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  • B. Johansson, R. Maquoi, G. Sedlacek, C. Mller, D. Beg

    Joint Report

    Joint Report

    Prepared under the JRC ECCS cooperation agreement for the evolution of Eurocode 3 (programme of CEN / TC 250)

    Background documents in support to the implementation, harmonization and

    further development of the Eurocodes



    First Edition, October 2007

    EUR 22898 EN - 2007

  • B. Johansson, R. Maquoi, G. Sedlacek, C. Mller, D. Beg

    Joint Report

    Prepared under the JRC ECCS cooperation agreement for the evolution of Eurocode 3 (programme of CEN / TC 250)

    Background documents in support to the implementation, harmonization and

    further development of the Eurocodes



    First Edition, October 2007

    EUR 22898 EN - 2007

  • The mission of the JRC is to provide customer-driven scientific and technical support for the conception, development, implementation and monitoring of EU policies. As a service of the European Commission, the JRC functions as a reference centre of science and technology for the Union. Close to the policy-making process, it serves the common interest of the Member States, while being independent of special interests, whether private or national. European Commission Joint Research Centre

    The European Convention for Constructional Steelwork (ECCS) is the federation of the National Associations of Steelwork industries and covers a worldwide network of Industrial Companies, Universities and Research Institutes.

    Contact information Address: Mies-van-der-Rohe-Strae 1, D-52074 Aachen E-mail: Tel.: +49 241 80 25177 Fax: +49 241 80 22140 Legal Notice Neither the European Commission nor any person acting on behalf of the Commission is responsible for the use which might be made of this publication. A great deal of additional information on the European Union is available on the Internet. It can be accessed through the Europa server

    JRC 38239 EUR 22898 EN ISSN 1018-5593 Luxembourg: Office for Official Publications of the European Communities European Communities, 2007 Reproduction is authorised provided the source is acknowledged Printed in Italy

  • Commentary to EN 1993-1-5 First edition 2007



    Both ECCS and the JRC acknowledge the major contribution of the Coordinator of the works, Prof. Bernt Johansson, Division of Steel Structures, Lule University of Technology, who succeeded in keeping the momentum from the Project Team works in CEN/TC250/SC3 to persuade Project Team members to write this commentary.

    The contribution of the many international experts who have supported the works by their comments and reviews as stated in the introduction is also acknowledged.

  • Commentary to EN 1993-1-5 First edition 2007


  • Commentary to EN 1993-1-5 First edition 2007



    The EN Eurocodes are a series of European standards which provide a common series of methods for calculating the mechanical strength of elements playing a structural role in construction works, i.e.the structural construction products. They make it possible to design construction works, to check their stability and to give the necessary dimensions of the structural construction products.

    They are the result of a long procedure of bringing together and harmonizing the different design traditions in the Member States. In the same time, the Member States keep exclusive competence and responsibility for the levels of safety of works.

    According to the Commission Recommendation of 11 December 2003 on the implementation and use of Eurocodes for construction works and structural construction products, the Member States should take all necessary measures to ensure that structural construction products calculated in accordance with the Eurocodes may be used, and therefore they should refer to the Eurocodes in their national regulations on design.

    The Member States may need using specific parameters in order to take into account specific geographical, geological or climatic conditions as well as specific levels of protection applicable in their territory. The Eurocodes contain thus nationally determined parameters, the so-called NDPs, and provide for each of them a recommended value. However, the Member States may give different values to the NDPs if they consider it necessary to ensure that building and civil engineering works are designed and executed in a way that fulfils the national requirements.

    The so-called background documents on Eurocodes are established and collected to provide technical insight on the way the NDPs have been selected and may possibly be modified at the national level. In particular, they intend to justify:

    The theoretical origin of the technical rules, The code provisions through appropriate test evaluations whenever needed (e.g. EN 1990,

    Annex D), The recommendations for the NDPs, The country decisions on the choice of the NDPs.

