Adopting the Eurocodes:

Why, When and How?

Professor David A Nethercot

Tan Swan BEng Endowed Professor

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TSB Public Lecture Wednesday, 6th August 2014

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IStructE View of Structural Eurocodes

• The Structural Eurocodes are the most wide-ranging change to codification of Structural Design ever experienced in the UK.

• They are in many ways the most technically advanced suite of structural design codes anywhere in the world.

Structural Eurocodes

• 1973, UK (Denmark and Ireland) sign the “Treaty of Rome

• Removal of barriers to free movement of goods and services within the EEC

• National Standards for construction works seen as one such “barrier”

• Elimination of National Standards for Structural Engineering

• Work commenced on common standards for use within all member countries

• Cover all aspects of structural design and execution

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Current Position

• 40 years on

• 10 Structural Eurocodes

• Cover all materials, including Geotechnics, as well as Basis of Design, Loading and Seismic

• 58 parts

• Thousands of pages

• Now implemented throughout Europe

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The Structural Eurocodes - Scope

• The structural Eurocodes are – EN 1990 Basis of structural design

– EN 1991 Actions on structures

– EN 1992 Design of concrete structures

– EN 1993 Design of steel structures

– EN 1994 Design of composite steel and concrete structures

– EN 1995 Design of timber structures

– EN 1996 Design of masonry structures

– EN 1997 Geotechnical design

– EN 1998 Design of structures for earthquake resistance

– EN 1999 Design of aluminium structures

Development

• European Commission – Project teams (1975)

• Considerable variability in scope and style

• CEN (European body responsible for Standardisation)

• CEN TC 250 – overall responsibility (1989)

• New Project teams ENV and EN

• Input from National Standards Organisations

• Limited use in practice of ENVs

• National Application Documents

• Gulliotine

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Particular Features

No duplication of material

• Efficient in theory

• Inconvenient to refer to different sections when conducting a single task

• Even more so if moving across several documents e.g. composite bridge

• Navigation through and between documents

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Axis System

Follows that used by computer software xx - along the member yy - axis of the cross-section zz - axis for the cross section

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Language

• Equivalent meaning in several European languages

• “Actions” and “Loads”

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Arrangement

• Similar sequence in documents

• Grouped by task not by need i.e. shear checks not beam design

• Scope to repackage

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Code not “Textbook”

• English speaking guidance, procedure

• Mainland Europe principles

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What does adoption mean for countries outside the EU?

• Switzerland, Norway... • Malaysia, Hong Kong, Singapore... • USA, China, Australia...

Role of Structural Codes

• Codes don’t provide imagination, concepts and flair

• Codes don’t replace personnel experience, knowledge and understanding

• Therefore use them wisely and creatively, not in an unthinking and prescriptive fashion

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• Assist in ensuring the integrity of structural designs and thence the production of safe structures

• Modus Operandus varies e.g. Italy vs UK

• Invoked in contracts, insurance etc

• Questionable value of “designed according to the Code”

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1975 Commission of the European Community

• Common design criteria

• Common understanding

• Facilitate exchanges

• Facilitate marketing

• Common basis for R & D

• Increase competitiveness

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BS0 A Standard for Standards – 6 aims of Standardisation

i. To simplify the growing variety of products and procedures

ii. To improve communications

iii. To promote overall economy

iv. To ensure safety

v. To protect consumer and community interests

vi. To eliminate trade barriers

Obvious potential for conflict

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Dr Flint – chairman Part 3 of BS5400 writing in 1980

• “Designers have different priorities. Many plead for simplicity in a Code both for speed of application and to enable it to be used by Engineers with limited experience. Some expect rules to be both simple and all embracing. Others expect that they should refer to fundamental knowledge when designing major bridges and want freedom for experienced designers to work beyond the scope of a Code. Those competing for worldwide markets require the Code to produce the “most economical” bridges. Simplicity of design rules and economy in the material content of a bridge are incompatible for other than simple structures”.

• “Researchers desire a code to be technically perfect and comprehensive, making use of the most recent research results.”

