BSI Standards Publication UK National Annex to Eurocode 3 Design of steel structures Part 1 1 General rules and rules for buildings NA+A1 2014 to BS EN 1993 1 1 2005+A1 2014 NA+A1 2014 to BS EN 1993 1[.]
NA+A1:2014 to BS EN 1993-1-1:2005+A1:2014 BSI Standards Publication UK National Annex to Eurocode 3: Design of steel structures Part 1-1: General rules and rules for buildings NA+A1:2014 to BS EN 1993-1-1:2005+A1:2014 BRITISH STANDARD Publishing and copyright information The BSI copyright notice displayed in this document indicates when the document was last issued © The British Standards Institution 2015 Published by BSI Standards Limited 2015 ISBN 978 580 86667 ICS 91.080.10 The following BSI references relate to the work on this standard: Committee reference CB/203 Draft for comment 15/30301400DC Publication history First published December 2008 Amendments issued since publication Date Text affected 30 June 2015 National amendment A1:2014 See Introduction for details BRITISH STANDARD NA+A1:2014 to BS EN 1993-1-1:2005+A1:2014 Contents Introduction NA.1 Scope NA.2 Nationally Determined Parameters NA.3 Decisions on the status of informative annexes NA.4 References to non-contradictory complementary information Bibliography 10 Tables Table NA.1 – Selection of buckling curve for a cross-section Table NA.2 – Suggested limits for vertical deflections Table NA.3 – Suggested limits for horizontal deflections Table NA.4 – Scope and conditions of application of execution class i NA+A1:2014 to BS EN 1993-1-1:2005+A1:2014 This page deliberately left blank BRITISH STANDARD BRITISH STANDARD NA+A1:2014 to BS EN 1993-1-1:2005+A1:2014 National Annex (informative) to BS EN 1993-1-1:2005, Eurocode 3: Design of steel structures – Part 1-1: General rules and rules for buildings Introduction This National Annex has been prepared by BSI Subcommittee CB/203, Design & execution of steel structures It is to be used in conjunction with BS EN 1993-1-1:2005+A1:2014 NA+A1:2014 to BS EN 1993-1-1:2005+A1:2014 supersedes NA to BS EN 1993-1-1:2005, which is withdrawn The start and finish of text introduced or altered by National Amendment is indicated in the text by tags Minor editorial changes are not tagged NA.1 Scope This National Annex gives: a) the decisions for the National Determined Parameters described in the following subclauses of BS EN 1993-1-1:2005+A1:2014: • • • • • • • • • 2.3.1(1) 3.1(2) 3.2.1(1) 3.2.2(1) 3.2.3(1) 3.2.3(3)B 3.2.4(1)B 5.2.1(3) 5.2.2(8) • • • • • • • • • 5.3.2(3) 5.3.2(11) 5.3.4(3) 6.1(1) 6.1(1)B 6.3.2.2(2) 6.3.2.3(1) 6.3.2.3(2) 6.3.2.4(1)B • • • • • • • • • 6.3.2.4(2)B 6.3.3(5) 6.3.4(1) 7.2.1(1)B 7.2.2(1)B 7.2.3(1)B BB.1.3(3)B C.2.2(3) C.2.2(4) b) Decisions on the status of BS EN 1993-1-1:2005+A1:2014 informative annexes; and c) References to non-contradictory complementary information NA.2 Nationally Determined Parameters NA.2.1 General Decisions for the Nationally Determined Parameters decided in BS EN 1993-1-1:2005+A1:2014 are given in clauses NA.2.2 to NA.2.27 NA.2.2 Actions and environmental influences [BS EN 1993-1-1:2005+A1:2014, 2.3.1(1)] There are no additional regional, climatic or accidental situations to consider NA+A1:2014 to BS EN 1993-1-1:2005+A1:2014 BRITISH STANDARD NA.2.3 Other Steel material and products [BS EN 1993-1-1:2005+A1:2014, 3.1(2)] If other steels are used, due allowance should be made for variations in properties, including ductility and weldability Further information on the ductility requirements for steel is given in BS EN 1993-1-1:2005+A1:2014, 3.2.2(1) Steel castings and forgings may be used for components in bearings, junctions and other similar parts Castings should conform to BS EN 10293 and forgings should conform to BS EN 10250-2 Further guidance on steel castings is given in reference [1] For higher strength steels see BS EN 1993-1-12 NA.2.4 Material properties [BS EN 1993-1-1:2005+A1:2014, 3.2.1(1)] The nominal values of the yield strength fy and the ultimate strength fu for structural steel should be those obtained from the product standard The ultimate strength fu should be taken as the lowest value of the range given for Rm in the product standard Further information on the yield and ultimate strength for structural steel is also given in NA.4 NA.2.5 Ductility requirements [BS EN 1993-1-1:2005+A1:2014, 3.2.2(1)] a) Elastic global analysis The limiting values for the ratio fu/fy, the elongation at failure and the ultimate strain εu for elastic global analysis are given below fu/fy, H 1.10; Elongation at failure not less than 15%; εu H 15εy b) Plastic global analysis Plastic global analysis should not be used for bridges For buildings the limiting values for the ratio fu/fy, the elongation at failure and the ultimate strain εu for plastic global analysis are given below fu/fy H 1.15; Elongation at failure not less than 15%; εu H 20εy NA.2.6 Fracture toughness [BS EN 1993-1-1:2005+A1:2014, 3.2.3(1)] For buildings and other quasi-statically loaded structures the lowest service temperature in the steel should be taken as the lowest air temperature which may be taken as −5°C for internal steelwork and −15°C for external steelwork For bridges the lowest service temperature in the steel should be determined according to the NA to BS EN 1991-1-5 for the bridge location For structures susceptible to fatigue it is recommended that the requirements for bridges should be applied 2 BRITISH STANDARD NA+A1:2014 to BS EN 1993-1-1:2005+A1:2014 In other cases (e.g the internal steelwork in cold stores) the lowest service temperature in the steel should be taken as the lowest air temperature expected to occur within the intended design life of the structure NA.2.7 Toughness properties for members in compression [BS EN 1993-1-1:2005+A1:2014, 3.2.3(3)B] The recommendations given in the NA to BS EN 1993-1-10 should be used NA.2.8 Through-thickness properties [BS EN 1993-1-1:2005+A1:2014, 3.2.4(1)B] The recommendations given in the NA to BS EN 1993‑1‑10 should be used NA.2.9 Effects of deformed geometry of the structure [BS EN 1993‑1‑1:2005+A1:2014, 5.2.1(3)] For plastic analysis of clad structures provided that the stiffening effects of masonry infill wall panels or diaphragms of profiled steel sheeting are not taken into account: αcr H 10 For plastic analysis of portal frames subject to gravity loads only with frame imperfections: αcr H provided the following conditions are satisfied: a) The span, L, does not exceed times the mean height of the columns b) hr satisfies the criterion: (hr/sa)2 + (hr/sb)2 G 0.5 in which sa and sb are the horizontal distances from the apex to the columns NOTE For a symmetrical frame this expression simplifies to hr G 0.25L NA.2.10 Structural stability of frames [BS EN 1993‑1‑1:2005+A1:2014, 5.2.2(8)] This method should only be used for frames that comply with 5.2.2(6) In such cases the sway moments in the beams and beam-to-column connections should be multiplied by kr unless a smaller value is shown to be adequate by analysis kr may be evaluated using the following expression provided that acr H 3.0: kr = 1− α cr NA+A1:2014 to BS EN 1993-1-1:2005+A1:2014 BRITISH STANDARD NA.2.11 Design values of initial local bow imperfection [BS EN 1993‑1‑1:2005+A1:2014, 5.3.2(3)] For elastic analysis of the cross-section, the initial imperfections for an individual section about a particular axis should be back‑calculated from the formula for the buckling curves given in BS EN 1993-1-1:2005+A1:2014, 6.3 using the elastic section modulus For plastic analysis of the cross-section, the initial imperfections for an individual section about a particular axis should be back‑calculated from the formula for the buckling curves given in BS EN 1993-1-1:2005+A1:2014, 6.3 using the full plastic section modulus NA.2.12 Amplitude of imperfections [BS EN 1993‑1‑1:2005+A1:2014, 5.3.2(11)] The method given in BS EN 1993-1-1:2005+A1:2014, 5.3.2(11) should not be used for buildings NA.2.13 Imperfections for lateral-torsional bucking in bending [BS EN 1993‑1‑1:2005+A1:2014, 5.3.4(3)] The value of k should be taken as 1.0 NA.2.14 Partial factors for structures not covered by BS EN 1993 Part to Part [BS EN 1993‑1‑1:2005+A1:2014, 6.1(1)] For structures not covered by BS EN 1993 Part to Part 6, the partial factors should be appropriate for the structure and agreed with the client NA.2.15 Partial safety factors for buildings [BS EN 1993‑1‑1:2005+A1:2014, 6.1(1)] For buildings the following partial factors should be used: γM0 = 1.00 γM1 = 1.00 γM2 = 1.10 NA.2.16 Imperfection factors for lateral torsional buckling [BS EN 1993‑1‑1:2005+A1:2014, 6.3.2.2(2)] The recommended values given in BS EN 1993-1-1:2005+A1:2014, Table 6.3 and Table 6.4 should be used 4 BRITISH STANDARD NA+A1:2014 to BS EN 1993-1-1:2005+A1:2014 NA.2.17 Lateral torsional buckling for rolled sections or equivalent welded sections [BS EN 1993‑1‑1:2005+A1:2014, 6.3.2.3(1)] For buildings and bridges the following values of λLT,0 and β should be used: a) For rolled sections and hot-finished and cold-formed hollow sections: λLT,0 = 0.4 β = 0.75 b) For welded sections: λLT,0 = 0.2 β = 1.00 BS EN 1993-1-1:2005+A1:2014, Table 6.5 should be replaced with Table NA.1: Table NA.1 Selection of buckling curve for a cross-section Cross-section Limits Buckling curve Rolled doubly symmetric I and H sections and hot-finished hollow sections h/b G b 2.0 < h/b G 3.1 c h/b > 3.1 d Angles (for moments in the major principal plane) d All other hot-rolled sections d Welded doubly symmetric sections and cold-formed hollow sections h/b G c 2.0 G h/b < 3.1 d NA.2.18 Modification factor, f [BS EN 1993‑1‑1:2005+A1:2014, 6.3.2.3(2)] The recommended expression for f should be used in which kc is given by: kc = C1 where: C1= Mcr for the actual bending moment diagram Mcr for a uniform bending moment diagram values of C1 are given in the references listed in NA.4 NA.2.19 The slenderness limit λc0 [BS EN 1993‑1‑1:2005+A1:2014, 6.3.2.4(1)B] For I, H, channel and box sections used in buildings the value of λc0 should be taken as 0.4 NA+A1:2014 to BS EN 1993-1-1:2005+A1:2014 BRITISH STANDARD NA.2.20 Modification factor, kfl [BS EN 1993‑1‑1:2005+A1:2014, 6.3.2.4(2)B] The value of the modification factor kfl should be taken as: kfl = 1.0 for hot rolled I-sections; kfl =1.0 for welded I-sections with h/b G 2; kfl = 0.9 for other sections NA.2.21 Interactions factors kyy, kyz, kzy and kzz [BS EN 1993‑1‑1:2005+A1:2014, 6.3.3(5)] The interaction factors kyy, kyz, kzy, kzz for doubly symmetric sections may be determined using either alternative Method (given in BS EN 1993-1-1:2005+A1:2014, Annex A) or alternative Method 2 (given in BS EN 1993-1-1:2005+A1:2014, Annex B) Alternative Method 2 (given in BS EN 1993-1-1:2005+A1:2014, Annex B) may also be used for sections that are not doubly symmetric when modified in accordance with NA.3.2 NA.2.22 General method for lateral and lateral torsional buckling of structural components [BS EN 1993‑1‑1:2005+A1:2014, 6.3.4(1)] This method is only valid for nominally straight components subject to in-plane monoaxial bending and/or compression In this method χop should be taken as the minimum value of χ and χLT Where χ is determined in accordance with BS EN 1993-1-1:2005+A1:2014, 6.3.1 for lateral buckling and χLT is determined in accordance with BS EN 1993-1-1:2005+A1:2014, 6.3.2 for lateral torsional buckling NA.2.23 Vertical deflections [BS EN 1993‑1‑1:2005+A1:2014, 7.2.1(1)B] Table NA.2 gives suggested limits for calculated vertical deflections of certain members under the characteristic load combination due to variable loads and should not include permanent loads Circumstances may arise where greater or lesser values would be more appropriate Other members may also need deflection limits On low pitch and flat roofs the possibility of ponding should be investigated Table NA.2 Suggested limits for vertical deflections Vertical deflection Cantilevers Length/180 Beams carrying plaster or other brittle finish Span/360 Other beams (except purlins and sheeting rails) Span/200 Purlins and sheeting rails To suit the characteristics of particular cladding 6 BRITISH STANDARD NA+A1:2014 to BS EN 1993-1-1:2005+A1:2014 NA.2.24 Horizontal deflections [BS EN 1993‑1‑1:2005+A1:2014, 7.2.2(1)B] Table NA.3 gives suggested limits for calculated horizontal deflections of certain members under the characteristic load combination due to variable load Circumstances may arise where greater or lesser values would be more appropriate Other members may also need deflection limits Table NA.3 Suggested limits for horizontal deflections Horizontal deflection Tops of columns in single-storey buildings except portal frames Height/300 Columns in portal frame buildings, not supporting crane runways To suit the characteristics of the particular cladding In each storey of a building with more than one storey Height of that storey/300 NA.2.25 Dynamic effects [BS EN 1993‑1‑1:2005+A1:2014, 7.2.3(1)B] Reference should be made to specialist literature as appropriate For floor vibrations see NA.4 NA.2.26 Hollow section buckling lengths in lattice girders [BS EN 1993‑1‑1:2005+A1:2014, BB.1.3(3)B] The recommended values may be used and further information is given in NA.4 NA.2.27 Selection of execution class [BS EN 1993-1-1:2005+A1:2014, C.2.2(3) and C.2.2(4)] NA.2.27.1 General BS EN 1993-1-1:2005+A1:2014, Table C.1 should not be adopted Decisions for the selection of reliability class and consequences class are given in clause NA.2.27.2 Decisions for the selection of execution class (EXC) are given in clause NA.2.27.3 NA.2.27.2 Selection of reliability class and consequences class If the application of design rules in a particular part of BS EN 1993 is specified in terms of reliability class (RC) or consequences class (CC), such classes should apply Otherwise it should be assumed that the design rules in BS EN 1993 are safe for classes up to and including RC2 and CC2, as defined in BS EN 1990. NA+A1:2014 to BS EN 1993-1-1:2005+A1:2014 NA.2.27.3 BRITISH STANDARD Selection of execution class Execution class should be selected taking into account the parts of BS EN 1993 and other Eurocodes that are applicable to the design of the structure The selection of execution class is given in Table NA.4 NOTE 1 In order to ensure full compatibility with the design resistance values in BS EN 1993, technical requirements in BS EN 1090-2 relating to certain execution classes might need to be enhanced Guidance is given in PD 6705-2 for designs to BS EN 1993-2 Subject to the limitations in its scope of materials and processes, PD 6705-2 might also be used to provide guidance for other designs covered by Table NA.4 If BS EN 1998 applies to a design, Quantified Service Categories F71, F90 and F112 might be deemed to apply to yielding/dissipative elements with ductility classes DCL, DCM and DCH respectively Table NA.4 Scope and conditions of application of execution class Parts of BS EN 1993 which are applicable to the design of the structure(1) All relevant Parts except Part 1-9 or Part 1-12 All relevant Parts including Part 1-9 and/or Part 1-12 Other Eurocodes applicable to the design of the structure(1) (in addition to BS EN 1990 and BS EN 1991) Required − − BS EN 1998 Optional BS EN 1994 BS EN 1994 BS EN 1994 Execution classes RC1, CC1, RC2, CC2 Minimum EXC2 Generally EXC3 Generally EXC3 RC3, CC3 EXC3 Minimum EXC3 Minimum EXC3 Note: (1) Or a distinct, clearly identifiable zone of a structure No guidance on the scope of application of EXC1 is given The scope of application of EXC1 in the NOTE to BS EN 1993-1-1:2005+A1:2014, C.2.2(4) is not endorsed for general use NOTE 2 The use of EXC1 generally provides a lower level of assurance of attaining the design resistance values in BS EN 1993 If the proposed specification of EXC1 by a specifier, either in full or in part, does not take this into account, its use might result in a higher probability of structural failure than is normally accepted for most structures in the UK. NA.3 Decisions on the status of informative annexes NA.3.1 BS EN 1993‑1‑1:2005+A1:2014, Annex A BS EN 1993-1-1:2005+A1:2014, Annex A may be used The scope of Method 1 given in Annex A should be limited to doubly symmetric sections 8 BRITISH STANDARD NA+A1:2014 to BS EN 1993-1-1:2005+A1:2014 NA.3.2 BS EN 1993‑1‑1:2005+A1:2014, Annex B BS EN 1993-1-1:2005+A1:2014, Annex B may be used Where applied to sections that are not doubly symmetric λz and χ z should be taken as the values of λ and χ from the highest value of λT to BS EN 1993‑1‑1, 6.3.1.3 or λ to BS EN 1993‑1‑1, 6.3.1.4 Where the sections are not I, H or hollow sections Class and Class sections should be designed as Class sections NA.3.3 BS EN 1993‑1‑1:2005+A1:2014, Annex AB BS EN 1993-1-1:2005+A1:2014, Annex AB may be used NA.3.4 BS EN 1993‑1‑1:2005+A1:2014, Annex BB BS EN 1993-1-1:2005+A1:2014, Annex BB may be used NA.4 References to non-contradictory complementary information References cited in this National Annex to non-contradictory, complementary information can be found at www.steel-ncci.co.uk Whilst this material is likely to be technically authoritative, not all of it has been reviewed by the UK national committee, and users should satisfy themselves of its fitness for their particular purpose In particular, they should be aware that material indicated as not having been endorsed by the committee might contain elements that are in conflict with the Eurocode NA+A1:2014 to BS EN 1993-1-1:2005+A1:2014 BRITISH STANDARD Bibliography Standards publications For dated references, only the edition cited applies For undated references, the latest edition of the referenced document (including any amendments) applies BS EN 1090-2, Execution of steel structures and aluminium structures – Part 2: Technical requirements for the execution of steel structures BS EN 1990, Eurocode – Basis of structural design BS EN 1991, Eurocode 1: Actions on structures NA to BS EN 1991-1-5, UK National Annex to Eurocode 3: Design of steel structures – Part 1-5: Plated structural elements BS EN 1993 (Parts to 6), Eurocode – Design of steel structures BS EN 1993-1-9, Eurocode 3: Design of steel structures – Part 1-9: Fatigue NA to BS EN 1993-1-10, UK National Annex to Eurocode 3: Design of steel structures – Part 1-10: Material toughness and through-thickness properties BS EN 1993-1-12, Eurocode 3: Design of steel structures – Part 1-12: Supplementary rules for high strength steels BS EN 1994, Eurocode 4: Design of composite steel and concrete structures BS EN 1998, Eurocode 8: Design of structures for earthquake resistance BS EN 10025-2:2004, Hot rolled products of structural steels – Part 2: Technical delivery conditions for non-alloy structural steels BS EN 10250-2, Open steel die forgings for general engineering purposes – Part 2: Non-alloy quality and special steels BS EN 10293, Steel castings for general engineering uses PD 6705-2 Published Document Structural use of steel and aluminium Part 2: Recommendations for the execution of steel bridges to BS EN 1090-2. Other publications [1] Castings in steel construction, SCI publication P 172, The Steel Construction Institute, Silwood Park, Ascot, Berkshire SL5 7QN 10 This page deliberately left blank NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW British Standards Institution (BSI) BSI is the national body responsible for preparing British Standards and other standards-related publications, information and services BSI is incorporated by Royal Charter British Standards and other standardization products are published by BSI Standards Limited About us Revisions We bring together business, industry, government, consumers, innovators and others to shape their combined experience and expertise into standards -based solutions Our British Standards and other publications are updated by amendment or revision The knowledge embodied in our standards has been carefully assembled in a dependable format and refined through our open consultation process Organizations of all sizes and across all sectors choose standards to help them achieve their goals Information on standards We can provide you with the knowledge that your organization needs to succeed Find out more about British Standards by visiting our website at bsigroup.com/standards or contacting our Customer Services team or Knowledge Centre Buying standards You can buy and download PDF versions of BSI publications, including British and adopted European and international standards, through our website at bsigroup.com/shop, where hard copies can also be purchased If you need international and foreign standards from other Standards Development Organizations, hard copies can be ordered from our Customer Services team Subscriptions Our range of subscription services are designed to make using standards easier for you For further information on our subscription products go to bsigroup.com/subscriptions With British Standards Online (BSOL) you’ll have instant access to over 55,000 British and adopted European and international standards from your desktop It’s available 24/7 and is refreshed daily so you’ll always be up to date You can keep in touch with standards developments and receive substantial discounts on the purchase price of standards, both in single copy and subscription format, by becoming a BSI Subscribing Member PLUS is an updating service exclusive to BSI Subscribing Members You will automatically receive the latest hard copy of your standards when they’re revised or replaced To find out more about becoming a BSI Subscribing Member and the benefits of membership, please visit bsigroup.com/shop With a Multi-User Network Licence (MUNL) you are able to host standards publications on your intranet Licences can cover as few or as many users as you wish With updates supplied as soon as they’re available, you can be sure your documentation is current For further information, email bsmusales@bsigroup.com BSI Group Headquarters 389 Chiswick High Road London W4 4AL UK We continually improve the quality of our products and services to benefit your business If you find an inaccuracy or ambiguity within a British Standard or other BSI publication please inform the Knowledge Centre Copyright All the data, software and documentation set out in all British Standards and other BSI publications are the property of and copyrighted by BSI, or some person or entity that owns copyright in the information used (such as the international standardization bodies) and has formally licensed such information to BSI for commercial publication and use Except as permitted under the Copyright, Designs and Patents Act 1988 no extract may be reproduced, stored in a retrieval system or transmitted in any form or by any means – electronic, photocopying, recording or otherwise – without prior written permission from BSI Details and advice can be obtained from the Copyright & Licensing Department Useful Contacts: Customer Services Tel: +44 845 086 9001 Email (orders): orders@bsigroup.com Email (enquiries): cservices@bsigroup.com Subscriptions Tel: +44 845 086 9001 Email: subscriptions@bsigroup.com Knowledge Centre Tel: +44 20 8996 7004 Email: knowledgecentre@bsigroup.com Copyright & Licensing Tel: +44 20 8996 7070 Email: copyright@bsigroup.com