PP Connection Design According to en 1993-1-8

Helsinki University of Technology Laboratory of Steel Structures Publications 33 Teknillisen korkeakoulun teräsrakennetekniikan laboratorion julkaisuja 31 Espoo 2007

TKK-TER-33

DESIGN OF STRUCTURAL CONNECTIONS TO EUROCODE Preview of MS Power Point presentations F. Wald

AB

TEKNILLINEN KORKEAKOULU TEKNISKA HÖGSKOLAN HELSINKI UNIVERSITY OF TECHNOLOGY TECHNISCHE UNIVERSITÄT HELSINKI UNIVERSITE DE TECHNOLOGIE D’HELSINKI

List of Lessons Lessons at Seminar Seminar

Introduction Lessons Connection Design accordi ng to EN 19931993-1-8 1-8 Prof. František Wald Czech Technical Technical University in Prague Prague

1. 2. 3. 4. 5. 6. 7. 8. 9.

Intr ntroduc oducttion ion Bases Bases of of desig designn accord according ing to EN EN 19931993-1-8 1-8 Weld Welded ed conn connec ectition onss Bolte oltedd conn connec ecttions ions Basi Basics cs of stru struct ctur ural al join joints ts Desi Design gn of of simp simple le con conne nect ctio ions ns Colum lumn bases Fire Fire desig designn of connec connectio tions, ns, EN 1993 1993-1-1-22 Seis Seismi micc desi design gn,, EN 1998 1998-1 -1-1 -1

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Summary 

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List of content Timing National Annexes CeStruCo Access STEEL Summary

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List of Content Content in EN 1993-1-8 1993-1-8 1. 2. 3. 4. 5. 6. 7.

Lessons in Window Help Format with PP Presentations

CeStruCo

Introduction Bas Basis of des design ign Connec Connectio tions ns made made with with bolt bolts, s, rivet rivetss or pins pins Weld Welded ed conn connec ectition onss Analys Analysis, is, classi classific ficati ation on and and mode modellin llingg Struct Structura urall join joints ts connec connectin tingg H or I sections Holl Hollow ow sec sectition on joi joint ntss

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Summary 

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Development of Eurocodes  


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CeStruCo

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ECCS Concept in 1978 ECCS First draft in 1984 CEN Started with Eurocodes in 1990 CEN ENV 199x-x-x in 1992 (actions nationally only) CEN EN 199x-x-x in 2005 Advantages 

 

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Weakness  

5

European agreement All structural materials under one safety concept Copyrights Size (some countries only rules, some textbooks) 6

List of Lessons Lessons at Seminar Seminar

Introduction Lessons Connection Design accordi ng to EN 19931993-1-8 1-8 Prof. František Wald Czech Technical Technical University in Prague Prague

1. 2. 3. 4. 5. 6. 7. 8. 9.

Intr ntroduc oducttion ion Bases Bases of of desig designn accord according ing to EN EN 19931993-1-8 1-8 Weld Welded ed conn connec ectition onss Bolte oltedd conn connec ecttions ions Basi Basics cs of stru struct ctur ural al join joints ts Desi Design gn of of simp simple le con conne nect ctio ions ns Colum lumn bases Fire Fire desig designn of connec connectio tions, ns, EN 1993 1993-1-1-22 Seis Seismi micc desi design gn,, EN 1998 1998-1 -1-1 -1

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Summary 

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List of Content Content in EN 1993-1-8 1993-1-8 1. 2. 3. 4. 5. 6. 7.


CeStruCo

Introduction Bas Basis of des design ign Connec Connectio tions ns made made with with bolt bolts, s, rivet rivetss or pins pins Weld Welded ed conn connec ectition onss Analys Analysis, is, classi classific ficati ation on and and mode modellin llingg Struct Structura urall join joints ts connec connectin tingg H or I sections Holl Hollow ow sec sectition on joi joint ntss

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Summary 

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Development of Eurocodes  


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CeStruCo

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ECCS Concept in 1978 ECCS First draft in 1984 CEN Started with Eurocodes in 1990 CEN ENV 199x-x-x in 1992 (actions nationally only) CEN EN 199x-x-x in 2005 Advantages 

 



Weakness  

5

European agreement All structural materials under one safety concept Copyrights Size (some countries only rules, some textbooks) 6

List of Eurocodes    

EN 1990 1990 EN 1991 1991 EN 1992 EN 1993 1993

Euroco Eurocode de 0: Euroco Eurocode de 1: 1: Eurocode Eurocode 2: Euroco Eurocode de 3:

Eurocodes List of Actions Basis Basis of Struc Structur tural al Desig Designn Action Actionss on struct structure uress Design Design of of concr concrete ete structures structures Design Design of of steel steel structu structures res

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Project team Prof. F. Bijlaard 

EN 1991-1-1 1991-1-1 Actions Actions – Dead load published published 04/02 EN 1991-1-2 Actions – Fi Fire 11/02 EN 1991-1-3 Actions – Sn Snow 07/03 EN 1991-1-4 Actions – Wi Wind 04/05 EN 19 1991-1-5 Ac Actions – T em emperature 11/03 EN 1991-1-6 Actions – During erection 06/05 EN 19 1991-1-7 Ac Actions – Ex Exceptional 05/06 EN 1991-2 1991-2 Action Actionss – Transp Transport ort on bridge bridgess 09/03 09/03 EN 1991-3 Actions – Crane girders 11/06 EN 1991-4 Actions – Silos and tanks 08/05

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EN 1994 1994 Eurocode Eurocode 4: Design Design of compos composite ite steel steel and and concrete concrete struc. struc. Project team Prof. D. Anderson

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EN 1995 1995 EN 1996 1996 EN 1997 1997 EN 1998 1998 EN 1999

Euroco Eurocode de 5: Euroco Eurocode de 6: Euroco Eurocode de 7: 7: Eurocode Eurocode 8: Eurocode Eurocode 9:

Design Design of of timber timber struc structur tures es Design Design of mason masonry ry struct structure uress Geotec Geotechni hnica call design design Design Design of structu structures res for for earthquak earthquakee resistanc resistancee Design Design of of alumin aluminium ium structures structures 7

Structural Steel Eurocodes                    

EN 1993-1-1 EN 1993-1-2

B as i c r u les Fir e r es i st an c e

EN 1993-1-3 EN 19 1993-1-4 EN 1993-1-5 EN 1993-1-6 EN 1993-1-7 EN 1993-1-8 EN 1993-1-9 EN 1993-1-10 EN 1993 1993-1 -1-1 -111 EN 1993-1-12 EN 1993-2 EN 1993-3-1 EN 1993-3-2 EN 1993-4-1 EN 1993-4-2 EN 1993-4-3 EN 1993-5 EN 1993- 6

Thin walled Corrosion re resistant Plates Shells Plates 2 Con n ec t i on s Fa t i g u e B r i t t l e f r ac t u r e Tens Tensilile mem membe bers rs (cab (cable les) s) HSS Bridges Mast Chimneys Silos Tanks Pipelines Pilots Crane girders

(20 documents) Fir s t pa pac k age

05/05 04/05

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05/05 05/05 05/05      

Eurocode Eurocode Implementa Implementation tion - Examples Examples

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ECCS TC10 comments to ENV 1993-1-1 CEN/TS250/SC3 project team, team, head Mr. Jouko Kouhi Kouhi prEN 1993-1-8 document N 1054 E 900 national comments Final draft Voting Acceptation by CEN

Czech Rep. 8/2006

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National Annexes UK 12/200 12/2007; 7; France France 12/20 12/2006; 06; Polan Polandd 2010; 2010;

Chapter 6 Connections Annex J Joints Annex L Base plates Annex K Hollow section joints May 12, 1992 VTT, Finland Sept. 9, 2001 Nov. 20, 2001 April 16, 2004 May 10 11, 2005

Summary

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France 12/2006; Poland 2007;

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Development of EN 1993-1-8 From ENV 1991-1

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Translations UK N/A;

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Czech Czech Rep. Rep. 8/2006 8/2006

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Eurocodes Eurocodes be adopted adopted for governme government nt construction construction UK unknown; France Not; Poland 2010; Czech Rep. 2008

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Eurocodes Eurocodes be adopted adopted for non-gove non-governme rnment nt construction construction UK unknown; France Not; Poland 2010; Czech Rep. 2008

List of content Timing National Annexes CeStruCo Access STEEL Conclusions


CeStruCo

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National National standards standards withdrawn withdrawn UK 2010 2010;; Fran France ce 2010 2010;;

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Pola Poland nd 2010 2010;;

Czec Czechh Rep. Rep. 2010 2010 11

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National Annex for EN 1993-1-8 

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National Choice (Czech Rep.) Clause 1.2.6 Reference Standards, Group 6: Rivets

Alternative procedures Nationally Determined Parameters

ČSN 02 2300: Rivets, Overview (Czech national standards).

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Clause 2.2 Partial safety factors, paragraph (2)

National choice is allowed in EN 1993-1-8 through (only): 1.2.6(6) Reference standard Rivets 2.2(2) Partial safety factors 3.1.1(3) Bolt classes 3.4.2(1) Hand tightening of the nut is considered adequate 5.2.1(2) Classification of joints 6.2.7.2(9) Requirements for elastic distribution of forces in bolt rows 

Clause 3.1.1(3) General, paragr aph (2) 

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Numerical values of partial safety factors for joints are not changed, the values in Table 2.1 should be used.

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All bolt classes listened in Table 3.1 may be used.

Clause 3.4.2 Tension connections, paragraph (1) If the preload is not explicitly required in design for slip resistance, the hand tightening of the nut is considered adequate without the control of preload.

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Clause 5.2.1 General, paragr aph (2) No additional information on classification of joints by their stiffness and strength are given to that included in 5.2.1(2).

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Clause 6.2.7.2 Beam-to-column joints with bolted end-plate connections, paragraph (9)

CeStruCo = Civil enginnering Stru ctural Co nnections

Summary 

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The requirements for elastic distribution of forces in the bolt rows introduced 14 in (6.26) are not changed.

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CeStruCo

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Aristotle University of Thessaloniki, Greece Bouwen met Staall, Netherlands Building Research Establishment Ltd., United Ki ngdom Czech Technical University (contractor), Czech Republic Luleå University of Technology, Sweden University of Coimbra, Portugal Politechnica University of Timisoara, Romania

Review KREKON Design office, Rotterdam, Netherlands Czech EXCON a.s., Prague, Czech Republic Constructional Steelwork Association Ostrava, CR   

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Textbook

European Educational Projects 

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ESDEP WIVISS SteelCall Stainless SteelCall SSEDTA CeStruCo NFATEC SDCWASS DIFISEK

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Basic European educational project CD lessons Virtual office Internet/CD PP presentation + lessons Connection design Internet courses Austenitic stainless steel Fire design 17

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

Introduction Bolts Welding Structural Modelling Simple Connections Moment Resistance Connections Column Bases Seismic Design Fire Design Hollow Section Joints Cold-Formed Member Joints Aluminium Connections Design Cases 18

Internet / CD Version 

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Lessons in Window help format Textbook in PDF file Worked examples Presentations 

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Lessons in Window Help Format

PowerPoint Programme „Nonlinear analyses of joints by component method“ Video film

Tools for connection design 

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Example of Software Example of Tables 19

PowerPoint Presentations

Prepared by RoboHelp tool at Czech Technical University in Prague

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Software

Non-linear Analysis of Steel Connections

Based on Fire test on 8th storey building Cardington, January 16, 2003

Coimbra University Prediction of behaviour by component method with nonlinear force - deformation diagram of components 21

Video Film

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CeStruCo on CD 

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Statically Stressed Bolts in Dynamically Loaded Connections prepared at Delft University

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Educational material to support conversion of ENV 1993-1-1 to EN1993-1-8 CD / Internet lessons

www.fsv.cvut.cz/cestruco


CeStruCo

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Access STEEL – Informational tool at www.access-steel.com

Summary 

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CeStruCo

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Access STEEL – Information System 

Access STEEL - Documents

Eurocodes 1993-1-x and EN 1994-1-x for not steel specialists   

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Project Initiation Scheme Development Detailed Design Verification

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For practising designers, architects and their clients     

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Multi-storey Buildings Single Buildings Residential Construction 

Detailed design of elements Step-by-step guidance Full supporting information Worked examples Interactive worked examples

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250 separate technical resources + 50 interlinked modules 

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English, French, German and Spanish Project of EU eContent Programme

Client's guide Concept designs Flow Charts 

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Example - Client's Guide

Fire Safety Engineering

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Non-conflicting Complementary Information Workedexamples (Pasive and Interactive)

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Example - Concept Designs

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Example - Flow Charts

Example - Non-Conflicting Complementary Information

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Example – Pasive Worked Example

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Example – Interactive Worked Example

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Access STEEL 

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Summary

Informational system based on hypertext engine

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EN 1993-1-8 – Connectors and joints EN 1993-1-8 – Will be used from 2007 (mostly) CeStruCo – Educational material to EN 1993-1-8 Access STEEL – Informational tool for EC3 on internet

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List of Lessons at Seminar 1. 2. 3. 4. 5. 6. 7. 8. 9.

Bases of Design according to EN 1993-1-8 Lessons Connection Design according to EN 1993-1-8 Prof. František Wald

Introduction Bases of design according to EN 1993-1-8 Welded connections Bolted connections Basics of structural joints Design of simple connections Column bases Fire design of connections, EN 1993-1-2 Seismic design, EN 1998-1-1

1

Topics

2

General Requirements 

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Bases of Design

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Eccentricity at Intersections

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Connection Modelling in Global Analyses

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Global Analysis of Lattice Girders

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Classification of Joints

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Modelling of Beam-to-Column Joints

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Summary

All joints should have a design resistance such that the structure is capable of satisfying all the basic design requirements given in EN 1993-1-1.