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Use of Codes

• Part of the portfolio of assistance available to the structural designer:

• Manufacturers literature

• Design guides

• Software

• Textbooks

• Worked examples

• Substantial infrastructure supporting the use of a (major) code

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Design Guides Textbooks Software Manuals Worked Examples

Codes

Designer

Product Standards Manufacturers Literature

Education, Experience and Understanding

Amplify

Simplify

Supplement

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• “The onset of new or revised regulations invariably

heralds a trying period of the unfortunate people who have to work such regulations. This applies both to those who have to comply with, and those who have to administer, such regulations”.

Transition

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Transition Costs

• £2500M - UK Steel Construction Industry

• £200M - Total Design Costs

• £100M - Fraction directly Code related

• £10M - Efficiency loss

• ? - Consequence of misapplication failure

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Item £

Cost of purchasing 1 set of Structural Eurocodes including National Annexes (estimate) 2,750

Cost of buying guidance documents (assumed) 1,000

Cost of updating software (assumed) 20,000

Attendance at technical seminars (assume 3 days per person)

Cost of seminars (assume £150 net each seminar) = 16 x 3 £150

Cost of attendance = 16 x 3 x 7.5 x £50

7,200

18,000

Familiarisation with codes in the office (assume 12 man-days for each person) = 16 x 12 x 7.5 x

£50

72,500

Alterations to standard ‘in house’ specification documents (allow 14 documents at an average of 1

man-day each ) = 14 x 7.5 x £50

5,250

Loss of productivity during first year of change (assume average annual billing (productive time) =

1600 and 10% loss of productivity) = 1600 x 16 x 0.1 x £50

128,000

Total 254,700

Note: The cost rate is based on costs averaged over all staff, from junior technician to

director/partner and is not intended to include an element of profit.

Why adopt

• Comprehensive and up to date coverage

• Widespread adoption throughout Europe – and possibly beyond

• Supporting infrastructure will migrate to Eurocode basis

• Clients and Insurers likely to specify

• Basis for Technical Education (in Europe)

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Supporting Infrastructure

• General information on available resources

• Simplified and/or more limited presentations of the Code Rules

• Explanatory texts aimed at experienced Engineers unfamiliar with the particular provisions of the Codes.

• Supplementary material expanding on Code provisions and/or making their use easier

• Text-books giving background and explanation of how the provisions should be used

• Illustrative worked examples

• Computer software

• Short courses for practicing Engineers

• Teaching materials aimed at undergraduate students

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Eurocode Expert

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Structural Codes

• IStructE Manuals

• Thomas Telford’s “Designer’s Guide to…” - 14

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NCCI

Non Contradictory Complimentary Information

• Provides amplification and explanation

• “Fills (some) gaps”

• User friendly

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Appraisal

• Suite of Structural Eurocodes represent a major technical resource

• They are already implemented in virtually all European countries, with substantial interest from outside Europe

• They aren’t perfect; to be used effectively they require the supporting infrastructure to be in place

• Adopting (or adapting and adopting) represents a major task requiring planning and resourcing

• Events are moving quickly; the situation is much changed from 5 years ago

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Background to the study

• IStructE approached by ODPM in December 2003

• ‘National Strategy for Eurocodes’ Committee formed

– Chairman Professor David Nethercot, President IStructE

• Work commenced, 1 February 2004

• Report submitted to ODPM, 30 April 2004

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APPRAISAL

• Only a part of the designer’s available material

• Balance – competitive and comprehensive vs ease of use

• Facilitate not restrict – assist and guide vs prevent

• Need to “sell the benefits”

• All estimates of production time will be exceeded

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Conclusion – 1

The Structural Eurocodes are:

• Comprehensive in their coverage

• Written in a consistent style across the different parts

• A reflection of the most up to date knowledge

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Conclusion – 2

The Structural Eurocodes are not:

• Easy to use

• A continuation of the style of earlier National Codes

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• A planned approach

• Realisation that resources will be needed

• Recognition of the importance of supporting material

• Appreciation of the scale of the task

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Conclusion 3

Adopting the Structural Eurocodes requires: