Documents, or PDs, are BSI documents that hold a lower status than a Standard. Some UK specific non-contradictory complementary information (NCCI) for bridges will be published in PDs and this information will be referenced in the National Annexes. Much of the NCCI is likely to be from the current National codes that will be withdrawn, but a wide variety of NCCI from other sources will also be referenced.
The BSI has published a number of PDs relating specifically to the design of bridges. These include background information for the National Annexes, and in some cases residual information from BS 5400 that has been adapted to compliment the Eurocodes, for the following parts of the Eurocodes:
- Actions: BS EN 1991-1-4 (wind actions), BS EN 1991-1-5 (thermal actions), BS EN 1991-1-7 (accident actions) and BS EN 1991-2 (traffic actions)
- Materials: BS EN 1992-1-1 (concrete general), BS EN 1992-2 (concrete bridges), BS EN 1993-1-9 (fatigue in steel), BS EN 1993-1-10 (fracture in steel), BS EN 1993-2 (steel bridges) and BS EN 1994-2 (composite bridges)
- Geotechnics: BS EN 1997-1 (geotechnics general, including additional complementary information on the design of geotechnical aspects for bridge elements such as foundations, earth retaining structures and integral abutments)
- Earthquake design: BS EN 1998 Parts 1, 2, 4, 5 and 6 (earthquake design)
- Bearings design to BS EN 1337
- Execution of steel structures to BS EN 1090-2
For a full publication schedule refer to the BSI website.
How will the Eurocodes affect Technical Approval Procedures?
The role of the TAA is considered essential in ensuring safety and reliability even after Eurocodes are implemented, by ensuring compliance with standards.
The current Technical Approval Procedure is in the process of being amended to accommodate the use of Eurocodes.
Are the Eurocodes as safe as current UK standards?
The Eurocodes are regarded to be safe and reliable and have already been used in Europe on a number of landmark structures.
The Agency is reviewing the Eurocodes with regard to safety. The partial safety factors in the National Annexes are determined by the UK and will ensure a level of reliability compatible with the existing UK standards. This is backed by a number of trial / parallel design studies commissioned by the Agency, which show that Eurocode design was largely comparable with design to British Standards.
Will Eurocode designs cost more to construct?
The numerous studies carried out so far indicate that the Eurocodes will have little or no effect on member sizes and quantities in common design situations. This has been confirmed by the trial / parallel design studies commissioned by the Agency. The less prescriptive approach of the Eurocodes should also allow greater scope for innovation and encourage designers to use advanced analysis techniques which, combined with the more open marketplace and greater competition brought about by the implementation of Eurocodes, should lead to better value for money.
It is worth noting, though, that at least initially the actual design process is expected to be more costly - due to designers having to become familiar with the Eurocodes.
Will there be design guides for the Eurocodes?
Yes. A number of design guides have already been published with industry bodies developing a considerable amount of additional guidance. The Useful links page provides links to websites managed by the steel and the concrete industries where guidance is available.
Will bridges have to be re-assessed to the new Eurocode loading and principles?
No, the assessment programme will not be affected by the changeover to Eurocodes. In addition, there are no plans to strengthen or remediate existing structures to suit Eurocodes.
What is BSI's involvement in the Eurocodes?
BSI holds the secretariat for CEN (European Committee for Standardization) technical committee TC250, responsible for the Eurocodes, and is the lead organisation for Eurocodes in Europe. BSI publishes the Eurocodes as BS EN standards and is the secretariat for the British Committees that oversee British interests in the Eurocodes.
How is the Highways Agency involved?
The Highways Agency has been reviewing and commenting on the Eurocodes insofar as they relate to bridges, influencing the National Annexes relating to the General parts of the Eurocodes, and writing the National Annexes relating to the bridges and other highway structures parts of the Eurocodes. We have provided the National Technical Contacts for the Bridge parts of the Eurocodes and played an active part in the development of the Eurocodes in the early years. We have also played an instrumental role in the preparation of the BSI Published Documents containing NCCI for UK bridge design.
Find out more about the Agency's role in Eurocodes.
With which Authorities is the Agency co-ordinating?
With BSI; Communities and Local Government; BRE, Communities and Local Government's consultant on the Buildings and General Eurocodes; the Department for Business, Innovation and Skills (BIS, formerly BERR/DTI); the Office of Government Commerce (OGC); CSS; Network Rail, and Overseeing Organisations in Scotland, Wales and Northern Ireland.
How is highway loading addressed in the Eurocodes?
Normal highway loading is specified in Eurocode 1 Part 2 and supplemented by provisions in the National Annex. This load model comprises a tandem axle system acting in conjunction with a uniformly distributed load. Abnormal loading is specified in the National Annex to Eurocode 1 Part 2. The Interim Advice Note IAN 124/11 specifies which special vehicle load model is appropriate depending on the type of highway.
Will example bridge designs be carried out?
The Agency has carried out several studies using the Eurocodes to design typical highway bridges to examine their effect on safety, economy, technical approvals, specification and to establish the need for additional guidance.
A series of "Designer's Guidance to Eurocodes" have been published, some of which cover the design of bridges. In addition, it is expected that industry bodies such as the Steel Construction Institute and the Concrete Centre will publish example bridge designs using Eurocodes. Click on the links to their websites on the Useful links page where more information is available.
What is the impact of Eurocodes on HA procurement?
