Current revision of the fundamental Eurocode for design of civil engineering structures

Vestnik MGSU 9/2018 Volume 13
  • Marková Jana - Klokner Institute, Czech Technical University (CTU), in Prague, 7 Šolínova, Prague 6, 166 08, Czech Republic ssociated Professor; ORCID ID 0000-0002-9674-0718, Klokner Institute, Czech Technical University (CTU), in Prague, 7 Šolínova, Prague 6, 166 08, Czech Republic, 7 Šolínova, Prague 6, 166 08, Czech Republic.
  • Holický Milan - Klokner Institute, Czech Technical University (CTU), in Prague, 7 Šolínova, Prague 6, 166 08, Czech Republic Professor; ORCID ID 0000-0001-5325-6470, Klokner Institute, Czech Technical University (CTU), in Prague, 7 Šolínova, Prague 6, 166 08, Czech Republic, 7 Šolínova, Prague 6, 166 08, Czech Republic.
  • Sýkora Miroslav - Klokner Institute, Czech Technical University (CTU), in Prague, 7 Šolínova, Prague 6, 166 08, Czech Republic Associated Professor; ORCID ID 0000-0001-9346-3204., Klokner Institute, Czech Technical University (CTU), in Prague, 7 Šolínova, Prague 6, 166 08, Czech Republic, 7 Šolínova, Prague 6, 166 08, Czech Republic.

Pages 1036-1042

The present, globally-applicable revision of the fundamental EN 1990 Eurocode for the design of buildings and civil engineering structures is briefly summarised. General requirements are further elaborated with respect to structural resistance, serviceability and durability. In addition, provisions for robustness, sustainability and fire safety are included. An appropriate level of structural reliability should consider the consequences and possible causes of failure, public aversion and costs associated with reducing the risk of failure. However, the choice concerning the reliability level is left to national interpretation. The target reliability indexes are indicated for one-year and 50-year reference period, with no explicit link to the design working life being provided in the final draft of prEN 1990. It is proposed that the consequences of structural failure be organised into five categories; however, without providing recommendations on the target reliability indices for the lowest and highest consequence class. Supplementary guidance on structural robustness is proposed in prEN 1990, Annex E. A structure should have a sufficient level of robustness that it will not be damaged to an extent disproportional to the original cause. The working life design should be considered for time-dependent performance of the structures. Ultimate and serviceability limit states should be verified for all relevant design situations. Apart from the commonly-used partial factor method, which comprises a basic method for structural verification, additional guidance is also given for application of non-linear methods. The partial factors have been newly-calibrated with the aim of achieving a more balanced reliability level for structures from different materials and loading effects.

DOI: 10.22227/1997-0935.2018.9.1036-1042

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IMPLEMENTATION AND APPLICATION OF EUROCODES

Vestnik MGSU 10/2012
  • Holický Milan - Klokner Institute, Czech Technical University in Prague (CTU) Doctor of Philosophy, Professor, Deputy Director, Klokner Institute, Czech Technical University in Prague (CTU), Solinova 7, 166 08, Prague 6, Czech Republic; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .
  • Markova Jana - Czech Technical University in Prague (CTU) Assoc. Prof., researcher, Klokner Institute, +420 2 2435 3501, Czech Technical University in Prague (CTU), Solinova 7, 166 08 Prague 6, Czech Republic; This e-mail address is being protected from spambots. You need JavaScript enabled to view it .

Pages 11 - 19

Technical and editorial problems may be encountered during the implementation of Eurocodes into the systems of national standards. The main technical problems to be solved include specification of the target reliability levels of different types of construction works, definition of characteristic values, partial and combination factors and load combination rules for structures and geotechnical design. It is expected that in the next generation of Eurocodes further harmonisation and reduction of NDPs on the basis of technical assessment will be provided.
Present generation of Eurocodes encompass a suite of 58 Parts which represents a great achievement in European harmonization of structural codes. The key role in the design of new and existing structures represents the concept of reliability differentiation of construction works and the selection of target reliability level. Recommended target reliability level, expressed commonly by reliability index b = Φ-1(), where Φ denotes the standardized normal distribution function and the failure probability, are provided in several documents.
Load combination rules for verification of geotechnical design (ULS of type GEO) give three alternative approaches leading in some cases to considerably different results. For example, resulting dimensions of common footing may have differences about 20 to 40 %.
Other technical problems of implementation include lack of guidance for application of different design situations. For example a structure under fire should be verified according to the accidental design situation for which alternative combination factors are indicated in EN 1990. During subsequent repair the structure should comply with the requirements for the transient design situation, for which, up to now, there are no explicit rules for existing structures provided by Eurocodes.
Another problem is a unified definition of the characteristic values for variable actions, particularly for imposed and climatic actions, when 0.98 fractile for time dependent components should be supplemented by probabilistic specification of resulting action effect (for example, for imposed load and wind).
System of Eurocodes constitutes a great achievement in harmonization of European standards for structural design. In national implementation, it is strongly recommended to specify a unique (unambiguous) variant chosen from recommended options. Terminology and translation should be adapted to the sense of the original English version. Other manner of translations may be confusing or misleading.

DOI: 10.22227/1997-0935.2012.10.11 - 19

References
  1. Probabilistic model code. JCSS. 2008. http://www.jcss.byg.dtu.dk/publications.
  2. ISO 2394. General principles on reliability for structures. ISO. Geneva, 1998.
  3. ISO 13824. General principles on reliability for structures. ISO. Geneva, 1998.
  4. Guideline on Risk Assessment. Principles, System Representation & Risk Criteria. JCSS. 2008. http://www.jcss.byg.dtu.dk/publications.
  5. Gulvanessian H., Calgaro J.-A., Holick? M. Designer’s Guide to EN 1990, Eurocode: Basis of Structural Design. Thomas Telford, London, 2002, 192 pp. (Russian translation published by MGSU, Moscow, 2011).
  6. Holick? M. Reliability analysis for structural design. ISBN 978-1-920338-11-4, SUN MeDIA, Stellenbosch, South Africa, 2009, 199 p.
  7. Holick? M., Markova J. Calibration of partial factors for design of concrete structures. ICASP 2011, Curych.
  8. EN 1990. Basis of structural design. CEN, 2002.
  9. EN 1991-1-1. Action on structures – Part 1-1 General actions — densities, self-weight, imposed load for buildings. CEN, 2002.
  10. EN 1991-1-4 Action on structures – Part 1-4 Wind actions. CEN, 2005.
  11. EN 1991-1-7 Action on structures – Part 1-7 Accidental actions from impact and explosion. CEN, 2006.
  12. Calgaro J.A. The Eurocodes and Construction Industry. Medium-Term Strategy. 2008—2013. CEN/TC 250, 2010.
  13. Construction Norms and Rules 2.01.07—85. Collection of Rules: Loads and Actions. Construction Rules 20.13330.2011.

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