3

Partial safety factors for joints       

4

Applied Forces and Moments

Resistance of members and cross-sections M0, M1, M 2 Resistance of bolts, rivets, pins, welds, plates in bearing M2 Slip resistance , M3,ser M3 Bearing resistance of an injection bolt M4 Resistance of joints in hollow section lattice girder M5 Resistance of pins at serviceability limit state M6,ser Preload of high strength bolts M7

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The forces and moments applied to joints at the ultimate limit state should be determined according to the principles in EN 1993-1-1.

 Recommended values   

M3 = 1,25 (EN 1993-1-1 = M3,ser M7 = 1,10 M4 = M5 = M6,ser = 1,00

M2

=

M0

= 1,00,

M1

= 1,10)

Frequency bar chart Effect of actions

Resistance

5

6

Resistance of Joints

Topics

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On the basis of the resistances of its basic components

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Linear-elastic or elastic-plastic analysis

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Fasteners with different stiffnesses

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Bases of Design

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With the highest stiffness should be designed to carry the load.

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(An exception bolts and slip resistant bolts).

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Summary

7

Reduction of Resistance of Angles Connected by One Leg

Eccentricity at Intersections 

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(and other unsymmetrically connected members in tension)

The joints and members should be designed for the resulting moments and forces 

8

Except in the case of particular types of structures - lattice girders

In the case of joints of angles or tees attached by either a single line of bolts or two lines of bolts

With 1 bolt:

N u,Rd

=

With 2 bolts:

N u,Rd

=

With 3 or more bolts:

N u,Rd

=

2,0(e2 −0,5d 0 )t f u γ M 2 β 2 Anet f u γ M 2

Centroidal axes

β 3 Anet f u

Reduction factors

Fasteners

Fasteners

Pitch

p1

< 2,5 do

> 5,0 do

2 bolts

β 2

0,4

0,7

3 bolts or more β 3

0,5

0,7

γ M 2

Setting out lines 9

Topics 

Bases of Design

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Summary

10

Types of Joint Modelling STIFFNESS

Rigid Semi - rigid Pinned

11

RESISTANCE Full-strength

Partial-strength

Pinned

Continuous

Semi-continuous

-

Semi-continuous Semi-continuous

-

-

-

Simple

12

Elastic analysis at the Serviceability Limit State

Elastic analysis at the Ultimate Limit State

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Modified stiffness S j,ini and resistance M j,Rd

Design joint properties based on the type of global analysis 

Initial stiffness S j,ini and resistance M j.Rd M

M

S j,ini

M j,Rd

2 M 3 j,Rd M j,Sd

M j,Sd

S j,ini

S j,ini / η φ

φ η

is stiffness modification coefficient

13

Stiffness Modification Coefficient

η M M j,Rd M j,Sd

14

Rigid - Plastic Analysis

S j,ini

Resistance M j,Rd and deformation capacity φ Cd

S j,ini / η φ

Type of connection

M

Other types of joints (beam-to-beam joints, Beam-to-column joints beam splices, column base joints)

Welded

2

3

Bolted end-plates

2

3

Bolted flange cleats

2

3,5

Base plates

-

3

M j,Rd

φ Cd

φ

15

Elastic - Plastic Analysis 

16

Joint Modelling and Frame Global Analysis

Full curve description

MODELLING

M M j,Rd

TYPE OF FRAME ANALYSIS Elastic analysis

Rigid-plastic analysis

Elastic-plastic analysis

Continuous

Rigid

Full-strength

Rigid/full strength

Semicontinuous

Semi-rigid

Partial-strength

Rigid/partial-strength Semi-rigid/full-strength Semi-rigid/partial-strength

Pinned

Pinned

Pinned

S j,ini Simple

φ Cd

φ 17

18

Topics

Global Analysis of Lattice Girders 

Hollow sections

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Bases of Design

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Secondary moments (due to rigidity of joints)

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Moments resulting from transverse loads

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Moments resulting from eccentricities

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Summary

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Assumption the members connected by pinned joints (for the distribution of axial forces)

Type of component

Source of the bending moment Secondary effects

Transverse loading

Eccentricity

Compression chord Tension chord Brace member

Yes Not if criter. is satisfied

No

Yes

Joint

No Not (if criter. is satisfied)

19

20

Secondary Moments

Moments Resulting from Transverse Loads

Moments, caused by the rotational stiffness's of the joints, may be neglected in the design of members and joints.

Momets should be taken into account in the design of the members to which they are applied

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Joint geometry is within the range

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Ratio of the system length to the depth of the member in the plane is not less than 6

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Brace members may be considered as pin-connected to the chords.  Moments resulting

from transverse loads applied to chord members need not be distributed into brace members, and vice versa.

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Chords may be considered as continuous beams, with simple supports at panel points.

21

Moments resulting from Eccentricities 

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22

Moments resulting from Eccentricities

Centric

Negative eccentricity

Positive eccentricity 23

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May be neglected in the design of tension chord members and brace members

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May be neglected in the design of connections if the eccentricities are within the limits:  −0,55

d 0

≤

e ≤ 0,25 d 0

 −0,55

h0

≤

e ≤ 0,25 h0

e

eccentricity

d 0

diameter of the chord

h0

depth of the chord, in the plane of the lattice girder 24

Topics

Based on Resitance

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Bases of Design

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Summary

Moment, M M b,pl,Rd

Full strength connection Partial strength connection Bending moment resistance of connected beam

Rotation, φ 25

Based on Stiffness

26

Based on Rotational Capacity

(Values for Column Bases)



 Accuracy of calculation 

5% Ultimate Limit State



20% Serviceability Limit State

Moment, Elastic rotation M of connected beam

Relative moment M j / M pl,Rd 1,0

E I c φ

0,4

S j.ini.c.s = 12 E I c / Lc

0,2

Semi-rigid column base 0

0,01

0,002

Semi-ductile connection Brittle connection

λ o = 1,36

φ

M

(Class 2) (Class 3)

28

Column Bases – Braced Frames 

Prediction of column resistance based on the lower support bending stiffness Relative stiffness of base plate S j.ini Simplified boundary E I c / L c 50 40 30 20 10 0

M φ

Rotation, φ

Pinned column base φ , rad 0,003 27

Column Bases – Braced Frames 

M

Ultimate rotation of connected beam Ductile connection (Class 1)

L c M c,pl,Rd

S j.ini.c.n = 30 E I c / Lc

0,6

0

_ φ =

Rigid column base

0,8

Deformation capacity of connected member

Accurate boundary

Prediction of column resistance based on the lower support bending stiffness is the limit S j .ini

for

λ ≤ 0 ,5

for

0 ,5 < λ < 3 ,93 is the limit S j .ini

and for 3 ,93 ≤ λ

is the limit S j .ini

>

0,

≥ 7 ( 2 λ − 1 ) E I c / Lc ,

≥

48 I c / Lc .

The limiting stiffness 12 E I c / Lc (slenderness lower than λ = 1 ,36 ) 0

2

4 6 8 10 λ 0 Relative slenderness of column

29

30

Classification of Joints 

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Topics

National Annex may give additional information on the classification of joints by their stiffness and strength in Cl 5.2.2.1(2) Pin is difficult to define

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Bases of Design

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Small moment resistance

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Small stiffness

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Summary

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High deformation/rotational capacity 31

32

Shear Panel

Modelling of Joint by Rotational Springs 

Component method

  



M b

a

M a



φ a  T

M b

φ b

Joint

Forces and moments acting on the joint

Shear panel

Shear panel

separatelly

in connections 33

Distribution of Internal Forces

z 3

z 2

N b1,Ed Mb1,Ed

Forces and moments acting on the web panel at the connections



Bases of Design




=

F t1.Rd

= F t1.Rd

=

F t2.Rd

< F t2.Rd

=

F t3.Rd

< F t3.Rd

< F t3.Rd




≤

F c.Rd

F c.Rd












Summary

t2.Rd

≤

F c.Rd

Elastic-plastic distribution

34

Topics

≤

Elastic distribution

Shear forces 

Vb1,Ed

F

F t1.Rd

Plastic distribution



Vb2,Ed

M b2,Ed

=

=

z 1

N b2,Ed

A bolt row in shear only



Rest of shear resistance of each bolt row



Supplement of shear resistance of each bolt row

35

36


Welded Connections Lessons Connection Design according to EN 1993-1-8 Prof. František Wald


1

Topics 

Bases of design



Fillet weld

Bases of Design Fillet welds



But weld

Design model



Design independent of the direction of loading



Plug welds



Very long welds



Groove welds



Design example



Effective width of welded beam-to-column connection



Weld design for full resistance of connecting members

Welding in cold-formed zones



Design of partially penetrated butt weld

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Summary

a

EN 1993-1-8 requirements Design rules + Design models

3

Fillet welds – Definition of Effective Throat Thickness a

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2

4

Topics

The effective throat thickness of a fillet weld should not be less than 3 mm



Bases of design

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Fillet weld Design model



Design of independent of the direction of loading



Very long welds



Example - Modelling the resistance




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Design of Partially Penetrated Butt Weld



Summary

Design throat thickness of flare groove welds in rectangular structural hollow section 5



6

Plane Stresses

Design Model of Fillet Welds



Huber –Misses- Henckey condition of plasticity (HMH) 



Triaxial state of stress (needed exceptionally only) Plane state of stress (needed very often)

σ + σz2 - σx2 σz2 + 3τ2 ≤ (f y / γM) 2 2 x

σ z σ x

a

σ ┴ σ║ τ ┴ τ║

effective throat thickness of the fillet weld normal stresses perpendicular to the throat normal stresses parallel to the axis of weld (omitted) shear stresses perpendicular to the axis of weld shear stresses parallel to the axis of weld



σ ≤ f y / γM0 τ ≤ f y / (γM0 √3) 7

(

σ⊥ + 3 τ⊥ + τ 2

2 II

)

Standard and steel grade

≤ f u (β w γ Mw )

σ⊥ ≤ f u γ Mw Ultimate tensile strength of connected material

f u

8

Correlation factor βw for fillet welds

Design Model 2

Uniaxial state of stress (from the material tests)

βw Correlation factor

EN 10025

EN 10210

EN 10219

Correlation factor β w

S 235 S 235 W

S 235 H

S 235 H

0,80

S 275 S 275 N/NL S 275 M/ML

S 275 H S 275 NH/NLH

S 275 H S 275 NH/NLH S 275 MH/MLH

0,85

S 355 S 355 N/NL S 355 M/ML S 355 W

S 355 H S 355 NH/NLH

S 355 H S 355 NH/NLH S 355 MH/MLH

0,90

S 420 MH/MLH

1,00

S 460 NH/NLH S 460 MH/MLH

1,00

S 420 N/NL S 420 M/ML γMw partial safety factor for material of

welds 9

Topics 

Bases of design



Fillet weld 

Design model



Design independent of the direction of loading



Very long welds


















Summary

S 460 N/NL S 460 M/ML S 460 Q/QL/QL1

S 460 NH/NLH

10

Design Independent of the Direction of Loading N ⊥ Sd F w,Rd

F w,Sd F w,Rd V ⊥,Sd

La

V //,Sd

f vw ,d =

f u 3 β w γ Mw

F w ,Rd = a f vw ,d 11

12

Topics

Very Long Welds



Bases of design



Fillet weld





Design model






Very long welds



Design example















Summary

τ//

τ//

τ //

14



Bases of design



Fillet weld

β Lw

0,8 0,6 0,4 0,2

L/a 0

50

100 150 200 250 300 350 400

15



Design model






Very long welds



Design examples















Summary

16

Fillet Weld in Normal Shear

Two Fillet Welds in Parallel Shear

τ ΙΙ = 0

τ = F 2a l

σ⊥ = τ ⊥ = σR

From plane stress analysis is F 2a l

τ //

Topics

Reduction of design strength β Lw = 1,2 − 0,2 (Lw 150 a ) ≤ 1,0

0

τ //

Lw

Lw

1

τ//

13

Long welds 

Overloading of weld ends due to the different deformation of the connected elements

(

≤ f u β w γ Mw 3

)

2

Has to be satisfied

σ⊥ + 3 τ⊥ ≤ f u (βw γ Mw ) 2

2

After substitution

(σ 17

) (σ 2 ) = (β γ 2) 2

R

σR ≤ f u

2 +3 w

2

R

Mw

2 σR 2

≤ f u (βw γ Mw ) 18

Vl

Flange - Web Weld

Connection of Cantilever V Sd = FSd.

Shear force

Welds are loaded by longitudinal shear force

τII = FSd 2 a h

Transferred by web fillets Bending moment

M

Sd

V l = V Sd S I where

= F Sd e

I

Centre of gravity, Iwe and cross section modulus W we Wwe,1 and stress is

For weld at lower flange cross section modulus

σ ⊥1 = τ ⊥1 = (M Sd

Bases of design



Fillet weld

Maximum stress is at the point of maximum shear force

19



Design model






Very long welds



Worked Examples















Summary

In EN 1993-1-8 Chapter 4.10

Connection to plate deformed out of its plate

21

22

Effective Width 

20

Effective Width of Welded Beam-to-Column Connection



Unstiffened column flanges

a

τ II = V l 2 a ≤ f u β w γ Mw 3

)

2 W we ,2



moment of inertia

Shear stress

Topics 

shear force

Sd

This longitudinal force is carried by two welds effectiv e thickness

)

2 W we ,1

For upper weld on flange is

σ ⊥2 = τ ⊥2 = (M Sd

V

S Static moment of flange to neutral axis

Transferred by the shape of .weld

Effective Width t fb

 

beff = t wc + 2 s + 7 t fc

Unstiffened column flanges In EN1993-1-8 Clause 6.2.4.4

F t ,fc ,Rd = (t wc + 2 s + 7 k t fc )

⎛ t 2 ⎞ ⎛ f yc ⎞ beff = t wc + 2 s + 7 ⎜ fc ⎟ ⎜ ⎟ ⎜ t fb ⎟ ⎜ f yb ⎟ ⎝ ⎠ ⎝ ⎠ t wc t fc t fb s

VSd

r c t fc

t fb f yb γ M 0

⎛ f yc t fc ⎞ ⎟ ⎜ f yb t fb ; 1⎟ ⎝ ⎠

k = min ⎜

beff

t wc

σ

thickness of column web thickness of column flange thickness of beam flange equal to fillet radius r c for hot rolled column sections 23

t wc t fc t fb s

is thickness of column web thickness of column flange thickness of beam flange is equal to fillet radius r c for hot rolled column sections

24

Weld Design for Full Resistance of Connecting Members - Loading by Normal Force

Topics 

Bases of design



Fillet weld 

a > 0,7

Design model






Very long welds












Throat thickness of a fillet weld used in a hollow section joints






Summary

τ

V Sd

τ = V Sd / (t h)

≈ 0,85

σ w

f u / γ Mw

σ = F Sd / (t h) F Sd the acting design force f u plate design strength t the thinness of connecting plate b width of connecting plate full capacity of a plate the thickness S235: ( f y / γ M 0 ) t ( 235 / 1,10 ) t

f u / γ Mw

σ

F Sd

σ ⊥

= 0,7

360 / 1,25

t

= 0,52 t ≈ 0,5 t

h

t

f y /( 3 γ M 0 ) t f u / γ Mw

= 0,85

26

Weld Design or Full Resistance of Connecting Members

the design shear force in weld full capacity of a plate the thickness S235 τ t f w / γ Mw

τ ⊥

25

τ

a > 0,85

σ t

a > 0,7

Weld Design for Full Resistance of Connecting Members - Loading by Shear Force

V Sd

Not directly in code





Loading by shear force

∼ 0,5 t



Loading by normal force

∼ 0,4 t

235 /( 1,1∗ 3 ) t = 0,36 t ≅ 0,4 t 360 / 1,25

27

Topics 

Bases of design



Fillet weld 

Design model






Very long welds


















Summary

28

Welding in Cold-Formed Zones 

May be carried out within a length 5 t either side of a cold-formed zone 



Cold-formed zones are normalized after cold-forming but before welding r / t - ratio satisfy the relevant values: r/t ≥ 25 ≥ 10 ≥ 3,0 ≥ 2,0 ≥ 1,5

29

≥ 1,0

Maximum thickness (mm) Fully killed Aluminium-killed steel (Al ≥ 0,02 %) any any 24 12 10 6

30

V

Topics 

Bases of design



Fillet weld

Butt welds

1/2 V

Fully suply the cross-section



U



Design model






Very long welds


















Summary

For low quality is decreased design strength





Calculation as fillet weld

31

32

t anom


anom

a nom.1

a nom

c nom a nom.2

a = anom – 2 mm



Full penetration T joints

anom ,1 + anom ,2 t c nom ≤ 5 c nom ≤ 3 mm

t anom

a nom.1

anom

a nom

c nom a nom.2



≥ t

Partial penetration with an effective width

anom,1 + anom,2 < t .

a1 = anom,1 − 2 mm a2 = anom,2 − 2 mm

33

Topics 

Bases of design



Fillet weld 

Design model






Very long welds


















Summary

34

Summary 

Chapter 4 Welded connections

+ 

Rules for connection of open sections 



Rules for connection of hollow sections 

35

Component method Welded

36


Bolted Connections (Connections made with bolts, rivets or pins)

Lessons Connection Design according to EN 1993-1-8 Prof. František Wald


1

Scope of the Lecture  

     

     

Material

General Design resistance of individual fasteners 

2



Non-preloading bolts Single lap joints Bearing through packing Slotted holes Long joints Rivets Anchor bolts

Slip-resistant connections using 8.8 or 10.9 bolts Design for block tearing Lug angles Pin connections Injection bolts Summary

B Slip-resistant at serviceability

F v,Ed.ser ≤ F s,Rd,ser F v,Ed ≤ F v,Rd F v,Ed ≤ F b,Rd

C Slip-resistant at ultimate

F v,Ed ≤ F s,Rd F v,Ed ≤ F b,Rd F v,Ed ≤ N net,Rd

4.6

4.8

5.6

5.8

6.8

8.8

10.9

f yb (N/mm2)

240

320

300

400

480

640

900

f ub (N/mm2)

400

400

500

500

600

800

1000

3

4

Holes (ENV 1990)

Shear connections F v,Ed ≤ F v,Rd F v,Ed ≤ F b,Rd

Bolt class

Note: Bolts 12.9 are not allowed

Categories of Bolted Connections A Bearing type

Nominal values of the yield strength f yb and the ultimate tensile strength f ub for bolts



from 4.6 to 10.9 8.8 or 10.9

8.8 or 10.9

Tension connections F t,Ed ≤ F t,Rd F t,Ed ≤ Bp,Rd

from 4.6 to 10.9

E Preloaded

F t,Ed ≤ F t,Rd F t,Ed ≤ Bp,Rd

8.8 or 10.9



+1 mm for M 12



+2 mm for M 16 up M 24



+3 mm for M 27 and bigger



Extra large With loose 3 mm (M12) up 8 mm (M27)



Slotted (elongated)



D Non-preloaded

Normal

Accurate – flushed bolts 

5

for bolt M20 must be the clearance Δd < 0 , 3 m m 6

Positioning of Holes for Bolts and Rivets

Maximum Values for Spacings p1

e1

Minimum values for spacings





e2

Edge and end distances are unlimited, except : 

p2

End distance e1

1,2 d 0

Edge distance e2

1,2 d 0

Distance in slotted holes e3

1,5 d 0

Distance in slotted holes e4

1,5 d 0

Spacing p1

2,2 d 0

Spacing p2

2,4 d 0



for compression members in order to avoid local buckling and to prevent corrosion in exposed members and; for exposed tension members to prevent corrosion.

7

Local Buckling of Plate

Staggered Rows

in compression between the fasteners: 



minimum line spacing of p2 = 1,2d 0

need not to be checked if p1 / t is smaller than 9 ε ε =



8

235 / f y

according to EN 1993-1-1 using 0,6 p1 as buckling length t thickness of the thinner outer connected part 9

Resistance in Shear in One Shear Plane


General Design resistance of individual fasteners       

     

Plane of shear is going through threads of bolt: For classes 4.6 a 5.6



10

Fv ,Rd = (0,6 f ub A s ) γ M2 For classes 8.8 a 10.9 Fv , Rd = (0,5 f ub A s ) γ M2

A s Core area of cross section of bolt f ub Ultimate strength of bolt

γ M2 Partial safety factor of bolt 11

12

d 0

Resistance in Shear in One Shear Plane

Resistance in Bearing Fb,. Rd = (2 ,5 α f u d t ) γ M2

Plane of shear is going through shaft of bolt

Fv , Rd = (0,6 f ub A ) γ M2

A

d e 1

p 1

where α is minimum from formulas

e1 3 d 0 ; p1 3 d 0 - 1 4 ; f ub f u ; 1,0

Full area of cross section of bolt

f ub Ultimate strength of bolt

t

minimum thickness in one direction

γ M2 Partial safety factor of bolt

d

diameter of bolt

F b.Sd

d0 diameter of hole f ub strength of bolt f u strength of material

13

Resistance in Bearing

(0,8 in oversized holes)

14

Bearing of Plate and Bolt

In oversized holes reduction 0,8



Inner bolt



Outer bolt

Load on a bolt is not parallel to the edge, the bearing resistance may be verified separately for the bolt load components parallel and normal to the end R 10

20

30 e 1 40 p 1 60 e 1 40 t w 5,6

IPE 200 L 140

P 10 - 140 x 100

VSd = 110 kN

M 20 - 5.6

t p 10

10

50

4 4

10 15

16

Bearing Resistance of Bolt Group p 1 

For the holes 2: α =



e1 1,2 d 0 = = 0,4 3 d 0 3 d 0

α =

p1 3 d 0

− 0,25 =

F

Holes 1

3 d 0 3 d 0

e1 = 1,2 d 0

F

For the holes 1:

Tensile Resistance

e1

p 1 = 3 d 0

Holes 2

− 0,25 = 1 − 0,25 = 0,75

1)Total bearing resistance is based on direct summarising 2,5 d t f u 2,5 d t f u 2,5 d t f u = (2 ⋅ 0,4 + 2 ⋅ 0,75)⋅ = 2,3 ⋅ F b ,Rd = (∑α ) γ M 2

γ M 2

γ M 2

2)Total bearing resistance is based on smallest of the individual resistances 2,5 d t f u 2,5 d t f u 2,5 d t f u = (2 ⋅ 0,4 + 2 ⋅ 0,40)⋅ = 1,6 ⋅17 F b .Rd = (∑α ) γ M 2

γ M 2

γ M 2

Ft,Rd = (k 2 f ub A s ) γ M2 A s

Area of core of bolt

γ Mb

Partial safety factor

f ub

Ultimate bolt strength

k 2 = 0,90 for regular bolt head k 2 = 0,63 for countersunk bolt 18

Punching Shear Resistance

Combined Shear and Tension Experimental tensile resistance / predicted tensile resistance

F t,exp F t 1,0

Bp,Rd = 0,6 π d m t p f u / γ M2

Treads in shear plane Shank in shear plane F v,S

t p plate thickness

F v,R

+

F t,S

1 ,4

1

F t,R

0,5

d m the mean of the across points and across flats dimensions of the bolt head or the nut, whichever is smaller d m =

0

d 1 + d 2 2

d 2

Owens G.W., Cheal D.B.: Structural Steelwork Connections, Butterworths, 1989.20

19

Single Lap Connection with One Bolt Reduction of bearing resistance

F b ,Rd ≤

Scope of the Lecture

1,5 f u d t γ M 2

 

General Design resistance of individual fasteners   

M 16 - 5.6 P5 - 60 x 840 F Sd

 

8



5





30 30

    

21

Shear and Bearing pass through Packing


22

60% of resistance in circular holes (force perpendicular to the long direction of the slot )

9 d 8 d + 3 t p

22

18

18

Force, F, kN

200 180

40 40 8 16 8

β p ≤ 1,0 β


Bearing Resistance in Slotted Holes

Reduction of bolt shear resistance

β p =

0,5

0

d w d m

d 1

Experimental shear resistance predicted tensile resistance F v,exp 1,0 F t

M 16

40 40 8 16 8 M 16

p

1,0

tp

0,5

Circular holes, (test 1c-16-1-d+2)

160 140 120 100

10 35 50 25

10 35 50 25

110

110

Slotted holes, (test 5c-16-1-d+2,5)

80 60 40 20

Displacement , mm

0 0

0

0,3 d

1,0 d

1,5 d

5

10

15

20

25

30

35

40

t p 23

24

45

Long Connection

Scope of the Lecture 

Reduction of shear resistance β Lf = 1 −

L j − 15d





200 d



β Lt ≤ 1,0

β Lt 1

 

β Lt ≥ 0,75

0,8 0,75 0,6

 

L j



0,4



0,2

 

0 0

15d

65d

L j

 

25

Rivet Connections 

General Design resistance of individual fasteners






Philosophy of design was used for bolts



General Design resistance of individual fasteners  

Bolts spacing's recommendations are coming from rivets

    

    

27

Anchor Bolts






when the anchor bolts act in shear 640 N/mm2



N/mm2

900

 

28

General Design resistance of individual fasteners    





The nominal yield strength does not exceed otherwis not more than

26


(class A)



Non-preloading bolts Single lap joints Bearing through packing Slotted holes Long connections Rivets Anchor bolts



For bolts with cut threads reduction by a factor of 0,85

 

    

29





30

Slip-resistant Connections using 8.8 or 10.9 Bolts

Friction Coefficient μ F p.Cd

Prestressing force





Tests 

F s.Rd 

Fs,. Rd = (k s n μ γ M3,ser ) F p,Cd F p,Cd is design prestressing force of bolt

EN 14399-2:2002 High strength structural bolting for preloading Part 2 : Suitability Test for Preloading

Table for class of friction surfaces 

With painted surface treatments a loss of pre-load may occur over time. Class of friction surfaces

(= 0,7 f ub A s),

Slip factor µ

A blasted, metal spraying (EN 1090)

0,5

μ

friction coefficient

B blasted (EN 1090)

0,4

n

number of friction planes

C cleaned (EN 1090)

0,3

D cleaned (EN 1090)

0,2

ks

coefficient corresponding to clearance of hole 31

Hole Size Coefficient k s Description

Combined Tension and Shear k s

Normal holes

1,0

Oversized holes or short slotted holes with the axis of the slot perpendicular to the direction of load transfer

0,85

Long slotted holes with the axis of the slot perpendicular to the direction of load transfer

0,7

Short slotted holes with the axis of the slot parallel to the direction of load transfer

0,76

Long slotted holes with the axis of the slot parallel to the direction of load transfer

0,63



     

     

γ M 2 Δ F b

bolt preload F p

F b total bolt force

Δ F

F t external tensile force

δ p,ext δ b elongation of the bolt δ b,ext

δ p plate shortening

34

Block Tearing 



k s n μ ( F p ,C − 0,8 F t ,Ed )

33


F s,Rd =

F


32

Block tearing consists of failure in shear at the row of bolts along the shear face of the hole group accompanied by tensile rupture along the line of bolt holes on the tension face of the bolt group.

N Ed

N Ed

N Ed

35

36 N Ed

Test

FE Model

Rupture





Orbison J.G., Wagner M. E., Fri tz W.P.: Tension plane behavior in single-row bolted connections subject to block shear, Journal of 37 Constructional Steel Research, 49, 1999, s. 225 – 239.

Design Model

Topkaya C.: A finite element parametric study on block shear failure of steel tension members, Journal of Constructional Steel Research, 60 , 2004, s. 1615 – 1635, ISSN 0143-974X. 38

Worked Example - Angle P10; 1.4401



Symmetric bolt group subject to concentric loading

35

70 40

V eff,1,Rd = f u Ant / γ M2 + (1/√3) f y Anv / γ M0

240 100

35 25

70

L - 100 x 100 10 materiál 1.4401 30 + 7 x 30 +30

8 x M16; 70

60

Ant net area subjected to tension

240

Anv net area subjected to shear

In plate (staggered rows) V eff,1,Rd =



Eccentric loading

V eff,2,Rd = 39

Reduction of bearing resistance

d

e 2

t

F b ,Rd ≤

N u .Rd =

+

γ M2

1

f y

3

Anv γ M0

= =

0,5 × 530× (35 − 2 × 9) ×10 1,25 ×103

+

1 3

× 220×

(2 × 240− 6 ×18 − 2 ×9) ×10 1,1×103

= 72 + 409 = 481kN

In angle (staggered rows)

V eff,2,Rd = 0,5 f u Ant / γ M2 + (1/√3) f y Anv / γ M0

Single Lap Connection

f u Ant

0,5 f u,p Ant

+

γ M2

1 3

f y,p

Anv

= =

0,5 × 530× (60 − 189) ×10

γ M0

1,25×103

+

1 3

× 220×

(240− 3 ×18 − 9)×10 = 70 + 204 = 274kN 1,1×103

40

Single Lap Connection

1,5 f u d t γ M 2

p 1 N u .Rd =

2 ,0 ( e 2 − 0 ,5 d 0 ) t f u

γ M 2

2,50 d0 ≤ 5d ≥

p 1

γ M 2

p 1

β 2 Anet f u

p 1 N u .Rd =

p 1

β 3 Anet f u

p 1

γ M 2

Reduction factors Pitch p1

41

2 bolts β 2

0,4

0,7

3 and more bolts β 3

0,5

0,7 42

Worked Example – Fin Plate

Worked Example – Fin Plate, Shear Resistance

3 x M20, 8.8 P10 - 230 x 110 meteriál S235

HEA 200 S235

10

35

80

45 70

70

IPE 300 S235

45

230 70

70

70 45

230 70 V

Sd

50 50

45

= 100 kN

In beam web

5 50 50 60

V Rd,11 =

0 ,5 f u,b1 Ant γ M2

+

1 3

f y,b1

Anv γ M0

=

0,5 × 360 × 276 ,9 1 1171,5 + × 235 × = 199 kN 1,25 1,0 3

43

44


Worked Example – Fin Plate, Tying Resistance

 


45



70

70

70

70

  

45



50



50  

In beam web N Rd,u,6 =

f u,b1 Ant γ M,u



+

1 3

f y,b1

Anv γ M0

=

360 × 681,6 1 553 ,8 + × 235 × = 298 kN 1,1 1,0 3 45

Lug Angles

  


46


General Design resistance of individual fasteners    

1. The lug angle to transmit a force 1,2 times the force in the outstand of the angle connected. 2. The fasteners connecting the lug angle to the outstand of the angle member should be designed to transmit a force 1,4 times the force in the outstand of the angle member. 3. The connection of a lug angle to a gusset plate or other supporting part should terminate at the end of the member connected. 4. The connection of the lug angle to the member should run from the end of the member to a point beyond the direct connection of the member to the gusset or other supporting part. 47


  

     



48

Design of Pin

Pin Connections 

Analysis





As bolt (shear, bearing)



As beam (bending)



Given thickness t

Combination of shear and bending

a≥



d = 30

F Ed γ M 0 2 t f y

+

2 d 0 3

: c ≥

F Ed γ M 0 2 t f y

+

d 0 3

Given geometry

F Sd d 3 = 20

t 1

t 1 = 10

t 2 c

t 1 c

t 1 = 10

c =1

c =1 t 2 = 18

F Ed γ M 0

t ≥ 0,7

M Sd

f y

49

Analysis of Pin - Shear

50

Analysis of Pin - Bending Resistance of pin in bending

Resistance of one shear area of pin in shear Fv . Rd = (0,6 A f up ) γ Mp ≥ Fv . Sd = 0,5 FSd

M

Rd

= (0,8 W el A f yp ) γ Mp ≥ M Sd = (FSd 8 ) (t + 4 c + 2 t 1 )

F Sd

F Sd f up

applied force strength of pin

γMp = 1,45

partial safety material factor

A

: d 0 ≤ 2,5 t

applied force

f yp

yield point of pin

γMp = 1,45


A

Cross sectional area of pin

t 1

cross sectional area of pin

W el = π d 3 32 cross sectional elastic modulus of pin

t 2 c

M Sd

51

Analysis of Pin – Combination of Bending and Shear Stresses due to bending and shear:

(MSd

2

t 1 c

52

Analysis of Pin - Bearing Bearing stress of plate and pin

(

2

M Rd ) + (Fv ,Sd Fv , Rd ) ≤ 1

t 1

Fb, Rd = 1,5 t d f y

t 2 c

t 1 c

)γ

Mp

pro f yp ≥ f y a 2 t 1 ≥ t

f y

yield point of plates

f yp

yield point of pin

γMp = 1,45


M Sd 53

54

Analysis of Pin - Serviceability


Replaceable pin the contact bearing stress should satisfy σ h,Ed ≤ f h,Rd



σ h,Ed = 0,591

 



E F Ed ,ser ( d 0 − d )

 

d 2 t

 

f h,Ed = 2,5 f y / γ M6,ser d



the diameter of the pin;

d 0

General Design resistance of individual fasteners





the diameter of the pin hole;



F Ed,ser the design value of the force to be transferred in bearing, under the characteristic load combination for serviceability limit states

   

55

Injection Bolts



Bearing Strength of an Injection Bolt β σ2

β σ2

t2

σ1 σ2

t1 t2

F b,Rd,resin =

1,33 1,0

σ1

σ1 1.0



σ2 2.0

t1/ t2

Bolts of class 8.8 or 10.9 



The design ultimate shear load of any bolt in a Category A Preloaded injection bolts should be used for Category B and C connections 57


     

     

1

σ2

γ M 4

t2 t1 t2

1,33 1,0

σ1

σ1

σ2

ß f b,resin t b, resin k t

coefficient depending of the thickness ratio1.0 2.0 t / t bearing strength of the resin effective bearing thickness of the resin 1,0 for serviceability limit state 1,2 for ultimate limit state k s 1,0 for holes with normal clearances or (1,0 - 0,1 m), for oversized holes; m the difference (in mm) between the normal and oversized hole dimensions 58



1

Connections made with bolts, rivets or pins in Chapter 3 of EN 1993-1-8



k t k s d t b ,re sin β σf b ,re sin

Summary


56



Non-preloaded bolts



Preloaded bolts – preload (0,7 f ub)





59

Injection bolts (replacement of rivets; bolts 8.8 and 10.9) Pins (including serviceability)

60

2


Basics of structural joints (Structural Joints Connecting Open Sections)

Lessons Connection Design according to EN 1993-1-8 Prof. František Wald


1

2

Different Approaches

Scope of the Lecture 

General



Experimentation



Component method



Curve fitting



Basic components



Finite element analysis



Simplified analytical models – Component Method

 Assembly 

Resistance



Stiffness



Rotation capacity

M

Experiment

1



M-N interaction



Summary

Rotational stiffness



Moment resistance



Rotation capacity Joint resistance M j,Rd Elastic limit 2/3 M j,Rd

hb

M

+ C3 ( kM)3 + C5 ( kM )5

ta φ

3

Moment-Rotation Characteristic 

lt

Function φ = C1( kM)


M, moment, kNm Initial stiffness S j,ini



General



Component method



Basic components

 Assembly

Experimental curve Design curve

Rotation,φ , mrad Deformation capacity φ j,Cd

4

5



Resistance



Stiffness



Rotation capacity



M-N interaction



Summary

6

Procedure

Rotational Capacity



Decomposition of joint



Component description



Joint assembly

M

Bending moment, kNm

Experimental curve

Column web in tension

Bilinear model

Connection

M j.Rd

Plastic rotational capacity

Components in tension

φ pl

Components in compression



Classification

Web panel in shear



Representation



Modelling in analyses

Column web in compression Joint

Rotational capacity of joint 0

φ el

φ u

φ Cd

φ

Rotation, mrad

7

Decomposition of Joint

8

Background References 

Zoetemeijer P.: Summary of the research on bolted beam-to-column connections, TU-Delft report 26-6-90-2, Delft, 1990.



Zoetemeijer P.: Summary of the Research on B olted Beam-to-Column Connections (period 1978 - 1983), Ref. No. 6-85-M, Steven Laboratory, Delft, 1983.



Zoetemeijer P.: Proposal for Standardisation of Extended End Plate Connectio n based on Test results Test and Analysi s, Ref. No. 6-83-23, Steven Laboratory, Delft, 1983.

  

 Unstiffened column web in shear  Unstiffened column web in compression





 Beam flange in compression  Column flange in bending  Bolt row in tension  End plate in bending  Unstiffened column web in tension

9

Practical Application of the Component Method

10

Spring Models 

F

 Design tables  

Parallel configuration 1

Green book Blue book

2 2

1

Fu = F1.u + F2.u k = k1 + k2

 Computer programs



Serial configuration

d

1

F

 Simplified

δ = min (δ 1; δ 2)

2

1

hand calculation

Fu = min (F1.u; F2.u) 1 / k = 1 / k 1 +1 / k2

2

δ = δ 1 + δ 2 . 11

d

12


General



Component method



Basic components

Description of Basic Components 

The structural properties of basic joint components are described in Chapter 6 of EN 1993-1-8.



e.g.

 Assembly

 



Resistance



Stiffness



Rotation capacity

V Ed



Column web panel in shear



Column web in transverse compression



Column web in transverse tension



Column flange in bending

V Ed

F t,Ed



End-plate in bending

M-N interaction



Flange cleat in bending

Summary

etc.

F t,Ed

F t,Ed F t,Ed

13

Bolts in Tension

F t,Ed

 Analytical model 

F c,Ed

14

F t,Ed

End-plate in Bending  Analytical model

Stiffness coefficient

δ b

=

kb kb 

Resistance, see bolts



Deformation capacity - britle

=

Ft ,Ed Lb



2 E As

δ p

Ft ,Ed

A =2,0 s E δ b Lb

= k10 =1,6

Stiffness coefficient

kp

As

=

=

Ft ,Ed m 3 3 E I Ft ,Ed Ft ,Ed 3 E I E δ p

=

E Ft ,Ed m 3

=

3

2 Leff ,ini t 3 12 m3

= 0,5

Leff ,ini t 3 m3

Leff.ini = 1,7 Leff

Lb

kp

= k 4 = k5 = k6 = 0,85

15

Leff t 3 m3

16

F t,Ed

End-Plate Resistance 

Failure Modes

By equivalent T-stub in tension



Mode 1 - Plate failure



Mode 2 - Plate and bolts failure



Mode 3 - Bolts failure

F n

m t B



L eff 2

B

Deformation capacity - ductile 17

18

Bolt head / washer size influence F/2

Effective Length

F/2

F/2

F/2

Q ϕ



Q

Mode 1 only

n

 Q

F/4

F/4

Q/2

Q/2

F/2 F/2

u

n

F/4

F/4

Q/2

Q/2

 Another failure  

ϕ

m

Single bolt Bolt group

Q

C

C

19

Circular Failure

20

Bolt in Corner

⇒ F

F

F

F

F



ϕ

2 r

r=m

Virtual work on cone deformation

r=n

ϕ /2

= 2 π m

r´

δ

x

1,4

α = 8

2p

5,5

4,75

4,45

1,2

0,8 0,6

=

λ 1 =

ϕ /2 ϕ

λ 2

1,0

In EN 1993-1-8 graph only λ 2

α α

r

= α m

Leff ,op

δ

Leff ,cp

Single bolt Bolt group

dw

ϕ



Circular failure 

ϕ

u

m

dw

Q



Q

m2 m+e m m+e

ϕ /2

0,4 0,2 0,0 0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9

α α

α

21

Bolt at Oversize

22

T stub Position e

e mx

mx Weld w e mx

e mx

bp Yield lines

23

24

λ 1

Column Column Flange Flange with Backing Backing Plates Plates

Flange Flange Cleat in Bending Bending  As equivalent T-stub flange

e bp bp



Increase Increase of resista resistance nce Mode 1 only

FT,1,Rd

=

4M pl ,1,Rd

h bp bp e bp bp

+ 2M bp ,Rd m

M pl,1,Rd

= 0,25Σl eff ,1tf 2 f y / γ M 0

M bp,Rd

= 0,25Σl eff ,1t bp 2f y ,bp / γ M 0 25

Influence Influence of Gap g

Another Another Componen Components ts

0,4 ta

≤



g > 0,4 ta emin m 0,8 r a

r a

g ≤0,4 t

26

g >0,4 t

ℓeff

= 0,5b 0,5ba

see EN 1993-1-8 1993-1-8

emin m 0,5 t a

r a

a

Effective Effective length length



a

b a 27


General



Component method



Basic components

Design Resistance 

 Assembly 

Resistance



Stiffness



Rotation capacity



M-N interaction



Summary

28

Welded Welded connection connection

z

Ft,Rd

M j,Rd

Fc,Rd

M j ,Rd =Ft ,Rd z

29

30

Design Resistance 

Simpli Simplifie fiedd Lever Lever Arm

Bote Botedd conn connec ectition on – one one bolt bolt row row Ft.Rd

Ft.Rd z

z

Fc.Rd

M j ,Rd

=

∑F

i ti ,Rd

z

z

z

z

z

Fc.Rd

zi

31

More Bolt Bolt Rows - Firs Bolt Bolt Row (start from top) Limits by shear and compressed part

Resistence of first bolt row

Colum web in shear

Column web in compression

F

t1.Rd

t1.Rd

Column flange in bending

t1.Rd


F



F

t1.Rd

F

Beam flange in compression

t1.Rd

F

F

t1.Rd

t1.Rd

F

t2.Rd

F

F

t2.Rd

F

t2.Rd

t2.Rd


F

t2.Rd

End plate in bending

F

t2.Rd

Resistance of both bobt bobt rows

Column flange in bending F

t1.Rd

F

t2.Rd

F

t2.Rd

Column web in tension F

t1.Rd

F

t2.Rd

34


F

t2.Rd

F t3.Rd

F t3.Rd



General



Component method



Basic components

t1.Rd

F

F

F

F t3.Rd

F t3.Rd

F t3.Rd

t2.Rd

Column flange in bending,

Column web in compression

F


F

t1.Rd

Resistance of second bolt row t1.Rd

More More Bolt Bolt Rows Rows - Thir Thirdd Bot Bot Row Row Taking into account bolt rows groups Etc.

Colum web in shear

F

t1.Rd

33



Limit By shear and compressed part

End plate in bending

F

t1.Rd

More More Bolt Bolt Rows Rows – Seco Second nd Bolt Bolt Row Row

Beam flange in compression

F

F

32

t2.Rd

 Assembly

t2.Rd

F

F

F t3.Rd

F t3.Rd

t2.Rd

t2.Rd

Part in compression F

t1.Rd

t1.Rd

F

F t3.Rd

F t3.Rd

t2.Rd

Part in tension

F

F

t2.Rd

35



Resistance



Stiffness



Rotation capacity



M-N interaction



Summary

36

φ

Rotationa Rotationall Stiffness Stiffness Rotatinal Rotatinal stiffness stiffness

S j = M / φ δ i

Deformatio Deformationn or a component component

Shape Shape Stiffn Stiffness ess Ratio Ratio Factor Factor 

=

∑δ

Joint resistance M j,Rd

φ j

=

z

Elastic limit 2/3 M j,Rd

Joint Joint with with more more springs springs S j .ini

=

M j φ j

=

Fi z

∑δ

=

i

z

i

Fi z 2 Fi E

∑

1 ki

=

E z2 1 ki

→

∑

E z2 1 μ ki

 



 

j,

Initial stiffness S

ini

Design curve Shape by stiffness ratio factor Deformation capacity φ j,Cd Rotation,φ , mrad

37

38

Equivalent stiffness

δ

k eq z1 z z 2

M j



S j ,ini

∑

More Components 

ψ

⎛ M ⎞ μ = = ⎜⎜ κ Sd ⎟⎟ ≥1 S j ⎝ M j ,Rd ⎠ M, moment, kNm

Fi ki E

i

Rotation Rotation in joint

From From curve curve fittin fittingg

φ 1

φ 2  

k eff =

φ 3

    

=

∑k



Lever Lever arm

zi

z 1

∑ k1 i

i

   

eff ,i

i

z1

∑k z= ∑k

eff ,i z i

2

z4

i

eff ,i z i

i

39


40

Rotation Rotation Capacity Capacity



General



For platic platic global global analys analyses es



Component method



For For basi basicc safe safety ty



Basic components

M M j.Rd

 Assembly 

Resistance



Stiffness



Plate in bending



Rotation capacity



Column web in shear shear



M-N interaction



Summary

 41

φ Cd Cd

Ductile Ductile components components



0,0

φ el

φ u

φ Cd Cd

φ

Brittle Brittle components components 

Bots, welds

42

Upper Limits for Material In

the US standard only

In EN 1993-1-8 

F Brittle

Deem to satisfy criteria 

Ductile

Welded joints

φ CD ,min = 0,015 Unstiffned  Unstiffned in tension + Stiffened in compression + No shear influece 

δ δ Cd,1

φ Cd ,min

δ Cd,2

F

= 0,025 hc / hb

Ductile



Boted joints

Brittle



Plate failure  End plate/column flange thickness

δ δ Cd,1

t ≤ 0,36 d f ub / f y

δ 43Cd,2


44

M-N Interaction



General



For most portal frame connections (pitched rafters)



Component method



In EN 1993-1-8



Basic components

 Assembly 

Resistance



Stiffness



Rotation capacity



M-N interaction



Summary



Limit 5% of normal force resistance of connected element



Linear interaction



NSd N j ,Rd

+

MSd M j ,Rd

≤1

Component method

45

Example

VSd

46

Application of EN 1993-1-8 Procedure

M Sd NSd

N Sd M Sd 1 N j ,Rd M j ,Rd

Normal force, kN





Normal force





N j,t,M=0,Rd



N j,t,M,Rd Linear interaction

5 % error

Linear interaction 

 Moment,



kNm









M j.c.N

F1,t

 F2,c et Component method







Moment

M j.t.N



Linear interaction 

et

N j,t,M,Rd

Component method 

F3,t F2,t

N j,c,M,Rd

N j,c,M=0,Rd 47

N j,c,M,Rd





F1,c

48

Component Method - Resistance

Stiffness 

Centre of the part in tension F t.Rd

Simplification to two springs 

Bolts



Compressed part – in centre of flage

zt M Sd

N Sd

z

Fc.t.Rd

Ft.Rd

Centre of the part in compression zc

NSd z

MSd

Neutral axis

MSd

zc

F c.Rd

Active part

Fc.Rd

 As

zt

NSd

z

c.t

z z

c.b

Fc.b.Rd

Bolts and compressed part

Two compressed parts

for base plates 49

50

M - φ Diagram Praha Test

Evaluation on Tests

Moment, kNm

Normal force, kN

30

200 Test SN 1500

100

-10

20

10

0 0

Moment, kNm

Interaction -200

Prediction by component method

20 Prediction of resistance by interaction

15

SN 1000

-100

Test SN 1500

25

10

Component method

5 Rotation, rad 0 0

0,01

0,02

0,03

0,04

51

52

M - φ Diagram Coimbra Test

Evaluation on Coimbra Tests

Moment, kNm

Normal force, kN 800

Component method Interaction

400 0 0

-50

50 -400

Experiments EE7 EE6 EE1 EE2 EE3 EE4 EE5

Test EE7

120 Prediction by component method

100

Moment, kNm

80

Prediction of resistance by interaction

60 40 20 Rotation, rad 0 0 53

0,01

0,02

0,03

0,04

0,05

0,06 54


Design of Simple Connections (of Open Sections) Lessons Connection Design according to EN 1993-1-8 Prof. František Wald

Introduction Bases of design according to EN 1993-1-8 Welded connections Bolted connections Basicsof structural joints Design of simple connections Column bases Fire design of connections, EN 1993-1-2 Seismic design, EN 1998-1-1

1

SSEDTALecture 

2

List of Lessonsrelated to Connection Design 

New and Flexible Approach to Training for Engineers in Construction

Flow Charts    



Non-confli cting ComplementaryInformation  





Leson16 Design of Simple Joints

    



Access STEEL information tool on internet

  



Simple connections -fin plates Simple connections - end plates Column splices for both axial load & moment Column bases (axial load only) Design model for simple end plate connections A: Detailing guidance B: Shear resistance C: Tying resistance Design model for simple fin plate connections A: Detailing B: Shear resistance C: Tying resistance Design model for simple Column splices (non-bearing) Initial sizing for non-bearing splices Design model for simple Column bases - axially loaded

Passive examples     

Beamto beamfin plate connection Beamtocolumnend plateconnection Column splice(non-bearing) Column base,axially loaded Column splice(bearing)

3

4

5

6

Example – Fin Plate 

Flow chart


Subject to shear 1

1

3

1

3

4

2

2

2

1. Fin plate 2. Supported beam 3. Column 4. Supporting beam 7

8


Example – Fin Plate

Mode of failure - subject to shear



Bolts in shear

V Rd,1

Fin plate in bearing

V Rd,2

Fin plate in shear (gross section)

V Rd,3

Fin plate in shear (net section)

V Rd,4

Fin plate in shear (block shear)

V Rd,5

Fin plate in bending

V Rd,6

Fin plate in buckling (LTB)

V Rd,7

Beam web in bearing

V Rd,8

Beam web in shear (gross section)

V Rd,9

Beam web in shear (net section)

V Rd,10

Beam web in shear (block shear)

V Rd,11

Supporting column web or supporting beam web (punching shear)

V Rd,12 9

10


Ductility requirements not guided by bolt shear failure

Example – Fin Plate

Rotation capacity requirements



Subject to tying forces

1. Given rules in initial design Depth of supported beam h b1 (mm)

Fin plate thickness t p (mm)

Fin plate width b p (mm)

Horizontal gap g h (mm)

Beam edge distance e 2,b (mm)

Fin plate edge distance e 2 (mm)

h b1 ≤ 600

10

100

10

40

50

h b1 > 600

10

120

20

40

1

1

3

1

3

4

60 bp

or

gh

hp

g

v

2. Limit of hight and calculate required rotation ≤

hb

−

φ available

2t f,b1

−

2r

> φ required

e1,b

e1 a

p1

hp

p

1

e1 e 2 e 2,b z

11

2

2

2

1. Fin plate 2. Supported beam 3. Column 4. Supporting beam

he

12


Summary

Mode of failure– subject to tying



Bolts in shear

NRd,u,1

Fin plate in bearing

NRd,u,2

Fin plate in tension (block tearing)

NRd,u,3

Fin plate in tension (net section)

NRd,u,4

Beam web in bearing

NRd,u,5

Beam web in tension (block tearing)

NRd,u,6

Beam web in tension (net section)

NRd,u,7

Supporting column web in bending

NRd,u,8



Design of simple connections not described in EN 1993-1-8 Tables   



Green book UK Blue book Germany ECCS TC10 document (in preparation)

Access STEEL materials on internet

13

14


Introduction Bases of design according to EN 1993-1-8 Welded connections Bolted connections Basicsof structural joints Design of simple connections Column bases Fire design of connections, EN1993-1-2 Seismic design, EN 1998-1-1

Thank you for your attention

15

16

Simple Joints

Structural Steelwork Eurocodes



Design of Simple Joints

Frames are traditionally analysed assuming joints to be either: – Pinned. – Rigid.



However few joints meet these ideals.

1

2

Design Considerations of Joints

EC 3 Requirement 



Rigid Joints: – Expensive to fabricate and construct.



Real Pin Joints: – Also expensive



Simple Joints: – Need to be flexible

3

4

Joint Requirements

Joint Properties

 

EC3 states that: – “A nominally pinned connection shall be designed so that it cannot develop significant moments which might adversely affect members of the structure.”

Joints must: – Transfer actions. – Accept required rotations.

5

Joints have three principal properties: – 1. Strength: » able to transfer moments & forces. – 2. Stiffness: » have an appropriate slope on M - Ø curve. – 3.Deformability: » Have adequate rotation capacity.

6

Stiffness Requirement

Strength Requirement

S j,ini not greater than: 0,5 E Ib / Lb.



Depends upon the members connected.

where: S j,ini is the initial rotational stiffness of the connection. Ib is the second moment of area of the connected beam. Lb is the length of the connected beam.



Ensures that joint has only a small resistance compared to the connected members.



Remember that shear and any axial load must be transferred between members.

7

8

Maximum Moment Resistance

Rotation Capacity

Mpbisisfully fullyplastic plasticmoment momentofofresistance resistanceofofcolumn. beam. Mpc 

Joint must not fail as a consequence of any large rotations required.



Not sufficient to consider just the detail of the connection in initial state.

Mpc

Mpc Mpb

Mpb

Mpc

Mpc

If Mpb < 2Mpc then M j,Rd = 0.25Mpb

If Mpb > 2Mpc then M j,Rd = 0.25*2*Mpc

Figure 1: Maximum moment resistance requirement for simple joints

9

10

Effect of Gap Closure

Practicalities

φ

M



Contact between beam flange and column face

M

Many joints currently assumed to operate as simple joints transfer moments in excess of EC3 limits.



Resulting designs function satisfactorily.



Supported by extensive research.

φ Figure 2 : Effect of gap closure 11

12

Beam to Column Joints Example 1

Transfer of Forces



Joints likened to links in a chain.



Strength determined by weakest link.



Principal transfers by: – Welding. – Bolting. – Riveting,(occasionally ).

Top and seat cleats (major and minor axes

Seat and stability cleats (major and minor axes)

13

14


Single web cleat (major axis: bolted to beam and column) Welded fin plate: (minor axis: bolted to beam, welded to column.


Double web cleats (minor axis: Welded to beam, bolted to column). Tab plate: (major axis: welded to beam, bolted to column).

Shear plate (major axis)

Shear plate (major axis)

15

16

Typical Beam to Beam Joint

Simple Web Angle Connection

Supporting beam Supported beam Figure 4: Beam to beam connections

Single notched angle Double notched end plateconnection connection 2.1.2 Should any tying forces need to be considered ( as is the case in the U.K.NAD). Then the connection must also be checked for such action which will involve consideration of the following potential failure modes, remembering that it will often be necessary to combine the axial and the shear forces to obtain a resultant action. 17

18

Simple Web Angle Connection

Transfer of Forces



Shear force must be transferred to column.



This involves several steps: – Beam into bolts. – Bolts into angle. – Angle into bolts. – Bolts into column flange.

a1 Lv a3 a2





   

19

20

Transfer of Forces

Checks Needed for Tying Forces

Web of beam into bolts: – Block shear. Web of beam into bolts: – Bearing. Shear failure in bolts. Bearing and block shear in angle legs. Shear in bolts to column flange. Bearing in bolts to column flange.

    

21

22

Other Detailing Guidance

Summary

     

Block shear in beam web (amended failure zone). Bearing in bolts to beam web. Shear in bolts. Tensile capacity of web cleats. Tensile capacity of bolts to column face.

Minimum end distance. Minimum edge distance. Maximum end and edge distances. Minimum bolt spacing. Maximum bolt spacing.







23

The philosophy of simple joints in terms of idealised and real behaviour has been introduced. The concept of joints as an assemblage of components has been put forward. Requirements for strength, stiffness and rotation capacity have been described. Examples of practical details are provided.

24

List of Lessons at Seminar Column Bases Lessons Connection Design according to EN 1993-1-8 Prof. František Wald

1.

Introduction

2.

Bases of design according to EN 1993-1-8

3.

Welded connections

4.

Boltedconnections

5.

Basics of structural joints

6.

Design of simple connections

7.

Column bases

8.

Fire design of connections, EN 1993-1-2

9.

Seismic design, EN 1998-1-1

1


Basis of design Components



ENV 1993-1-1 – Annex L (1992)

– Base plate in bending and bolt in tension – Base plate and concrete in compression – Anchor bolt in shear 

Background Materials

Assembly

– Annex A2 – Design of Joints (1992, 1999) 

COST C1 - Semirigid connections (EU project, finished 1999)

– Resistance – Stiffness – Pre-design   

Classification Worked examples Summary

Fixing by Base Plate Base plate in bending and anchor bolts in tension

Component Method Baseplate and concrete in compression

Baseplate in bending anchor bolts in tension

Column web in compression Base plate in bending and concrete in compression

Anchor bolts in shear

Major components

Column flange and web in compression

Anchor bolt in shear



Base-plate in bending and anchor bolts in tension Column flange

– Base plate in bending and bolt in tension – Base plate in bending and concrete in compression – Anchor bolt in shear 

e

Assembly – Resistance – Stiffness – Pre-design

  

F

m

t l eff


Base plate

F

Contact of Edge of T stub

δ b = Θ p n m

n

δ b

Θ p Q=0

Q=0

3

Lb .lim

Embedded Anchor Bolt

=

< >

8 ,82m As 3

Leff t

Lb

Force, kN 180

L bf L L be

40

160 Experiment W13/98

140

b

d

Experiment W14/97

120

24 - 355 315

Prediction

5

P6 - 40 x 50 40

100 80

50

60

10

10 6

40

P10 - 95 x 95

5

20

Lbe ≅ 8 d

0 0

0,2

0,4

0,6

0,8

1

1,2

1,4

1,6 Deformation, mm

CEB documents for anchor bolts resistance

95

95

3

e

F / B t.Rd 1

Mode 2

Mode 3

m

n

0,8 F Rd.3

F Rd.1

F Rd.2 Bt.Rd

Bt.Rd

Bt.Rd

B Q

Mode 3

a)

b)

B t.Rd

B Q

Q

Q

Mode 1

Mode 1

0,6

Mode 1*

0,4

Mode 2

c)

0,2 F Rd.1*

Endplate – contact or no contact

0 0

Base plate – no contact

0,5

1

1,5

2 4

B

2,5

eff M pl.Rd

/

B

Force, kN

350

F Rd.1*

350 Force, kN

300

Resistance

300

Simplified prediction

250

W97-12

250 Experiment

200

m = 32 Complex calculation

150

B

∗

F Rd .1

=

B

Complex calculation m = 67

150

Simplified prediction

100

100

50

50

2 Leff M ´ pl . Rd

200

W97-02

Deformation, mm

0 0

2

4

6

8

Deformation, mm

0 0

2

4

6

8

m

Effective length of T stub

Stiffness

No prying 0 ,425 L eff t 3 k p = m 3 Prying accured 0 ,85 Leff t 3 k p = m 3

As k b = 2 ,0 Lb As k b = 1,6 Lb

e m

Prying occured 2 m 4 m 1 , 25 e 1 2

2 m

Leff ,1 min 1 ; Leff , 2

1

2

No prying 1

2 m 4 m 1 , 25 e

2

4 m

Leff ,1 min 1 ; Leff , 2

1

2

B t.Rd

e

w

e e x

Effective Length for Hollow Sections

m x

(not in EN 1993-1-8) a

b p

ac b (a)

Prying 1 = 4.m x+1,25 e x m x 2 = 2 = 0,5 b p 3 x + 0,625 e x 4 = 0,5 w + 2 m 5 = e + 2 m x + 0,625 e x m x 2 e 6 =

No prying

Leff ,1 min 1 ; 2 ; 3 ; 4 ; 5 ;

Leff ,1 min 1 ; 2 ; 3 ; 4 ; 5 ;

Leff , 2 min 1 ; 3 ; 4 ;

1 2 3 4 5 6

6

m

= 4.m x+1,25 e x = 4 m x = 0,5 b p = 0,5 w + 2 m x + 0,625 e x = e + 2 m x + 0,625 e x = 2 m x 4 e

Leff , 2 min 1 ; 3 ; 4 ;

5

Leff .5



= π m

 

=

Leff .4

=

b 2 a

m

2

=

Leff .3

eb

m ea

(a − a c )2 + (b − bc )2 2

=

ea

2

+ eb 2

8 e a eb

m

−

ea

2

+ eb 2

(a − a c )2 + (b − bc )2

L eff = min ( Leff .1 ; Leff .2 ; Leff .3 ; Leff .4 ; Leff .5 )

5

Base plate in bending and concrete in compression


Column flange

FSd

FRd c

Assembly

tw

c

t

L

– Resistance – Stiffness – Pre-design 

Leff .2

6

– Base plate in bending and bolt in tension – Base plate and concrete in compression – Anchor bolt in shear 

bc

m

Leff .1 = π m


b

Base plate


f j



Flexible base plate



3D behaviour – concrete in crushing

M

Concrete 3D Resistancein Crushing (the same as EN1992-1-1)

a1 a

c

c c

c

c

a r

c

t

Joint coefficient

Effective width

Effective width

k j =

a 1 b1 ab

⎧a + 2 a r ⎫ ⎪5 a ⎪ ⎪ ⎪ a 1 = min ⎨ ⎬ a h + ⎪ ⎪ ⎪⎩5b1 ⎪⎭

t h

b b r

a1

≥a

⎧b + 2 br ⎫ ⎪5 b ⎪ ⎪ ⎪ b1 = min ⎨ ⎬ b1 ≥ b ⎪b + h ⎪ ⎪⎩5 a 1 ⎪⎭

b1

c

Effective width

M′ = M

Elastic resistance ensuring small deformations, to unit length

1 M ′ = 1f j c 2 2 M ′ =2 f j c

Bending moment to unit length

1 1 f 2c 2 =112t 2 f f j c j = 6t f y y 22 6

Equivalent length of cantilever c Effective width

c=t

f y 3 γ Mc0=f jt

f y 3 γ M 0 f j

2

1 22 t f ydf yd 6

Comparison to FE simulation

Contact Area

Vertical deformation at the surface, mm

c

0,0

c

}

F

Vertical deformation along the block height top of the concrete block elastic deformation of the whole block

elastic deformation δ glob

local deformation under plate

c

A

Ap

0,1

deformation at the edge δ edge

predicted value

deformation at the axis δ axis

A eq

edge

c

c

axis

Vertical deformation, mm

foot of the concrete block 0

0,1

c

Stiffness F r

Comparison to Experiments a r

F tw

1600

E c

L

F

E c

1000

k c

E

a eq . el L

1 , 5 * 0 ,85 E

a eq.el = t w + 2,5 t

E c

a eq . el L

800

1 , 275 E

Prediction based on local and global deformation,

600

a eq.str = t w + 2 c = t w + 2 t

f y 3 f j

400 M 0

c fl

Prediction based on local deformation only

200 0

x

0

E I p

δ

0,1

0,2

0,3

0,4

0,5

0,6

0,7

0,8

0,9 Deformation, mm

Grout t t g


t g

t g



h

L

Experiment Concrete and grout Concrete

1200

ar

t

Calculated strength

1400

0 ,85 F r

Force, kN

1800

deformation of elastic hemisphere

E c A r

o

45



t g

– Base plate in bending and bolt in tension – Base plate in bending and concrete in compression – Anchor bolt in shear

o

45

β j = 2 / 3

f c.g ≥ 0,2 f c t g ≤ 0,2 min (a ; b) t g ≥ 0,2 min (a ; b)

lower nut

packings





  


Components in Shear

Anchor Bolt in Shear Fh

Resistance in tension

Fh

Reduce resistance in tension

δ h

Resistance in bending and shear δ h

0

5.6

4.6

F v .Rd =

0 ,375 f ub As

F v .Rd =

0 ,250 f ub As

Mb

Mb

Format as bolts in shear

Resistance


N Rd

Basis of design Components – Base plate in bending and bolt in tension – Base plate in bending and concrete in compression – Anchor bolt in shear



r b

 

M Rd

M 2, N 2



= Aeff f j − ∑ F t . Rd




N M=0


= ∑ F t . Rd r b + Aeff f j r c .

compression

Interaction diagram

Aeff f j r c

– Base plate in bending and bolt in tension – Base plate and concrete in compression – Anchor bolt in shear

M N=0

0

F t .Rd r b


F t.Rd

j

Plastic design –force equilibrium Complex shape of contact area

M

M Rd

f − ∑ F t . Rd = A f eff j

∑

M1 , N 1

tension

N Rd

N Rd = Aeff M f j Rd - = F F t .t Rd . Rd r b + Aeff f j r c .


N Rd

Aeff active part

r c

∑ F t.Rd




M Rd

N

  


History of Loading MRd

N Sd

Moment Non-proportional loading

M Sd c c

Non-proportional loading Proportional loading

Moment Proportional loading

Nonlinear part of the curve

N Rd

Normal force

0

φ

Anchor bolts in tension and one flange in compression

F t

= Aeff f k j −⎪⎨ ∑ F t . Rd t

⎪ ⎩

k c

k b

k c

k c


M Rd

S j.ini Rotation

0

k p

⎧

F c

e0 NSd

c

cc

c

c

z z c

z T

Column base resistance

Plastification of one component

c

M Rd min 1

FT . Rd z z c

F c . Rd z z t

; 1

M Sd / N Sd

M Sd / N Sd

Simplified contact area

Stiffness S j

M Sd / N Sd M Sd / N Sd

E z 2 1

k t

N Rd

c

80

c c

= Aeff f j − ∑ c F t . Rd

c

cc

c

∑

F r M / 2 Rd = MSd / N Sd r / 2 M Rd / N Sd M Sd / N Sd Simplified contact area 1

r

20

k c

M 20 - 10.9

t

= Aeff f j − ∑10F t . Rd Rotation, mrad

0

k c

Rd

15

N Rd

+ Aeff f j r c .

k b

M

60

0

k ⎧ p ⎪t . Rd b ⎨k t ⎪ ⎩

400 kN HE 160 B

20

40

2 ,7

1 ,5

t = 30 25

120 100

ki

z c k c z t k t k c

Moment, kNm

x c
M Sd / N Sd = konst.

5

10

15

M Rd


20

25

30

k c

Sensitivity study, base plate thickness

N Sd

Normal force, kN

M

Sd

3 000

Lever arm is changing by the activation of one bolt row Lever arm is changing by the activation of both bolt rows 40 Simplified prediction

M 24

t 30

Base plate thickness, t, mm 2 000

Components

HE 200 B

Force, kN

200

M pl.Rd h = 1 000

1 000

20 15

N Rd

F t . Rd = Aeff f Column j − ∑ resistance

0 1 600 420 590

200

M Rd 100


420

0

80

Base plate 0,5

200 E k c Force, kN

1 600

0

N Rd 40 = Aeff f j 20 Rd

M

0,5 Concrete , mm

Deformation,

Experiment W7-4.20-prop

60

100

Moment, kNm

Sensitivity study, baseplate thickness, resistance

Anchor bolt 0,5 Force, kN

100 E k p 590

0

Moment, kNm

E k b

100

Npl.Rd 30 25

Assembly

−Prediction ∑ F t . Rd

N HE 160 B t = 20 h = 500


0 0

Comparison to experiment

10

Rotation, mrad

M

Pre-design, stiffness


2

S j .ini .app =

E z t



20



M

M

Sd

N Rd

= Aeff f j − ∑ F t . Rd

M Rd



Sd



z



z

  

Lever arm

Classification


Non-Sway by Resistance

 According to stiffness

t = 12 mm a 1 = b1 = 280 mm a = b = 500 mm h = 1000 mm M 24 -420 S j,ini,pin = 7 100 kNm / rad

F cr.pin

β =

F cr,res

1

 Accuracy

0,9

5% in resistance and 10% in serviceability

S j,ini,pin

t = 40 mm a 1 = b1 = 420 mm a = b = 500 mm h = 1000 mm M 24 -420 S j,ini,stif = 74 800 kNm / r

0,8

S j,ini,stif 0,7

 Simillar to beam-to-column joints

0,6

_

0,0001

0,01

1,00

100,0

log S

2

o

pro

o

pro 0,5 < pro

o

0,5 o

S j,ini < 3,93

3,93

Sway Frames for Serviceability

0

S j,ini 7 (2

o

- 1) E I c / L c

S j,ini 48 E I c / L c

115 kN

y HE 200 B

1,0

1 , 36

0,6

S j,ini 12 E I c / L c.