    Collecting and providing access to the background documents is essential to the Eurocodes implementation process since they are the main source of support to:

    The Member States, when choosing their NDPs, To the users of the Eurocodes where questions are expected, To provide information for the European Technical Approvals and Unique Verifications, To help reducing the NDPs in the Eurocodes when they result from different design

    cultures and procedures in structural analysis, To allow for a strict application of the Commission Recommendation of 11 December

    2003, To gradually align the safety levels across Member States, To further harmonize the design rules across different materials, To further develop the Eurocodes.

    This joint ECCS-JRC report is part of a series of background documents in support to the implementation of Eurocode 3. It provides background information on the specific issue of plated steel structures addressed in EN 1993-1-5.

    For the design of plated steel structures, the rules for shear lag effects and plate buckling that have been specified in EN 1993-1-5 may look novel for many practitioners who so far have been

  • Commentary to EN 1993-1-5 First edition 2007


    acquainted to traditional national rules. These rules draw their reliability and satisfactory applicability not so much from time-testing, but from systematic evaluations of test results to prove compliance with the European reliability requirements and from a certain amount of worked examples and more and more emerging successful practical applications.

    This commentary is meant to provide the following: The background of the rules, Their reliability basis, Explanations on how they are meant to be used, Some key examples.

    The European Convention for Constructional Steelwork (ECCS) has initiated the development of this commentary in the frame of the cooperation between the Commission (JRC) and the ECCS for works on the further evolution of the Eurocodes. It is therefore published as a Joint Commission (JRC)-ECCS report.

    Aachen, Delft and Ispra, August 2007

    Gerhard Sedlacek

    Chairman of the ECCS Technical Management Board

    Frans Bijlaard

    Chairman of CEN/TC 250/SC 3

    Michel Gradin, Artur Pinto and Silvia Dimova

    European Laboratory for Structural Assessment, IPSC, JRC

  • Commentary to EN 1993-1-5 First edition 2007


    Content 1 Introduction 1

    1.1 General 1

    1.2 Calibration of the safety level 2

    1.3 References 6

    2 Design of plated members 7 2.1 General 7

    2.2 Effective width models for global analysis 8

    2.3 Plate buckling effects 9

    2.3.1 General 9

    2.3.2 Reduced stress method and effective width approach 10

    2.3.3 Plate buckling verification methods 16

    2.3.4 The general method 17

    2.3.5 The component method 19

    2.4 Serviceability limits 21

    2.4.1 General 21

    2.4.2 Rules to avoid excessive plate breathing 21

    2.4.3 Comparison of SLS and ULS limit state verification 22

    3 Effective width approaches in design 27 3.1 Contributory areas without shear lag effects 27

    3.2 Shear lag effects 30

    3.3 Basic situations 33

    3.4 Conclusions 35

    3.5 Symmetrical and asymmetrical loading 39

    3.6 Effects at the ultimate limit state 39

    4 Plate buckling effects due to direct stresses 41 4.1 Introduction 41

    4.2 General verification procedures 42

    4.3 Approach based on the reduced cross-section concept 45

    4.3.1 General 45

    4.3.2 Plate behaviour 46

    4.3.3 Column behaviour 50

    4.3.4 Interpolation between plate behaviour and column behaviour 54

    4.3.5 Plate buckling check 55

    4.3.6 Validation of plate buckling check procedure 56

    4.4 References 57

  • Commentary to EN 1993-1-5 First edition 2007


    5 Resistance to shear 59 5.1 Introduction 59

    5.2 Design shear resistance according to EN 1993-1-5 61

    5.2.1 General 61

    5.2.2 Contribution from the web 63

    5.2.3 Contribution from the flanges 69

    5.2.4 Shear resistance check 71

    5.2.5 Verification of the shear resistance formula 71

    5.3 Conclusions 72

    5.4 References 73

    6 Resistance to transverse loads 74 6.1 Background 74

    6.1.1 Buckling 74

    6.1.2 Yielding 75

    6.1.3 Combined models 76

    6.2 Model for patch loading resistance 78

    6.2.1 Plastic resi