connection design according to en 1993 part 1-8 -
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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 KORKEAKOULUTEKNISKA HÖGSKOLANHELSINKI UNIVERSITY OF TECHNOLOGYTECHNISCHE UNIVERSITÄT HELSINKIUNIVERSITE DE TECHNOLOGIE D’HELSINKI
1
Introduction
Lessons Connection Design according to EN 1993-1-8
Prof. František WaldCzech Technical University in Prague
2
List of Lessons at Seminar1. Introduction2. Bases of design according to EN 1993-1-83. Welded connections4. Bolted connections5. Basics of structural joints6. Design of simple connections 7. Column bases8. Fire design of connections, EN 1993-1-29. Seismic design, EN 1998-1-1
3
SummaryList of contentTiming National Annexes CeStruCoAccess STEELSummary
CeStruCo
in Window Help Formatwith PP Presentations
Lessons
4
List of Content in EN 1993-1-81. Introduction2. Basis of design3. Connections made with bolts, rivets or pins4. Welded connections5. Analysis, classification and modelling6. Structural joints connecting H or I sections7. Hollow section joints
5
SummaryList of contentTiming National Annexes CeStruCoAccess STEELSummary
CeStruCo
in Window Help Formatwith PP Presentations
Lessons
6
Development of EurocodesECCS Concept in 1978ECCS First draft in 1984CEN Started with Eurocodes in 1990CEN ENV 199x-x-x in 1992 (actions nationally only)CEN EN 199x-x-x in 2005
AdvantagesEuropean agreementAll structural materials under one safety concept
WeaknessCopyrightsSize (some countries only rules, some textbooks)
7
List of EurocodesEN 1990 Eurocode 0: Basis of Structural Design EN 1991 Eurocode 1: Actions on structuresEN 1992 Eurocode 2: Design of concrete structuresEN 1993 Eurocode 3: Design of steel structures
Project team Prof. F. Bijlaard
EN 1994 Eurocode 4: Design of composite steel and concrete struc.Project team Prof. D. Anderson
EN 1995 Eurocode 5: Design of timber structuresEN 1996 Eurocode 6: Design of masonry structuresEN 1997 Eurocode 7: Geotechnical designEN 1998 Eurocode 8: Design of structures for earthquake resistanceEN 1999 Eurocode 9: Design of aluminium structures
8
Eurocodes List of ActionsEN 1991-1-1 Actions – Dead load published 04/02EN 1991-1-2 Actions – Fire 11/02EN 1991-1-3 Actions – Snow 07/03EN 1991-1-4 Actions – Wind 04/05EN 1991-1-5 Actions – Temperature 11/03EN 1991-1-6 Actions – During erection 06/05EN 1991-1-7 Actions – Exceptional 05/06EN 1991-2 Actions – Transport on bridges 09/03EN 1991-3 Actions – Crane girders 11/06EN 1991-4 Actions – Silos and tanks 08/05
9
Structural Steel Eurocodes (20 documents)EN 1993-1-1 Basic rules First package 05/05EN 1993-1-2 Fire resistance 04/05EN 1993-1-3 Thin walledEN 1993-1-4 Corrosion resistantEN 1993-1-5 PlatesEN 1993-1-6 ShellsEN 1993-1-7 Plates 2EN 1993-1-8 Connections 05/05EN 1993-1-9 Fatigue 05/05EN 1993-1-10 Brittle fracture 05/05EN 1993-1-11 Tensile members (cables)EN 1993-1-12 HSSEN 1993-2 BridgesEN 1993-3-1 MastEN 1993-3-2 ChimneysEN 1993-4-1 SilosEN 1993-4-2 TanksEN 1993-4-3 PipelinesEN 1993-5 PilotsEN 1993- 6 Crane girders
10
Development of EN 1993-1-8From ENV 1991-1 Chapter 6 Connections
Annex J JointsAnnex L Base platesAnnex K Hollow section joints
ECCS TC10 comments to ENV 1993-1-1 May 12, 1992CEN/TS250/SC3 project team, head Mr. Jouko Kouhi VTT, FinlandprEN 1993-1-8 document N 1054 E Sept. 9, 2001900 national commentsFinal draft Nov. 20, 2001Voting April 16, 2004Acceptation by CEN May 11, 2005
11
Eurocode Implementation - ExamplesTranslationsUK N/A; France 12/2006; Poland 2007; Czech Rep. 8/2006
National AnnexesUK 12/2007; France 12/2006; Poland 2010; Czech Rep. 8/2006
Eurocodes be adopted for government constructionUK unknown; France Not; Poland 2010; Czech Rep. 2008
Eurocodes be adopted for non-government constructionUK unknown; France Not; Poland 2010; Czech Rep. 2008
National standards withdrawnUK 2010; France 2010; Poland 2010; Czech Rep. 2010
12
SummaryList of contentTiming National Annexes CeStruCoAccess STEELConclusions
CeStruCo
in Window Help Formatwith PP Presentations
Lessons
13
National Annex for EN 1993-1-8Alternative proceduresNationally Determined Parameters
National choice is allowed in EN 1993-1-8 through (only):1.2.6(6) Reference standard Rivets2.2(2) Partial safety factors3.1.1(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
14
National Choice (Czech Rep.)Clause 1.2.6 Reference Standards, Group 6: Rivets
ČSN 02 2300: Rivets, Overview (Czech national standards).Clause 2.2 Partial safety factors, paragraph (2)
Numerical values of partial safety factors for joints are not changed, the valuesin Table 2.1 should be used.