S j,ini,pin

0,4

5m

S j,ini,stif

0,2

Asked stiffness for relative slenderness

0 0,0001

4m

HE 200 B

0,8

o

115 kN

5 kN

yS / yP

0,01

1

100

log S


Relative moment 1,0 Rigid connection 0,8 S j.ini.c.n 0,6



= 30 E Ic / L c

S j.ini.c.s

0,4 0,2 0



= 12 E Ic / Lc Semi-rigid connection

o


= 1,36

Hinge

0

0,1

0,2

0,3




Relative rotation,


In relative values   


c b c =200

Worked Example – Base plate

c

c tw=9 c a1 = 1600

M Sd

FSd

a = 420

a r = 590

HE 200 B M 24

t = 30 30

c c

t f =15 e a= 50

b r = 590

h c =200

e b = 90 b = 420

p = 240 h = 1000

b1 = 1600

b eff

t f =15 c c

r b = 160

e c = 60

r b r c

Contact area

Worked Example – Frame (sway) M j.Rd / M Ny.pl.Rd

1,0

F

Sd

0,8 S

0,6

j.ini.c.n

0,4

S

(for

= 12 E I c / L c

o

Sd

F

F

Sd

Sd

F

Sd

F

Sd

F

Sd

IPE 550

F

Sd

2

1,2 m

1 , 36 )

HE 340 B

0,2 0

Sd

2

= 30 E I c / L c

j.ini.c.s

F

F

HE 340 B 9 m

0

0,1

0,2

0,3

E I c / L c

Worked diagram 24 m

F y

F y

F y

F y 2

F y

F x

F y F x

F x F x F x 2 F x = 0,38 kN

F y F x

F y F x

F y = 23,00 kN

w

1

F y 2

F y

F y 2

F y

F y

F y

F y

Frame imperfections – by equivalent forces



Element imperfections – by stability check

F y 2

F x 2

N

N H φ

F y = 26,79 kN

w

2

w = 2,64 kN/m

F y

F y



1

w = 1,65 kN/m 2

First load combination

Second load combination

φ

Load combination

H φ N

N

Comparison 

Maximal moment in base plate kNm

Elastic design – connection stiffness, pre-design

z

S j .ini . b c

z

S j .ini . b b

E z 2 t

210 000 * 700 2 * 20

k f

8 , 5

E z 2 t

210 000 * 700 2 * 20

k f

6

242 100 kNm / rad

343 000 kNm / rad

Maximal moment in corner kNm

Maximal moment in rafter kNm

Vertical deformation of rafter mm

Horizontal sway of corner mm

0

337,85

318,10

113,68

73,70

108,20

290,13

307,62

109,80

27,43

214,09

305,90

274,73

95,54

19,42

3 2,5 2

S j .ini . cb

E z 2 t

210 000 * 400 2 * 30

k f

20

1,5

50 400 kNm / rad

1 0,5 0

z


Basis of design Components – Base plate in bending and bolt in tension – Base plate and concrete in compression – Anchor bolt in shear




  


Summary 

Component method Good accuracy



Worked examples –Savings by taking into account of stiffness (for serviceability only) –Hand calculation unusual


Fire Design of Connections Lessons Connection Design according to EN 1993-1-8 Prof. František Wald


1

2

Scope of the Lecture 

Structural fire design



Temperature of connections



Connectors at elevated temperature



Component method



Structural integrity



Summary

Structural Fire Design – Procedure of Design 

Thermal analyses of fire compartment or local fire (EN 1991-1-1)



Transfer of heat into the structure (EN 199x-1-2)



Mechanical loading at fire situation (EN 1990, EN 1991-1-x)



Mechanical modelling of structure at elevated temperature (EN 199x-1-2)

3

Connections under Fire

EN 1993-1-2 Approaches



Steel looses with temperature strength and stiffness



Steel structures expand when heated and contract on cooling



4

Temperature within the connections is lower compare to connecting steel members



Fire protection is applied to the member and its connections 



Component approach in EN 1993-1-8 together with a method for calculation the behaviour of welds and bolts at elevated temperature 

5

Rules based to protect as members

Connection moment, shear and axial capacity can be evaluated at elevated temperature 6


Analytical Models of Heat Transfer 1. Section factor ( Am /V) method simmilar as for members Am /V surface/volume ratio












Component method






Summary

2. Based on the temperature of the beam lower flange Concrete slab

h h h

h ≤ 400 mm 0,62 θ 0

h > 400 mm

0,75 θ 0

0,88 θ 0

0,88 θ 0

0,88 θ 0

0,70 θ 0

7

Accuracy Demonstration on 7th Large Scale Fire Experiments on Steel Frame A

B

9000

C

9000

E

D

9000

9000



 Temperatures in elements and connections



9000

 Internal forces in the connections



 Behaviour of the composite slab



2

6000 1

January 16. 2003

Motivation



3

Fire Test

F

9000

4

6000

8





Fire Compartment for Structural Integrity Fire Test, January 16, 2003

9

10

Fire Compartment Instrumentation

Interier

Exterier, Fire load 11

     

148 thermocouples 57 low temperature strain gauges 10 high temperature strain gauges 37 deformations 10 video cameras 2 thermo-imaging cameras

12

Moderate Fire

No Collapse Reached

Maximal temperature 1108 °C in 55 min

Deflections over 1000 mm; residual deflections 925 mm

13

14

Fin Plate Connection before the Experiment

Instrumentation

West view

D

E

C442 C443

Walls C454 - 462

2

C486 - 488

G521

C463 - 471 G525

G522

G526 C441 - 449

C447 C444 C448 C445

C441

C472 - 475

C449

C446

C475 - 479 G529

G533

120 D1/2-E1/2

G534

North view

G530 C450 - 453

C483 - 485

C483 C484

G523

G527

G531

FIRE COMPARTMENT

C485

G535 N G536

D2

E2

1

G524

G528

C480 - 482

G532

Window

Fin plate connection

Thermocouples at elements and connections, numbered Cijk Thermocouples in compartment 300 mm below ceiling, numbered Gijk

Fire compartment

DE1/2

West view C450 4th bolt row C451 3rd bolt row C4522nd bolt row C453 1st bolt row

N D1

E1

120 E1/2-D1/2

15

t = 26 min.

t = t0t +t==028’ 2 6hm28’ in

θcon,ø = 275 °C

980, 0°C

16

T= 330 °C = 330 275=°C °C θθ con,ø con,ø con,ø

980,0°C

In 26 min of fire is temperature of the structure under 400°C 800

600

600

Gas temperature

Gas temperature Heating θ ,°C

400

1000

400, 0°C

600 0 0

800

Time 30

60

90

1000

0 0

t, min

17

Heating

θ ,°C

400 400,0°C

600

Time 30

60

90

t,min

18

t = t0 +t =042 h min 42’

Tcon,ø 645 °C = 645=°C θcon,ø

t = t0 +t =044 h min 44’


980,0°C

980,0°C

Buckling of beam lower flange

1000

Buckling of beam lower flange

θ ,°C

800

800

600

600

400 400,0°C

600 0 0

30

60

90

1000

θ ,°C

400 400,0°C

600 0 0

t,min

30

60

90

t,min

25

t = t0 +t =046 h min 46’

26


t = t0 +t =048 h min 48’


980,0°C

1000

θ ,°C

980,0°C

800

800

600

600

400 400,0°C

600 0 0

30

60

90

1000

θ ,°C

400 400,0°C

600 0 0

t,min

30

60

90

t,min

27

t = t0 +t =050 h min 50’

28


t = t0 +t =052 h min 52’

980,0°C

1000

θ ,°C

0 0

980,0°C

800

800

600

600

400 400,0°C

600

30

60

90

1000

29

θ ,°C

400 400,0°C

600 0 0

t,min


30

60

90

t,min

30

t = t0 +t =054 h min 54’


t = t0 +t =056 h min 56’

The maximal temperature of 1088 °C of secondary beam was reached by its lower flange in 57 min

980,0°C

Gastemperature θ ,°C Cooling

1000

30

60

90

800

600

600

400,0°C

Time

0 0

Gas temperature θ ,°C Cooling

400

1000

400,0°C

600

Time

0 0

t,min

30

60

90

t, min

31

t = t0 +t =058 h min 58’

32


t = t0 +t =160 h min 00’


980,0°C

Gas temperature Cooling θ ,°C

980,0°C

800

800

600

600

400

1000

400,0°C

600

30

60

0 0

34

800

800

600

600

1000

35

θ ,°C

400 400,0°C

600 0 0

t,min


980,0°C

400

90

t,min

980,0°C

400,0°C 60

90

t = t0 +t =164 h min 04’

θ ,°C

30

60


Maximal temperature of fin plate connection 908,3°C was reached in 63 min

600

Time 30

33

t = t0 +t =162 h min 02’

1000

400 400,0°C

0 0

t,min

90

Gastemperature Cooling θ ,°C

1000 600

Time

0 0

980,0°C

800

400

600


30

60

90

t,min

36

t = t0 +t =178 h min 18’


t = t0 +t =180 h min 20’


980,0°C

1000

θ ,°C

980,0°C

800

800

600

600

400 400,0°C

600 0 0

30

60

90

1000

θ ,°C

400 400,0°C

600 0 0

t,min

30

60

90

t,min

43

t = t0 +t =182 h min 22’

44


t = t0 +t =184 h min 24’


980,0°C

1000

980,0°C

800

800

600

600

400

θ ,°C

400,0°C

600 0 0

30

60

90

1000

θ ,°C

400 400,0°C

600 0 0

t,min

30

60

90

t,min

45

t = t0 +t =176 h min 26’

46


t = t0 +t =178 h 28’ min

980,0°C

1000

θ ,°C

0 0

980,0°C

800

800

600

600

400 400,0°C

600

30

60

90

1000

47

θ ,°C

400 400,0°C

600 0 0

t,min


30

60

90

t,min

48

Fin plate connection after the fire test

Temperature Differences Measured by Thermocouples

Measured temperature, °C D2

E2

D1

E1

Difference shown 1000 by the thermo imaging 800 camera 600 400

Fin plate, by 4th bolt

200

Beam, bottom flange

0 0

15

30

45

60

75

90

105

120

135

Time, min

Maximal temperature of fin plate by 4th bolt 908 °C in 63 min 67

Analytical Prediction Compared to Test Connection temperature, °C

68


Predicted from gas measured temp. based on "section factor"

1000 800

D2

E2

600 Predicted from beam bottom flange based on measured temp.

400

D1

E1

200 Measured












Component method






Summary

0 0

15

30

45

60

75

90

105

120

135

Time, min

Measured 908 °C in 63 min.; predicted 878 °C in 53 min 69

Bolts and Welds Properties at Elevated Temperature 

70

Bolt Resistance at Elevated Temperature

Factors k b,θ; k w,θ are used to describe the strength reduction



Marked loss of strength between 300 and 700ºC

1



Shear resistance of bolts in fire

Bolt

0,9

F v ,t ,Rd = F v ,Rd k b ,θ

k b,θ

0,8



0,7 Carbon steel

0,6

F b ,t ,Rd = F b ,Rd k b ,θ

k y,θ

0,5



0,4 0,3

Bearing resistance of bolts in fire Tension resistance of a bolts in fire F ten ,t ,Rd = F t ,Rd k b ,θ

Weld k w,θ

0,2 0,1

γ Μ partial safety factor for the resistance

0 0

200

400

600

800

1000

θ a ,°C 71

γ Μ ,fi partial safety factor for fire

72

γ m γ m ,fi γ m γ m ,fi γ m γ m ,fi

Filled Weld Resistance at Elevated Temperature 

Design strength per unit length of a fillet weld in a fire F w ,t ,Rd = F w ,Rd k w ,θ

Butt Weld Resistance at Elevated Temperature 

For full penetration butt weld up to 700ºC as equal to the strength of the weaker part of the joint using the appropriate reduction factors for steel



For temperatures higher than 700ºC the reduction factors for fillet welds to butt welds

γ m γ m ,fi

γ Μ partial safety factor for the resistance γ Μ ,fi partial safety factor for fire

73


74

Component Method
















Component method






Summary



Decomposition of joint Componnet description Joint assembly

  



M

z



 



 

75

Component Method   

Component Method

Decomposition of joint Componet description Joint assembly

Component

 

Deformation F i ;θ

K i ;θ

=

k y ;θ k E ;θ

Stiffness K i ;θ = k E ,θ K i ; 20 º C ;

Decomposition of joint Componnet description Joint assembly

  

M i ;θ = k y ;θ M i ; 20 º C ;

Rotation

δ i ; 20 º C

φ i ;θ =

Stiffness

S i ;θ =

M i ;θ S i ;θ

=

k y ;θ k E ;θ



M

 

z



Moment

F i ;θ = k y ,θ F i ; 20 º C ; δ i ;θ =



Joint

Force

76



 

M, kNm

Moment

20 ºC

φ i ; 20 º C ;

100ºC 500ºC

50

600ºC

2

E θ z = k E ;θ S i ; 20 º C ; 1 ∑ k 77 i i ; θ

0

0

20

40

800ºC 60

700ºC 80

Rotation , mrad 100 78

P 28 500 kN

500 kN

150

Worked Example

Fire Resistance



Fire resistance of an end plate connection of the truss lower flange



Required R30

125

40

45

4 x M24



Unprotected Am / V = 54 ,0 / 1 ,24 = 43 ,18 m - 1 Section factor Fire resistance t = 44 min (exposed to nominal standard fire curve)



d p = 15 mm Protected Intumescent paint Am λ p 0 ,1 = 43 ,18 = 288 Wm - 3 K - 1 Fire resistance V d p 0 ,015 (exposed to nominal standard fire curve) t = 112 min 80

P 28 500 kN

85

500 kN

150

85

125

4 x M24

40 45

79


Structural Integrity












Component method






Summary



If used catenary actions of beams and slabs



In case of advanced design models



Resistance of connections to horizontal forces at ultimate limit state (for f u)

81

82

FE Simulation of Cardington Test

Experiment in Cardington

Normal force, kN 300 I. Beam only II. One section III. Full floor

200 100 0

40

20

60

-100

80

100 Time, min

-200 Model of structure

- 300 720°C Heating

Cooling 6 x 3,75 m

Observed joint I.

II. III.

4 x 6,0 m

83

84

Low Temperature Strain Gauges D1

PLAN

5th floor

Internal wall of the fire compartment 11,0 m 7,0 m

99

97

103

101

Window 1,27 x 8,70 m D1 UC 305 x 305 x 198

111

109

91

107, 111 89

85

87 E1 UC 305 x 305 x 137

83,87

95

115

20

113

119 15,2 127

309,2 (314,5) 320,5 y 13,8 (339,9) (19,1)

(31,4) 21,7

z

20

105, 109

89, 93

4th floor

500

117 115, 119

93 91, 95

81, 85 500

UC 305 x 305 x 137 (UC 305 x 305 x 198) 20

105

107

500

99, 103 97, 101 81

83

N

Protected Columns E1

113,117

At external columns

125

123

121 127, 123

121, 125 500

20

3rd floor

Internal

85

Measured Stresses at External Columns

External (with 1 m of beam)

86

Measured Bending Moments in Columns

Stress, MPa Column E1 91 89

Column D1 83 81

150

Bending moments, kNm 600

93 100

87

95 87

50

85

95

93

15

30

45

60

75

90

105

120

135

150

165

180

195

-100 -150

3rd floor

200

a-D1

2nd floor Time, min.

0 D1, E1

c-D1; c-E1 b-D1

c-E1

210

-50

81 83 89 91

d-D1; d-E1 4th floor

c-D1

400

Time, min.

0

5th floor

b-D1

0

60

D2

D1

120 d-E1

4th floor

500 mm

d-D1

-200 a-D1

-200

Section 500 mm above the floor at 4th floor 87

Measured Forces in External Columns Force, kN c-E1 3rd floor (5th foor)

100

60

-100 -200

4th floor

-300 -400 -500

d-D1 120

F t,5

F t,4 4th floor F t,4

d-E1

3rd floor

Time, min. d-D1 d-E1

c-D1; c-E1 b-D1



BS 5950: Structural use of steelwork in buildings



EN 1991-1-7 Actions – Exceptional loading

a-D1 Column ties

F t,3

F t,3 0

Required Tie Forces - References d-D1; d-E1

c-D1

200

0

F t,5 5th floor

Everage

300

88

2nd floor D2

D1 Tie anchoring re-entrant corner

Everage c-D1

c-E1 A

Beam model

Tie anchoring free column A Edge ties

Beams not used as ties

Forces at 3rd, 4th and 5th floor calculated from strainganges at level c,d 89

90

Required Tie Forces


Column ties

Tie anchoring re-entrant corner

A Tie anchoring free column A Edge ties

Beams not used as ties

F t = min [0,5 ( 1,4 g k + 1,6 qk ) st L; 75]












Component method






Summary

gk the characteristic value of permanent action, qk the characteristic value of variable action, L the beam span st

the mean transverse spacing of the ties adjacent to that being checked

91

Summary

List of Lessons at Seminar



Well designed connections at ambient temperature do not need to be recalculated at elevated temperature, if are not directly exposed to fire



The structural fire design according to EN 1993-1-2 is ready for design of connections exposed to fire

Thermal analyses of fire compartment or local fire EN 1991-1-2

92

Transfer of heat into structure

Mechanical behaviour at elevated temperature

1. 2. 3. 4. 5. 6. 7. 8. 9.


EN 199x-1-2 93

Thank you for your attention

95

94


Seismic Designof Connections Lessons Connection Design according to EN 1993-1-8 Prof. František Wald

Introduction Bases of design according to EN 1993-1-8 Welded connections Bolted connections Basicsof structural joints Design of simple connections Column bases Fire design of connections, EN 1993-1-2 Seismic design, EN 1998-1-1

1


Principles



Design criteria 

Beam-to-column typologies



Design and fabrication recommendations



Welding technology



Strain-rate loading



M - φ modelling



Column web panel



Summary

2

Principles 

Basic conditions   



Northridge and Kobe earthquake 



Over-strength demand Ductility demand (rotation capacity) Robustness demand (reliable detailing together with material behaviour)

Unexpected damages to connections

Detailing practices 

Welding

3


4

Design Criteria for Seismic Resistant Frames



Principles



Strong Column/Weak Beam design principle



Design criteria



Panel zone strength



Connection strength and degradation characteristics



P-δ effects



Member local buckling









Welding technology



Strain-rate loading



M - φ modelling



Column web panel



Summary

5

6

Requirements for Connection Successful Performance

Design Criteria in USA 

Guidelines designs for frames with different anticipated seismic demands 





1997 NEHRP Provisions

AISC Seismic Provisions 

Ordinary Moment Resisting Frames (OMRF) 



Intermediate Moment Resisting Frames (IMRF) 



Plastic rotation capacities of 0,01rad Plastic rotation capacities of 0,02rad



Special Moment Resisting Frames (SMRF) 

Plastic rotation capacities of 0,03rad

7

Design Criteria in Europe 





General rules for steel connections in dissipative structures

Rotational stiffness of a jointS j 



axial force NSd in the connected member not exceed 10%

Rotation capacity

Beam-to-ColumnTypologies



Base Material Notch-Toughness



Weld Wire Notch-Toughness



Weld backing and Run out Tabs



Reinforcing Fillet Welds



Cope Hole Size, Shape, Workmanship

Bolted Joints 

Bolt Sizing, Hole Type, Tightening



Net Section Strength

8



Design criteria 







Welding technology



Strain-rate loading



M - φ modelling



Column webpanel



Summary

10

Connection Types

FEMA/SAC test programmes 



Principles

9



Through-Thickness Strength



Requirements for MRF (Moment Resistant Frame) beam-to-column connections

EN 1993-1-8 




EN 1998-1-1 basic provisions concerning steel joints 

Welded Joints



Prescriptive Moment Frame Connection

Connection type classified for certain ranges of 

Member size



Plastic rotation angle

Connection types 

Welded Unreinforced Flange (WURF)



Welded Cover Plated Flange (WCPF)



Welded Flange Plates (WFP)



Welded Vertical Ribbed Flange (WVRF)



Welded Column Tree with Bolted Beam (WCT/BB)



Welded Single Haunch (WSH)



Welded Double Haunch (WDH)

11

12

Welded Flange Plate Connection

Welded Column Tree with Bolted Beam

13

Field Bolted Types of Connections 

Field Bolted Types of Connections

Guidelines as pre-qualified for certain conditions of use 

Bolted end plate (BEP)



Welded flange plates with bolted beam(WFPBB)



Bolted single haunch(BSH)



Bolted double haunch(BDH)

14



Bolted end plate (BEP)

15

Field Bolted Types of Connections 

16

Field Bolted Types of Connections

Welded flange plates with bolted beam(WFPBB)

17



Bolted double haunch (BDH)

18

Beam-to-ColumnTypologies 


Specific joints in Japan



Specific joints in Europe 

Stiffener

Extended endplate joint

A

Stiffener

A

. . . 10M20 - 10.9 A-A

19

Beam-to-ColumnTypologies 



Welded joint

20



B

B


Welded flange plate joint

C

C

.

. .

.

.

.

3M20 - 6.6 C-C

B-B

21

General Rules for Steel Connections in Dissipative Structures


Principles



Design criteria 







Welding technology



Strain-rate loading



M - φ modelling



Column web panel



Summary

22



Localisation of plastic strains, high residual stresses, and fabrication defects 



Non dissipative connections of dissipative members 

Full penetration butt welds 



By experimental evidence

Deemed to satisfy the overstrengthcriterion

For fillet weld or bolted non dissipative connections Rd ≥ 1 ,35 R fy

23

24

General Rules for Steel Connections in Dissipative Structures 

Bolted joints  

Shear joints with fitted bolts are also allowed.



Theshear resistance of the bolts should be higher than 1,2 times the bearing resistance

 



 



26

Design and Fabrication Recommendations 

Plastic rotation capacity φ Cd in the plastic hinge Not less than 35mradfor structures of ductility class H and 25mrad for structures of ductility class M withq>2. Under cyclic loading without degradation of strength and stiffness greater than 20% Supported by experimental evidence

Partial strength connections 

Connections have a rotation capacity consistent with global deformations Members framing into the connections are demonstrated to be stable at the ultimate limit state (ULS) Effect of connections deformation on global drift is taken into account

25

Connection design 





Requirements for Moment Resistant Frame Beam-to-ColumnConnections 

Connections between the beams and the columns should be designed for the required degree of overstrength Moment resistanceMpl.Rd and the shear force (VG, E d + V M,Ed) evaluated in 6.6.2 of standard EN 1998-1

Dissipative semi-rigid and/or partial strength connections are permitted provided all of the following conditions

Should be supported by experimental evidence For all types of connections in dissipative zones Available plastic rotation φ = δ /( 0 ,5 L ) p





The strength and ductility of members and their connections under cyclic loading 



Structure dissipate energy in the beams 

Boltedshear connection 





In shear categories B and C (slip resistant) only Un tension category E With controlled tightening of the bolts 



Requirements for Moment Resistant Frame beam-to-column connections



Material properties Yield-to-Ultimate Stress Ratio (YUSR) 

YUSR (f y/f u) = 0,65 or 0,80 



YUSR = 0,95 



Column capacity design from the plastic capacity of connections

For a plastic rotation capacity up to 0,030 rad. Reduced plastic hinge length at a plastic rotation capacity of 0,030 rad

The plastified length of the beam with YUSR= 0,95 

Half the corresponding length in YUSR = 0,80

27


Principles



Design criteria 







Welding technology



Strain-rate loading



M - φ modelling



Column web panel



Summary

28

Design and Fabrication Recommendations 

29

Access Hole Size and Geometry

30

Design and Fabrication Recommendations  


Access Hole Size and Geometry Increasing the size of the web cope  

Easier welding on the beambottom flange Better weld quality



Principles



Design criteria

25 25

10 10

20

38

25

20

25

50

Standard Modified Configurations of weld access hole





  






Welding technology

Strain-rate loading



M - φ modelling



Column webpanel



Summary

32

Strain-Rate of Carbon Steel

The strain-rate loading has an important influence on the behaviour of joints A strain rate typical for steel members yielding under seismic action in the range of 0,03-0,06 s-1 




31

Strain-Rate Loading



Stress

Increasesthe yield strength Lower ultimate strength of welded connections Ductility is reduced by up to 27% Decrease of ductility due to high strain rates is not straightforward for cyclic loading

Conventional speed E

Very high speed

Strain

33

Strain-Rate of Carbon Steel

34

Strain-Rate of Austenitic Steel

α DIF , fy = f y ,dyn / f y

800

α DIF , fu = f u .dyn / f u

600

Stress, MPa

α DIF . fy

>1s 100 ms 10 ms 1 ms

1,0 1,1 1,6 1,9

α DIF . fu

-1 -2 -1

10 s

-4 -1

10 s

140 s -1

400

Time to yield stress

502 s

50 s -1 200

1,00 1,05 1,05 1,05

Strain, %

0 15 

35

30

45

60

EN 10088-2 1.4307 (304L) increaseof f 02 o cca 7% - 28%

75

36


M - φ Modelling



Principles



Stable behaviour



Design criteria



Unstable curve



Slip in connection









Welding technology



Strain-rate loading



M - φ modelling



Column web panel



Summary

Stable behaviour



Unstable curve



M

φ

φ

φ

37

38

Parametres

M - φ Modelling 

M

M

Slip in connection



Rotational capacity



Energy







39

β Δ .i =

β e =

Rotational capacity and energy

E i

β E .i =

β M .i =

Resistance

E i φ i

φ el M j .el (φ ix − φ el ) S j .i S j .ini M j .i M j .ini

M

Models 

Exponential Curve

Curve fitting



Initial stiffness

S j,ini



Initial stiffness



Moment resistance

M0



Moment resistance



Unloading

S j,s





M a



Assembling

S j.ini

S j.s S j.ini

φ a

φ

S j.s - M 0

Component Component cycling description

40

M 0

Unloading



φ j .el

M j .el (φ i − φ el )

β S .i =

Stiffness

φ j .i

M j = S j .i φ i = M i −1 −

41

) − S j .s (φ a − φ ) 1 / n n ⎤ (S j .ini − S j .s )(φ a − φ ) S j .ini − S j .s (φ a − φ )

⎡ ⎢1 + ⎢⎣

2 M 0

⎥ ⎥⎦

42

PP Connection Design According to en 1993-1-8

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