Joint in Simple Connection Eurorode 3 PDF

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Summary

Joints in steel construction: simple Joints to eurocode 3 SCI (The Steel Construction Institute) is the leading, independent provider of technical expertise and disseminator of best practice to the steel construction sector. We work in partnership with clients, members and industry peers to help bui...

Description

Joints in steel construction:

Simple Joints to Eurocode 3

SCI (The Steel Construction Institute) is the leading, independent provider of technical expertise and disseminator of best practice to the steel construction sector. We work in partnership with clients, members and industry peers to help build businesses and provide competitive advantage through the commercial application of our knowledge. We are committed to offering and promoting sustainable and environmentally responsible solutions. Our service spans the following areas: Membership Individual and corporate membership Advice Members’ advisory service Information Publications Education Events & training

Consultancy Development Product development Engineering support Sustainability Assessment SCI Assessment Specification Websites Engineering software

The Steel Construction Institute, Silwood Park, Ascot, Berkshire, SL5 7QN. Tel: +44 (0)1344 636525 Fax: +44 (0)1344 636570 Email: [email protected] Web: www.steel-sci.com

BCSA limited is the national organisation for the steel construction industry; its Member companies undertake the design, fabrication and erection of steelwork for all forms of construction in building and civil engineering. Associate Members are those principal companies involved in the direct supply to all or some Members of components, materials or products. Corporate Members are clients, professional offices, educational establishments etc which support the development of national specifications, quality, fabrication and erection techniques, overall industry efficiency and good practice. The principal objectives of the Association are to promote the use of structural steelwork; to assist specifiers and clients; to ensure that the capabilities and activities of the industry are widely understood and to provide members with professional services in technical, commercial, contractual and health & safety matters. The Association’s aim is to influence the trading environment in which member companies have to operate in order to improve their profitability. The British Constructional Steelwork Association Limited, 4 Whitehall Court, London, SW1A 2ES. Tel: +44 (0)20 7839 8566 Fax: +44 (0)20 7976 1634 Email: [email protected] Web: www.steelconstruction.org

Publication P358

Joints in Steel Construction

Simple Joints to Eurocode 3

Jointly published by:

The Steel Construction Institute Silwood Park Ascot SL5 7QN

The British Constructional Steelwork Association Limited 4 Whitehall Court London SW1A 2ES

Tel: +44 (0) 1344 636525 Fax: +44 (0) 1344 636570 Email: [email protected] Website: www.steel-sci.com

Tel: +44 (0) 20 7839 8566 Fax: +44 (0) 20 7976 1634 Email: [email protected] Website: www.steelconstruction.org

 The Steel Construction Institute and The British Constructional Steelwork Association 2014 Apart from any fair dealing for the purposes of research or private study or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may not be reproduced, stored, or transmitted, in any form or by any means, without the prior permission in writing of the publishers, or in the case of reprographic reproduction only in accordance with the terms of the licences issued by the UK Copyright Licensing Agency, or in accordance with the terms of licences issues by the appropriate Reproduction Rights Organisation outside the UK. Enquiries concerning reproduction outside the terms stated here should be sent to the publishers, at the addresses given on the title page. Although care has been taken to ensure, to the best of our knowledge, that all data and information contained herein are accurate to the extent that they relate to either matters of face or accepted practice or matters of opinion at the time of publication, The Steel Construction Institute, The British Constructional Steelwork Association Limited, the authors and any other contributor assume no responsibility for any errors in or misinterpretations of such data and/or information or any loss or damage arising from or related to their use. Publications supplied to Members of SCI and BCSA at a discount are not for resale by them.