Clause 3.1.1(3) General, paragraph (2)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.
Clause 5.2.1 General, paragraph (2)No additional information on classification of joints by their stiffness and strength are given to that included in 5.2.1(2).
Clause 6.2.7.2 Beam-to-column joints with bolted end-plate connections, paragraph (9)
The requirements for elastic distribution of forces in the bolt rows introducedin (6.26) are not changed.
15
SummaryList of contentTiming National Annexes CeStruCoAccess STEELSummary
CeStruCo
in Window Help Formatwith PP Presentations
Lessons
16
CeStruCo =Civil enginnering Structural Connections
Aristotle University of Thessaloniki, GreeceBouwen met Staall, NetherlandsBuilding Research Establishment Ltd., United KingdomCzech Technical University (contractor), Czech RepublicLuleå University of Technology, SwedenUniversity of Coimbra, PortugalPolitechnica University of Timisoara, Romania
ReviewKREKON Design office, Rotterdam, Netherlands Czech EXCON a.s., Prague, Czech RepublicConstructional Steelwork Association Ostrava, CR
17
European Educational ProjectsESDEP Basic European educational projectWIVISS CD lessonsSteelCall Virtual officeStainless SteelCall Internet/CDSSEDTA PP presentation + lessonsCeStruCo Connection designNFATEC Internet coursesSDCWASS Austenitic stainless steelDIFISEK Fire design
18
Textbook1. Introduction 2. Bolts 3. Welding 4. Structural Modelling 5. Simple Connections 6. Moment Resistance Connections7. Column Bases8. Seismic Design9. Fire Design10. Hollow Section Joints11. Cold-Formed Member Joints12. Aluminium Connections13. Design Cases
19
Internet / CD VersionLessons in Window help formatTextbook in PDF fileWorked examplesPresentations
PowerPointProgramme „Nonlinear analyses of joints by component method“Video film
Tools for connection designExample of SoftwareExample of Tables
20
Lessons in Window Help Format
Prepared by RoboHelp tool at Czech Technical University in Prague
21
PowerPoint Presentations
Based on Fire test on 8th storey building Cardington, January 16, 2003 22
Software
Non-linear Analysis of Steel ConnectionsCoimbra UniversityPrediction of behaviour by component method with nonlinear force - deformation diagram of components
23
Video Film
Statically Stressed Bolts in Dynamically Loaded Connectionsprepared at Delft University
24
CeStruCo on CD
Educational material to support conversion of ENV 1993-1-1 to EN1993-1-8
CD / Internet lessons
www.fsv.cvut.cz/cestrucoCeStruCo
in Window Help Formatwith PP Presentations
Lessons
25
SummaryList of contentTiming National Annexes CeStruCoAccess STEELSummary
CeStruCo
in Window Help Formatwith PP Presentations
Lessons
26
Access STEEL – Informational tool at www.access-steel.com
27
Access STEEL – Information SystemEurocodes 1993-1-x and EN 1994-1-x for not steel specialists
Project Initiation Scheme Development Detailed Design Verification
For practising designers, architects and their clientsDetailed design of elementsStep-by-step guidanceFull supporting information Worked examplesInteractive worked examples
English, French, German and SpanishProject of EU eContent Programme
28
Access STEEL - DocumentsTopics
Multi-storey Buildings Single Buildings Residential Construction
Fire Safety Engineering
250 separate technical resources + 50 interlinked modules Client's guideConcept designsFlow Charts
Non-conflicting Complementary InformationWorked examples (Pasive and Interactive)
29
Example - Client's Guide
30
Example - Concept Designs
31
Example - Flow Charts
32
Example - Non-Conflicting Complementary Information
33
Example – Pasive Worked Example
34
Example – Interactive Worked Example
35
Access STEELInformational system based on hypertext engine
36
SummaryEN 1993-1-8 – Connectors and jointsEN 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
1
Bases of Designaccording to EN 1993-1-8
Lessons Connection Design according to EN 1993-1-8
Prof. František Wald
2
List of Lessons at Seminar1. Introduction2. Bases of design according to EN 1993-1-83. Welded connections4. Bolted connections5. Basics of structural joints6. Design of simple connections 7. Column bases8. Fire design of connections, EN 1993-1-29. Seismic design, EN 1998-1-1
3
TopicsBases of DesignEccentricity at IntersectionsConnection Modelling in Global AnalysesGlobal Analysis of Lattice GirdersClassification of JointsModelling of Beam-to-Column Joints Summary
4
General RequirementsAll 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.
5
Effect of actionsResistance
Frequency bar chart
Partial safety factors for jointsResistance of members and cross-sections γM0, γM1, γM2
Resistance of bolts, rivets, pins, welds, plates in bearing γ M2
Slip resistance γ M3, γ M3,ser
Bearing resistance of an injection bolt γ M4
Resistance of joints in hollow section lattice girder γ M5
Resistance of pins at serviceability limit state γ M6,ser
Preload of high strength bolts γ M7
Recommended valuesγ M2 = γ M3 = 1,25 (EN 1993-1-1 γ M0 = 1,00, γ M1 = 1,10) γ M3,ser = γ M7 = 1,10γ M4 = γ M5 = γ M6,ser = 1,00
6
Applied Forces and MomentsThe forces and moments applied to joints at the ultimate limit state should be determined according to the principles in EN 1993-1-1.
7
Resistance of JointsOn the basis of the resistances of its basic components
Linear-elastic or elastic-plastic analysis
Fasteners with different stiffnessesWith the highest stiffness should be designed to carry the load. (An exception bolts and slip resistant bolts).
8
TopicsBases of DesignEccentricity at IntersectionsConnection Modelling in Global AnalysesGlobal Analysis of Lattice GirdersClassification of JointsModelling of Beam-to-Column Joints Summary
9
Eccentricity at IntersectionsThe joints and members should be designed for the resulting moments and forces
Except in the case of particular types of structures - lattice girdersIn the case of joints of angles or tees attached by either a single line of bolts or two lines of bolts
Centroidal axes
Setting out lines
Fasteners
Fasteners
10
Reduction of Resistance of Angles Connected by One Leg(and other unsymmetrically connected members in tension)
Reduction factors Pitch p1 < 2,5 do > 5,0 do 2 bolts β2 0,4 0,7 3 bolts or more β3 0,5 0,7
With 1 bolt: Nu,Rd = 2
02 )5,0(0,2
M
uftdeγ−
With 2 bolts: Nu,Rd = 2
2
M
unet fAγ
β
With 3 or more bolts: Nu,Rd = 2
3
M
unet fAγ
β
11
TopicsBases of DesignEccentricity at IntersectionsConnection Modelling in Global AnalysesGlobal Analysis of Lattice GirdersClassification of JointsModelling of Beam-to-Column Joints Summary
12
Types of Joint Modelling
Simple--Pinned
-Semi-continuousSemi-continuousSemi - rigid
-Semi-continuousContinuousRigid
PinnedPartial-strengthFull-strength
RESISTANCESTIFFNESS
13
Elastic analysis at the Serviceability Limit StateDesign joint properties based on the type of global analysis
Initial stiffness Sj,ini and resistance Mj.Rd
M
Mj,Rd
j,Sd
23
Sj,ini
M
φ
14
Elastic analysis at the Ultimate Limit StateModified stiffness Sj,ini and resistance Mj,Rd
η is stiffness modification coefficient
M
Mj,Rd
j,Sd S / j,ini
M
φ
η
S j,ini
15
Stiffness Modification Coefficient η
3-Base plates3,52Bolted flange cleats32Bolted end-plates32Welded
Other types of joints (beam-to-beam joints, beam splices, column
base joints)
Beam-to-column jointsType of connection
M
Mj,Rd
j,Sd S / j,ini
M
φ
η
S j,ini
16
Rigid - Plastic AnalysisResistance Mj,Rd and deformation capacity φCd
M j,Rd
M
φφCd
17
Elastic - Plastic AnalysisFull curve description
M j,Rd
M
φφCd
S j,ini
18
Joint Modelling and Frame Global Analysis
PinnedPinnedPinnedSimple
Rigid/partial-strengthSemi-rigid/full-strength
Semi-rigid/partial-strength
Partial-strengthSemi-rigidSemi-continuous
Rigid/full strengthFull-strengthRigidContinuous
Elastic-plastic analysisRigid-plastic analysis
Elastic analysis
TYPE OF FRAME ANALYSISMODELLING
19
TopicsBases of DesignEccentricity at IntersectionsConnection Modelling in Global AnalysesGlobal Analysis of Lattice GirdersClassification of JointsModelling of Beam-to-Column Joints Summary
20
Global Analysis of Lattice GirdersHollow sectionsAssumption the members connected by pinned joints (for the distribution of axial forces)
Secondary moments (due to rigidity of joints)Moments resulting from transverse loadsMoments resulting from eccentricities
Not (if criter. is satisfied)JointNoBrace memberNoTension chordYes
YesNot if criter. is satisfied
Compression chordEccentricityTransverse loadingSecondary effects
Source of the bending momentType of component
21
Secondary MomentsMoments, caused by the rotational stiffness's of the joints, may be neglected in the design of members and joints.
Joint geometry is within the rangeRatio of the system length to the depth of the member in the plane is not less than 6
22
Moments Resulting from Transverse LoadsMomets should be taken into account in the design of the members to which they are applied
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.
Chords may be considered as continuous beams, with simple supports at panel points.
23
Moments resulting from Eccentricities
Centric
Negative eccentricity
Positive eccentricity
24
Moments resulting from EccentricitiesMay be neglected in the design of tension chord members and brace membersMay be neglected in the design of connections if the eccentricities are within the limits:
−0,55 d0 ≤ e ≤ 0,25 d0
−0,55 h0 ≤ e ≤ 0,25 h0
e eccentricityd0 diameter of the chordh0 depth of the chord, in the plane of the lattice girder
25
TopicsBases of DesignEccentricity at IntersectionsConnection Modelling in Global AnalysesGlobal Analysis of Lattice GirdersClassification of JointsModelling of Beam-to-Column Joints Summary
26
Based on Resitance
φ
Full strength connection
Partial strength connection Bending moment resistance
MMoment,
Rotation,
of connected beam
M b,pl,Rd
27
Based on Stiffness (Values for Column Bases)Accuracy of calculation
5% Ultimate Limit State20% Serviceability Limit State
0
0,2
0,4
0,6
0,8
0 0,01 0,002 0,003
1,0
Sj.ini.c.s
S j.ini.c.n = 30 E I / L cc
c c = 12 E I / L
Relative moment
36,1o =λ
M j / M pl,Rd
, radPinned column base
Semi-rigid column base
Rigidcolumn base
φ_
= EL M
c
c c,pl,Rd
I φ
φ28
Based on Rotational CapacityDeformation capacity of connected member
M
φ
Elastic rotation
(Class 2)(Class 1)
(Class 3)Brittle connection
Ductile connectionSemi-ductile connection
φ
M M
φM
Moment,
Rotation,
of connected beam
Ultimate rotationof connected beam
29
Column Bases – Braced FramesPrediction of column resistance based on the lower support bending stiffness
01020304050
0 2 4 6 8 10Relative slenderness of column
Simplified boundary
Accurate boundary
S j.iniE I / Lc c
Relative stiffness of base plate
0λ30
Column Bases – Braced FramesPrediction of column resistance based on the lower support bending stiffness
for 5,0≤λ is the limit 0S ini.j > ,
for 93,35,0 << λ is the limit ccini.j L/IE)12(7S −≥ λ ,
and for λ≤93,3 is the limit ccini.j L/I48S ≥ .
The limiting stiffness 12 E Ic / Lc (slenderness lower than 36,1=λ )
31
Classification of JointsNational Annex may give additional information on the classification of joints by their stiffness and strengthin Cl 5.2.2.1(2)Pin is difficult to define
Small moment resistanceSmall stiffnessHigh deformation/rotational capacity
32
TopicsBases of DesignEccentricity at IntersectionsConnection Modelling in Global AnalysesGlobal Analysis of Lattice GirdersClassification of JointsModelling of Beam-to-Column Joints Summary
33
Modelling of Joint by Rotational SpringsComponent method
Joint Shear panel Shear panel separatelly in connections
φT
MaM b
b
φa
Ma M b
34
Shear Panel
Forces and moments acting on the joint
Forces and moments acting on the web panel at the connections
Mb2,Ed
Nb2,Ed Vb2,Ed Vb1,Ed
Mb1,Ed
Nb1,Ed
35
Distribution of Internal Forces
Shear forcesA bolt row in shear onlyRest of shear resistance of each bolt rowSupplement of shear resistance of each bolt row
Plastic distribution
Ft1.Rd
Fc.Rd
Ft2.Rd
F t3.Rd
≤
=
=
=
Elastic-plastic distribution
F t1.Rd
F c.Rd
F t2.Rd
< F t3.Rd
≤
=
=
Elastic distribution
Ft1.Rd
F c.Rd
< F t2.Rd
< F t3.Rd
=
z3
z2
z1
≤
36
TopicsBases of DesignEccentricity at IntersectionsConnection Modelling in Global AnalysesGlobal Analysis of Lattice GirdersClassification of JointsModelling of Beam-to-Column Joints Summary
1
Welded Connections
Lessons Connection Design according to EN 1993-1-8
Prof. František Wald
2
List of Lessons at Seminar1. Introduction2. Bases of design according to EN 1993-1-83. Welded connections4. Bolted connections5. Basics of structural joints6. Design of simple connections 7. Column bases8. Fire design of connections, EN 1993-1-29. Seismic design, EN 1998-1-1
3
TopicsBases of designFillet weld
Design modelDesign independent of the direction of loadingVery long welds Design exampleEffective width of welded beam-to-column connectionWeld design for full resistance of connecting members
Welding in cold-formed zonesDesign of partially penetrated butt weldSummary 4
Bases of Design
Fillet weldsBut weldPlug weldsGroove welds
EN 1993-1-8 requirementsDesign rules + Design models
a
5
Fillet welds –Definition of Effective Throat Thickness a
The effective throat thickness of a fillet weld should not be less than 3 mm
Design throat thickness of flare groove welds in rectangular structural hollow section 6
TopicsBases of designFillet weld
Design modelDesign of independent of the direction of loadingVery long welds Example - Modelling the resistanceEffective width of welded beam-to-column connectionWeld design for full resistance of connecting members
Welding in cold-formed zonesDesign of Partially Penetrated Butt WeldSummary
7
Design Model of Fillet Welds
a effective throat thickness of the fillet weldσ┴ normal stresses perpendicular to the throatσ║ normal stresses parallel to the axis of weld (omitted)τ┴ shear stresses perpendicular to the axis of weldτ║ shear stresses parallel to the axis of weld 8
Plane StressesHuber –Misses- Henckey condition of plasticity (HMH)
Triaxial state of stress (needed exceptionally only)Plane state of stress (needed very often)
σx2 + σz
2 - σx2 σz
2 + 3τ2 ≤ (fy / γM) 2
Uniaxial state of stress (from the material tests)σ ≤ fy / γM0
τ ≤ fy / (γM0 √3)
σx
σz
9
Design Model
( )2II
22 3 τ+τ+σ ⊥⊥ ( )Mwwuf γβ≤
⊥σ Mwuf γ≤
fu Ultimate tensile strength of connected materialβw Correlation factor
γMwpartial safety factor for material of welds10
Correlation factor βw for fillet welds
1,00S 460 NH/NLHS 460 MH/MLHS 460 NH/NLH
S 460 N/NLS 460 M/ML
S 460 Q/QL/QL1
1,00S 420 MH/MLHS 420 N/NLS 420 M/ML
0,90S 355 H
S 355 NH/NLHS 355 MH/MLH
S 355 HS 355 NH/NLH
S 355S 355 N/NLS 355 M/ML
S 355 W
0,85S 275 H
S 275 NH/NLHS 275 MH/MLH
S 275 HS 275 NH/NLH
S 275S 275 N/NLS 275 M/ML
0,80S 235 HS 235 HS 235S 235 W
EN 10219EN 10210EN 10025Correlation factor
βw
Standard and steel grade
11
TopicsBases of designFillet weld
Design modelDesign independent of the direction of loadingVery long welds Example - Modelling the resistanceEffective width of welded beam-to-column connectionWeld design for full resistance of connecting members
Welding in cold-formed zonesDesign of Partially Penetrated Butt WeldSummary 12
Design Independent of the Direction of Loading
Mww
ud,vw
ffγβ3
=
d,vwRd,w faF =
F w,Rd
V// ,Sd
F w,Sd
L a
N Sd
V⊥,Sd
F w,Rd
⊥
13
TopicsBases of designFillet weld
Design modelDesign of independent of the direction of loadingVery long welds Design exampleEffective width of welded beam-to-column connectionWeld design for full resistance of connecting members
Welding in cold-formed zonesDesign of Partially Penetrated Butt WeldSummary 14
Very Long WeldsOverloading of weld ends
due to the different deformation of the connected elements
τ ττ τ
Lw
//// // //
15
Long welds
Reduction of design strength( ) 011502021 ,aL,, wLw ≤−=β
00 50 100 150 200 250 300 350 400
βLw
L / a0,20,40,60,81
τ τ
Lw
////
16
TopicsBases of designFillet weld
Design modelDesign of independent of the direction of loadingVery long welds Design examplesEffective width of welded beam-to-column connectionWeld design for full resistance of connecting members
Welding in cold-formed zonesDesign of Partially Penetrated Butt WeldSummary
17
Two Fillet Welds in Parallel Shear τ la2F=
From plane stress analysis is
( )3fa2F Mwwu γβ≤l
18
0=τΙΙ
2Rσ=τ=σ ⊥⊥
Has to be satisfied
( )Mwwu22 f3 γβ≤τ+σ ⊥⊥
After substitution
( ) ( ) ( )Mwwu2R
2R
2R f2232 γβ≤σ=σ+σ
( )2f MwwuR γβ≤σ
Fillet Weld in Normal Shear
19
Connection of CantileverShear force Sd = FSd.
ha2FSdII =τ
Bending moment Sd = FSd e Transferred by the shape of weld.
Centre of gravity, Iwe and cross section modulus we
For weld at lower flange cross section modulus we,1 and stress is
( ) 1,weSd11 W2M=τ=σ ⊥⊥
For upper weld on flange is
( ) 2,weSd22 W2M=τ=σ ⊥⊥
V
M
WW
Transferred by web
fillets
20
Flange - WebWeld VSd
Vl
Welds are loaded by longitudinal shear force
ISVV Sd=l
where VSd
S Static moment of flange to neutral axisI moment of inertia
This longitudinal force is carried by two welds effective thickness aShear stress
3fa2V MwwuII γβ≤=τ l
Maximum stress is at the point of maximum shear force
shear force
21
TopicsBases of designFillet weld
Design modelDesign of independent of the direction of loadingVery long welds Worked ExamplesEffective width of welded beam-to-column connectionWeld design for full resistance of connecting members
Welding in cold-formed zonesDesign of Partially Penetrated Butt WeldSummary 22
Effective Width of Welded Beam-to-Column ConnectionConnection to plate deformed out of its plate
23
Effective WidthUnstiffened column flangesIn EN 1993-1-8 Chapter 4.10
twc thickness of column webtfc thickness of column flangetfb thickness of beam flange s equal to fillet radius rc for hot rolled column sections
fcwceff tstb 72 ++=
⎟⎟⎠
⎞⎜⎜⎝
⎛⎟⎟⎠
⎞⎜⎜⎝
⎛++=
yb
yc
fb
fcwceff f
fttstb
2
72
beff
t fb
t fctwc
rc
σ
24
Effective WidthUnstiffened column flangesIn EN1993-1-8 Clause 6.2.4.4
twc is thickness of column webtfc thickness of column flangetfb thickness of beam flange s is equal to fillet radius rc for hot rolled column sections
( )0
72M
ybfbfcwcRd,fc,t
fttkstF
γ++=
⎟⎟⎠
⎞⎜⎜⎝
⎛= 1min ;
tftf
kfbyb
fcyc
25
TopicsBases of designFillet weld
Design modelDesign of independent of the direction of loadingVery long welds Example - Modelling the resistanceEffective width of welded beam-to-column connectionWeld design for full resistance of connecting members
Throat thickness of a fillet weld used in a hollow section jointsDesign of Partially Penetrated Butt WeldSummary 26
Weld Design for Full Resistance of Connecting Members - Loading by Normal Force
Not directly in code
σ = FSd / (t h)FSd the acting design forcefu plate design strengtht the thinness of connecting plateb width of connecting platefull capacity of a plate the thickness S235:
Mwu /ft,a
γσ70>
t,t,,/
t),/(,/f
t)/f(,a
Mwu
My 50520251360
1012357070 0 ≈==>γγ
σ τ⊥
w
σ ⊥
σ F
tSd
27
τ
τ
h
t
VSd
Weld Design for Full Resistanceof Connecting Members - Loading by Shear Force
τ = VSd / (t h) VSd the design shear force in weld
full capacity of a plate the thickness S235
t,t,,/
t),/(,/f
t)/(f,
/ft,a
Mwu
My
Mww40360
251360311235850
3850850 0 ≅=
∗=≈>
γγ
γτ
28
Weld Designor Full Resistance of Connecting Members
Loading by shear force ∼ 0,5 t
Loading by normal force ∼ 0,4 t
29
TopicsBases of designFillet weld
Design modelDesign of independent of the direction of loadingVery long welds Example - Modelling the resistanceEffective width of welded beam-to-column connectionWeld design for full resistance of connecting members
Welding in cold-formed zonesDesign of partially penetrated butt weldSummary 30
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 weldingr / t - ratio satisfy the relevant values:
anyany2412106
≥ 25≥ 10≥ 3,0≥ 2,0≥ 1,5≥ 1,0
Maximum thickness (mm)Fully killed Aluminium-killed steel
(Al ≥ 0,02 %)r / t
31
TopicsBases of designFillet weld
Design modelDesign of independent of the direction of loadingVery long welds Example - Modelling the resistanceEffective width of welded beam-to-column connectionWeld design for full resistance of connecting members
Welding in cold-formed zonesDesign of partially penetrated butt weldSummary 32
Butt weldsFully suply the cross-section
For low quality is decreased design strengthCalculation as fillet weld
V
1/2 V
U
π
33
Design of Partially Penetrated Butt Welda = anom – 2 mm
a
cnom
t
anom.2
a nom.1a
a
nom
nom nom
34
Full penetration T joints
Partial penetration with an effective width
.
taa ,nom,nom ≥+ 21
5tcnom ≤
mm3≤nomc
taa ,nom,nom <+ 21
mm2nom,11 −= aamm2nom,22 −= aa
a
cnom
t
anom.2
a nom.1a
a
nom
nom nom
35
TopicsBases of designFillet weld
Design modelDesign of independent of the direction of loadingVery long welds Example - Modelling the resistanceEffective width of welded beam-to-column connectionWeld design for full resistance of connecting members
Welding in cold-formed zonesDesign of partially penetrated butt weldSummary 36
SummaryChapter 4 Welded connections
+Rules for connection of open sections
Component methodRules for connection of hollow sections
Welded
1
Bolted Connections(Connections made with bolts, rivets or pins)
Lessons Connection Design according to EN 1993-1-8
Prof. František Wald
2
List of Lessons at Seminar1. Introduction2. Bases of design according to EN 1993-1-83. Welded connections4. Bolted connections5. Basics of structural joints6. Design of simple connections 7. Column bases8. Fire design of connections, EN 1993-1-29. Seismic design, EN 1998-1-1
3
Scope of the LectureGeneral Design resistance of individual fasteners
Non-preloading bolts Single lap jointsBearing through packingSlotted holesLong joints RivetsAnchor bolts
Slip-resistant connections using 8.8 or 10.9 bolts Design for block tearing Lug angles Pin connectionsInjection bolts Summary 4
Material
Nominal values of the yield strength fyband the ultimate tensile strength fub for bolts
Note: Bolts 12.9 are not allowed
1000800600500500400400fub (N/mm2)
900640480400300320240fyb (N/mm2)
10.98.86.85.85.64.84.6Bolt class
5
Categories of Bolted Connections
8.8 or 10.9Ft,Ed ≤ Ft,RdFt,Ed ≤ Bp,Rd
EPreloaded
from 4.6 to 10.9Ft,Ed ≤ Ft,RdFt,Ed ≤ Bp,Rd
DNon-preloaded
Tension connections
8.8 or 10.9Fv,Ed ≤ Fs,RdFv,Ed ≤ Fb,Rd
Fv,Ed ≤ Nnet,Rd
CSlip-resistant at ultimate
8.8 or 10.9Fv,Ed.ser≤ Fs,Rd,serFv,Ed ≤ Fv,RdFv,Ed ≤ Fb,Rd
BSlip-resistant at serviceability
from 4.6 to 10.9Fv,Ed ≤ Fv,RdFv,Ed ≤ Fb,Rd
ABearing type
Shear connections
6
Holes (ENV 1990)Normal
+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) Accurate – flushed bolts
for bolt M20 must be the clearance Δd < 0,3 mm
7
p 1
p2
e 1
e 2
Positioning of Holes for Bolts and Rivets
Minimum values for spacings
2,4 d0Spacing p2
2,2 d0Spacing p1
1,5 d0Distance in slotted holes e4
1,5 d0Distance in slotted holes e3
1,2 d0Edge distance e2
1,2 d0End distance e1
8
Maximum Values for SpacingsEdge and end distances are unlimited, except :
for compression members in order to avoid local buckling and to prevent corrosion in exposed members and;for exposed tension members to prevent corrosion.
9
Local Buckling of Platein compression between the fasteners:
need not to be checked if p1 / t is smaller than 9 ε
according to EN 1993-1-1 using 0,6 p1 as buckling length
t thickness of the thinner outer connected part
yf/235=ε
10
Staggered Rows
minimum line spacing of p2 = 1,2d0
11
Scope of the LectureGeneral Design resistance of individual fasteners
Non-preloading bolts Single lap jointsBearing through packingSlotted holesLong joints RivetsAnchor bolts
Slip-resistant connections using 8.8 or 10.9 bolts Design for block tearing Lug angles Pin connectionsInjection bolts Summary 12
Resistance in Shear in One Shear PlanePlane of shear is going through threads of bolt:
For classes 4.6 a 5.6
( ) M2subRd,v Af6,0F γ=
For classes 8.8 a 10.9
( ) M2subRd,v Af5,0F γ=A s Core area of cross section of bolt
γ M2 Partial safety factor of bolt
f ub Ultimate strength of bolt
13
Resistance in Shear in One Shear PlanePlane of shear is going through shaft of bolt
( ) M2ubRd,v Af6,0F γ=
A Full area of cross section of bolt
γM2 Partial safety factor of bolt
fub Ultimate strength of bolt
14
Resistance in Bearing
p 1e1
d
d
0
Fb.Sdt minimum thickness in one direction
d diameter of boltd0 diameter of holef ub strength of boltf u strength of material
( ) M2uRd.b, tdf5,2F γα=
where α is minimum from formulas
0,1;ff;41d3p;d3e uub0101 -
(0,8 in oversized holes)
15
Resistance in BearingIn oversized holes reduction 0,8
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
e30
L
t
p 1
w pt
1
e1
10
IPE 200
14060
5,6
40
40
445010
V = 110 kNSd
P 10 - 140 x 100M 20 - 5.6
10
R 10 20
16
Bearing of Plate and Bolt
Inner bolt
Outer bolt
17
Bearing Resistance of Bolt Group
For the holes 2:
For the holes 1:
1)Total bearing resistance is based on direct summarising
2)Total bearing resistance is based on smallest of the individual resistances
( ) ( )222
5232520,75240252M
u
M
u
M
uRd,b
ftd,,ftd,,ftd,Fγγγ
α ⋅=⋅⋅+⋅== ∑
( ) ( )222
5261520,40240252M
u
M
u
M
uRd.b
ftd,,ftd,,ftd,Fγγγ
α ⋅=⋅⋅+⋅== ∑
40321
3 0
0
0
1 ,dd,
de
===α
750250125033250
3 0
0
0
1 ,,,dd,
dp
=−=−=−=α
p 1 e 1
F F
Holes 1 Holes 2
p 1 = 3 d 0 e 1 = 1,2 d 0
18
Tensile Resistance
( ) M2sub2Rdt, γAfkF =
A s Area of core of boltγMb Partial safety factorf ub Ultimate bolt strength
k2 = 0,63 for countersunk boltk2 = 0,90 for regular bolt head
19
Punching Shear Resistance
tp plate thickness
dm the mean of the across points and across flats dimensions of the bolt head or the nut, whichever is smaller
Bp,Rd = 0,6 π dm tp fu / γM2
221 dddm
+= 1d
2d
wd dm
20
Combined Shear and Tension
Shank in shear plane
0
0,5
0
Ft,expF t
Experimental tensile resistance / predicted tensile resistance1,0 Treads in shear plane
Fv,expFt
Experimental shear resistance
0,5 1,0
predicted tensile resistance
1F4,1
FFF
t,R
t,S
v,R
v,S ≤+
Owens G.W., Cheal D.B.: Structural Steelwork Connections, Butterworths, 1989.