As the use of Eurocodes will be through the DMRB, the impact of their use on the procurement and contract documents should broadly be as for other changes in standards. The only difference will be that during the period of co-existence of the two sets of design codes, design to either will be acceptable - specifically, for all types of contract, involving new highways structures design, made before 31 March 2010, the use of Eurocodes will not be mandatory; however, for all types of contracts, involving new highways structures design, made after 31 March 2010, the use of Eurocodes will be mandatory (unless otherwise agreed by the TAA).
On long term contracts (MACs, DBFOs), made before 31 March 2010, the use of Eurocodes will only be mandatory where the detailed design is programmed to commence after 31 March 2010.
There is an issue of for how long a design to the current National codes (within a long-running design programme) would remain acceptable beyond the codes withdrawal date. This is currently being considered.
How will Eurocodes impact on the modification of highway structures?
The Agency will specify that Eurocodes must be used as the basis for the design of modification works to highway structures. This will include design of strengthening and upgrading works, design of replacement of structural elements and design of replacement of components (relevant European Product Standards to be considered in conjunction with Eurocodes).
How will Eurocodes affect the Specification for Highway Works (SHW)?
The Agency is reviewing the SHW to determine how it will be affected by the Eurocodes and what changes will be required. The SHW will have to reflect the European product standards and in many cases already does so. Additionally, the European Execution Standards contain workmanship and erection specifications that will replace the equivalent requirements when published. These changes will also be incorporated in the amendments to the SHW.
The Agency is focusing its efforts on the review of execution requirements for major construction materials, i.e. steel and concrete. The Agency will be considering requirements for the execution of structures in other materials (e.g. aluminium and timber) in due course.
What is the progress of the European Execution Standards?
EN 1090-2 - Execution of steel structures
EN 1090-2 was published as a BS in December 2008. It specifies requirements for the execution of steel and steel-concrete composite structures designed to BS EN 1993 and BS EN 1994 respectively, in order to ensure adequate levels of mechanical resistance and stability, serviceability and durability.
A Published Document providing recommendations for the execution of steel bridges to BS EN 1090-2 has now been published by BSI. Industry has also prepared a model project specification for the execution of steelwork in bridge structures to BS EN 1090-2. The Highways Agency is in the process of updating the SHW to align with BS EN 1090-2 and the published guidance.
EN 13670 - Execution of concrete structures
EN 13670 was published as a BS in February 2010. It specifies requirements for the execution of concrete structures designed to BS EN 1992 and BS EN 1994, in order to ensure adequate levels of mechanical resistance and stability, serviceability and durability.
The SHW 1700 series and the related Notes for Guidance are in the process of being updated to account for the requirements given in EN 13670.
What is the relationship between the Eurocodes and the European Product Standards?
Product Standards exist for construction products, establishing requirements for performance and other properties so products meet the Essential Requirements of the Construction Products Directive. Eurocodes are codes that are concerned with the design of structures. Eurocodes are generally written on the assumption that structures designed in accordance with the Eurocodes will be constructed from products manufactured in accordance with the product standards. Eurocodes can cross-refer to product standards and may form the basis of design for products.
Are tunnels covered by the Eurocodes?
Yes, Eurocodes cover the design of new structural elements for cut and cover tunnels and other similar buried structures. However, only general requirements are given in Eurocodes for this type of structures and further design guidance will be given in the BSI Published Document PD 6694-1 and other guidance documents.
Who is implementing the Eurocodes for buildings?
Communities and Local Government.
How do the general/buildings parts of the Eurocodes relate to bridges?
For most Eurocodes the general part (Part 1-1) is used for building design. For bridge design, Part 2 is used in conjunction with Part 1-1 where appropriate.
How will Eurocodes be maintained?
Procedures for the care and maintenance of Eurocodes have been developed and this will be supported by the CEN committee structure and the national Standards Bodies. The correction of errors will be handled by issuing corrigenda and it is expected that the Eurocodes will be updated on a five-year cycle.
Will lack of software inhibit the implementation of Eurocodes?
Some software providers have already released software capable of supporting Eurocode designs. A number of other program developers have reached an advanced stage in the development of Eurocodes-aligned software. It is therefore not anticipated that computer software for Eurocode design will be lacking.
Further information can be found on the Eurocodes Expert Software Directory (external website).
How is progress on Eurocodes being communicated?
By periodic briefings in industry publications and at conferences such as one held in 2010 at the Institution of Civil Engineers, and those organised by the industry bodies across the country. Additionally and more importantly, comprehensive information about all aspects of the Eurocodes can be found on the Eurocode Expert website. Progress on the Highways Agency implementation strategy for the Eurocodes is given on this website.
What is the impact on research output?
Research for design codes is likely to be pan-European, so the output from the research will benefit all member states, thus making code-based research more efficient and more widely-beneficial.
Where can I purchase the Eurocodes?
BSI is publishing the Eurocodes in the UK and these can be purchased through them or via various other standards subscription services. All of the Eurocodes are now available for purchase; the final National Annexes are in the process of being published. For the latest publication schedule visit the Eurocodes Progress page.
Is training on use of Eurocodes available?
Several training course providers offer courses on the use of Eurocodes. Many of them provide the delegates with hands-on experience in using the codes.
The Highways Agency does not provide its suppliers and business partners any training on the use of Eurocodes.