Publication Number: SCI P358

ISBN: 978-1-85942-201-4

British Library Cataloguing-in-Publication Data. A catalogue record for this book is available from the British Library.

ii

FOREWORD This publication is one of a series of “Green Books” that cover a range of steelwork connections. This publication provides guidance for nominally pinned joints that primarily carry vertical shear and, as an accidental limit state, tying forces, designed in accordance with Eurocode 3 and its UK National Annexes. This publication is cited in the UK National Annex: joints designed in accordance with the principles within this publication can be classed as nominally pinned without calculation. A companion publication (published in 2012) covers moment-resisting joints. Guidance for nominally pinned joints designed in accordance with BS 5950 is available in publication P212 Joints in Steel Construction; Simple Connections. The major changes in scope compared to P212 are:

● Double angle cleats are omitted from the current publication, as it was felt they are not commonly used in the UK.

● A new full depth end plate (i.e. welded to both flanges) has been introduced, which offers a significantly increased tying resistance compared to a partial depth end plate.

● The tying resistance of partial depth end plates is calculated using Eurocode provisions. The revised design model results in an increased tying resistance compared to P212. BS EN 1993-1-8 has clear definitions for connections and joints: the terms ‘joint’ and ‘connection’ refer to the zone where members are interconnected and to the location where elements meet, respectively. In this publication, the distinction in terminology is not emphasised and “connection” is used more generally, reflecting traditional practice in the UK.

This publication was produced under the guidance of the BCSA/SCI Connections Group, which was established in 1987 to bring together academics, consulting engineers and steelwork contractors to work on the development of authoritative design guides for steelwork connections.

iii

ACKNOWLEDGEMENTS The BCSA/SCI Connections Group members (2014) comprise:

Mike Banfi

Arup

David Brown

SCI

Tom Cosgrove

BCSA

Peter Gannon

Severfield (UK) Ltd

Ana Girao Coelho

University of Warwick

Bob Hairsine

CADS Ltd

Alastair Hughes

Consultant

Fergal Kelly

Peter Brett Associates

Abdul Malik

SCI

Robert Moisey

Severfield (Design & Build) Ltd

David Moore

BCSA

Chris Morris

Tata Steel

David Nethercot

Imperial College

Alan Pillinger

Bourne Construction Engineering Ltd

Alan Rathbone

CSC UK Ltd (Chairman)

Roger Reed

Consultant

Clive Robinson

Tekla

Gary Simmons

William Hare Ltd

Mark Tiddy

Cooper & Turner Limited

Robert Weeden

Caunton Engineering Ltd

The primary drafter of this publication was Edurne Nunez Moreno, with assistance from Cyrill Tarbé (both formerly of SCI) and David Brown. Abdul Malik provided additional guidance. The revisions in the 2014 reprint include revised tying resistances for full depth end plates for deeper beams, revised resistances for RHS bases, an additional example using blind bolts, revised guidance for bracing connections and typographical corrections. The revisions were completed by David Brown. Revisions are marked with a black line in the margin.

iv

PICTORIAL INDEX

Partial depth end plates Pages 10 - 82 Tables G.1 - G.7

Full depth end plates Pages 83 - 107 Tables G.8 - G.14

Fin plates Pages 108 - 171 Tables G.15 - G.21

Column splices Pages 172 - 235 Tables G.22 - G.29 Bracing connections Pages 258 - 264 Column bases Pages 236 - 257 Tables G.30 - G.35

v

CONTENTS PAGE Foreword

iii 

Acknowledgements

iv 

Pictorial Index

v 

1 

Introduction 1.1  About this publication 1.2  Joint considerations 1.3  Exchange of information 1.4  Costs 1.5  Sustainability 1.6  Major symbols

1  1  1  2  2  3  4 

2 

Standardised connections 2.1  The benefits of standardisation 2.2  Components 2.3  Geometry

5  5  6  6 

3 

Beam to beam and beam to column connections 3.1  Introduction

9  9 

4 

End plates 4.1  Introduction 4.2  Practical considerations 4.3  Recommended geometry 4.4  Design 4.5  Design procedures for partial depth end plates 4.6  Worked examples with partial depth end plates 4.7  Design procedures for full depth end plates 4.8  Worked examples with full depth end plates

5 

Fin plates 5.1  Introduction 5.2  Practical considerations 5.3  Recommended geometry 5.4  Design 5.5  Design procedures 5.6  Worked examples

108  108  109  109  111  113  136 

6 

Column splices 6.1  Introduction 6.2  Practical considerations 6.3  Recommended geometry 6.4  Design 6.5  Design procedures for cover plate splices for I section columns – Bearing type 6.6  Design procedures for cover plate splices for I columns –Non-bearing type 6.7  Design procedures for hollow section ‘cap and base’ splices in tension 6.8  Design procedures for CHS end plate splice in tension 6.9  Worked examples

172  172  173  174  174  175  184  197  202  208 

7 

Column bases 7.1  Introduction 7.2  Practical considerations 7.3  Recommended geometry 7.4  Design 7.5  Design procedures 7.6  Worked examples

236  236  236  238  239  240  245

 

vi

10  10  10  12  13  13  31  83  96 

8 

Bracing connections 8.1  Introduction 8.2  Angles, channels and flats 8.3  Hollow sections 8.4  Gusset plates 8.5  Buckling resistance 8.6  Large bracing forces 8.7  Effects of bracing connections on joint performance

258  258  258  259  259  261  264  264 

9 

Special connections 9.1  Introduction

265  265 

10 

References

274 

Appendix A  Structural integrity A.1  General A.2  Prying and tying forces

277  277  277 

Appendix B  Tying resistance of partial depth and full depth end plates B.1  Partial depth end plates B.2  Full depth end plates

278  278  278 

Appendix C  C.1  C.2  C.3  C.4 

Welds for end plate and fin plate connections Basic rules End plate welds subject to shear Fin plate welds Alternative weld design

279  279  279  280  280 

Appendix D  D.1  D.2  D.3  D.4 

Thermal drilling of hollow sections Introduction Drilling tool and process Application & limitations Further information

281  281  281  281  282 

Appendix E  E.1  E.2  E.3  E.4  E.5 

Hollo-bolt connections to hollow sections introduction Installation Material options Sealing options Further information

283  283  283  284  284  284 

Appendix F  F.1  F.2  F.3  F.4  F.5 

Blind bolt connections to hollow sections Introduction Installation Material Bolt resistances Further information

285  285  285  285  285  285 

Appendix G  Resistance tables; Material strengths; Fastener resistances; Dimensions for detailing; Section dimensions and properties Appendix H  H.1  H.2  H.3 

T - 1  T - 183  T - 183  T - 183  T - 183 

Section designations Introduction Open sections Hollow sections

vii

viii

1

INTRODUCTION

1.1

ABOUT THIS PUBLICATION

This publication provides procedures for designing joints in steel-framed structures in accordance with BS EN 1993-1-8[1] and its accompanying National Annex[2], and with BS EN 1993-1-1[3] and its National Annex[4].Connections between UK Beams (“universal beams”) and UK Columns (“universal columns”) using non-preloaded and preloaded bolts are included. Connections between UK Beams and hot finished structural hollow section columns using the Flowdrill and Hollo-Bolt systems are also included. Design procedures are provided for:

The design guidance for hollow section columns is restricted to hot finished structural hollow sections.

(a) Beam to beam and beam to column connections

Design examples

● ● ●

Resistance tables Resistance tables for standard connections are provided in the yellow pages of this guide. The resistance tables have been arranged so that the designer can simply select a connection and, with the minimum of calculation, check whether it has sufficient resistance.

Worked examples illustrating the design procedures and the use of resistance tables are included.

Partial depth end plates Full depth end plates Fin plates

1.2

(b) Column splices

JOINT CONSIDERATIONS

Joint classification

Bolted splices, which may be cover plate or end plate type.

According to BS EN 1993-1-8, nominally pinned joints: (1) should be capable of transmitting the internal forces, without developing significant moments which might adversely affect the members or the structure as a whole and (2) be capable of accepting the resulting rotations under the design loads

(c) Column bases Steel plates welded to column shafts.

(d) Bracing connections General guidance is provided for connections between bracing members and main members, via a gusset plate. Typical details are shown.

In addition, the joint must: (3) provide the directional restraint to members which has been assumed in the member design (4) have sufficient robustness to satisfy the structural integrity requirements (tying resistance).

(e) Special connections General guidance is given on special connections, where, for example, members do not align on a common centreline, align at different levels or at an angle.

Steel grades

BS EN 1993-1-8 requires that all joints must be classified; by stiffness, which is appropriate for elastic global analysis, or by strength, which is appropriate for rigid plastic global analysis, or by both stiffness and strength, which is appropriate for elastic-plastic global analysis.

This publication covers steel conforming to BS EN 10025-2[5] and BS EN 10210[6]. Within this publication, reference is only made to the strength designation; the sub-grade is required for a complete specification.

Classification by stiffness: the initial rotational stiffness of the joint, calculated in accordance with BS EN 1993-1-8, 6.3.1 is compared with the classification boundaries given in BS EN 1993-1-8, 5.2.2.

Design procedures Individual design procedures are included for all connection components. The procedures commence with the detailing requirements (joint geometry), then present the checks for each stage of the load transfer through the connection including welds, plates, bolts and the section webs or flanges as appropriate. The resistance checks on sections, welds and bolts are all based on Eurocode 3.

Alternatively, joints may experimental evidence, satisfactory performance calculations based on test

1

be classified based on experience of previous in similar cases or by evidence.

Introduction – Exchange of information

Classification by strength: the following two requirements must be satisfied in order to classify a joint as nominally pinned, based on its strength: (1) the design moment resistance of the connection does not exceed 25% of the design moment resistance required for a full-strength joint (2) the joint should be capable of accepting the rotations resulting from the design loads.

connection. Common practice is to design such connections without utilising the benefits of the continuity of reinforcement through the concrete slab. However, Joints in steel construction: Composite connections[9], enables reinforcement continuity to be allowed for in providing relatively simple full depth end plate connections with substantial moment resistance.

The UK National Annex to BS EN 1993-1-8 states that connections designed in accordance with this publication* may be classified as nominally pinned joints.

The design of the frame and its connections is usually carried out in one of the following ways: (1) The frame is designed by the Consulting Engineer and the connections are designed by the Steelwork Contractor (2) The frame and the connections are designed by the Steelwork Contractor (3) The frame and its principal connections are designed by the Consulting Engineer.

1.3

All the standard connections given in this publication may be classified as nominally pinned according to the strength requirements. Care should be taken before amending the standard details as the resulting connection may fall outside the provisions of the UK National Annex (UK NA). In particular:

EXCHANGE OF INFORMATION

If the frame and connections are not designed by a single authority, care must be taken to ensure that design requirements for the connections are clearly defined in the contract and on the design drawings.

● the rotation capacity of the standard fin plate details have been demonstrated by test

● the thickness of the full depth end plates have been limited to ensure the moment resistance is less than 25% of a full strength joint.

The National Structural Steelwork Specification for Building Construction[10] gives guidance on the transfer of necessary information. The following items should be considered a minimum:

Structural integrity The UK Building Regulations require that all buildings should be designed to avoid disproportionate collapse. Commonly, this is achieved by designing the joints in a steel frame (beam to column, beam to beam, beam through beam and column splices) for tying forces. Guidance on the design values of tying forces is given in BS EN 1991-1-7[7] Annex A, and its UK National Annex[8]. The requirements relate to the building Class, with a design value of horizontal tying force generally not less than 75 kN, and usually significantly higher. The full depth end plate details have been developed to provide an increased tying resistance compared to the partial depth details.

● a statement describing the design concept ● drawings, or equivalent electronic data, showing the size, grade and position of all members

● the design standards to be used ● the forces required to be transmitted by each connection

● whether the forces shown are factored or unfactored

● requirements for any particular type of fabrication detail and/or restriction on the type of connection to be used.

1.4

Appendix A and Appendix B give information on the behaviour and methodology for designing connections to resist tying forces.

COSTS

Simple connections are invariably cheaper to fabricate than moment-resisting connections, because they provide a...