21
Single Lap Connection with One BoltReduction of bearing resistance
2
51M
uRd,b
tdf,Fγ
≤
30 30
M 16 - 5.6P5 - 60 x 840
58FSd
22
Scope of the LectureGeneral Design resistance of individual fasteners
Non-preloading bolts Single lap jointsBearing through packingSlotted holesLong joints RivetsAnchor bolts
Slip-resistant connections using 8.8 or 10.9 bolts Design for block tearing Lug angles Pin connectionsInjection bolts Summary
23
Shear and Bearing pass through PackingReduction of bolt shear resistance
β
t p
0,5
1,0
0 0,3 d 1,5 d
p
1,0 d
pp 38
9td
d+
=β
01,p ≤β
t p
24
Bearing Resistance in Slotted Holes60% of resistance in circular holes (force perpendicular to the long direction of the slot)
110
25 50 35 10
40 40 8 16
18
8
M 16
110
25 50 35 10
40 40
22 18
M 16
Displacement , mm 0
20
40
60
80
100
120
140
160
0 5 10 15 20 25 30 35 40
Force, F, kN
Slotted holes,
Circular holes, 180
(test 1c-16-1-d+2)
(test 5c-16-1-d+2,5)
8 16 8
45
200
25
Long ConnectionReduction of shear resistance
0
0,2
0,4
0,6
0,8
1
0 15d 65d
β Lt
L j
L j
0,75
ddL j
Lf 20015
1−
−=β
01,Lt ≤β
750,Lt ≥β
26
Scope of the LectureGeneral Design resistance of individual fasteners
Non-preloading bolts Single lap jointsBearing through packingSlotted holesLong connections RivetsAnchor bolts
Slip-resistant connections using 8.8 or 10.9 bolts Design for block tearing Lug angles Pin connectionsInjection bolts Summary
27
Rivet ConnectionsPhilosophy of design was used for bolts (class A)
Bolts spacing's recommendations are coming from rivets
28
Scope of the LectureGeneral Design resistance of individual fasteners
Non-preloading bolts Single lap jointsBearing through packingSlotted holesLong joints RivetsAnchor bolts
Slip-resistant connections using 8.8 or 10.9 bolts Design for block tearing Lug angles Pin connectionsInjection bolts Summary
29
Anchor BoltsThe nominal yield strength does not exceed
when the anchor bolts act in shear 640 N/mm2
otherwis not more than 900 N/mm2
For bolts with cut threads reduction by a factor of 0,85
30
Scope of the LectureGeneral Design resistance of individual fasteners
Non-preloading bolts Single lap jointsBearing through packingSlotted holesLong joints RivetsAnchor bolts
Slip-resistant connections using 8.8 or 10.9 bolts Design for block tearing Lug angles Pin connectionsInjection bolts Summary
31
Slip-resistant Connectionsusing 8.8 or 10.9 Bolts
F
Fs.Rd
p.Cd
( ) Cd,pM3,sersRd.s, FnkF γμ=
Fp,Cd is design prestressing force of bolt ub A s),μ friction coefficient
n number of friction planesks coefficient corresponding to clearance of hole
(= 0,7 f
Prestressing force
32
Friction Coefficient μTests
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.
0,2D cleaned (EN 1090)0,3C cleaned (EN 1090)0,4B blasted (EN 1090)0,5A blasted, metal spraying (EN 1090)
Slip factor µClass of friction surfaces
33
Hole Size Coefficient ks
0,63Long slotted holeswith the axis of the slot parallel to the direction of load transfer
0,76Short slotted holes with the axis of the slot parallel to the direction of load transfer
0,7Long slotted holes with the axis of the slot perpendicular to the direction of load transfer
0,85Oversized holes or short slotted holes with the axis of the slot perpendicular to the direction of load transfer
1,0Normal holes
ksDescription
34
Combined Tension and Shear
2
80
M
Ed,tC,ps )F,F(nk Fs,Rd
γμ −
=
F b F p
F b
F t
δ b
δ b,ext
δ p,ext δ p
Δ
F j
F j Δ
elongation of the bolt
bolt
plate shortening
external
total bolt force
tensile force preload
35
Scope of the LectureGeneral Design resistance of individual fasteners
Non-preloading bolts Single lap jointsBearing through packingSlotted holesLong joints RivetsAnchor bolts
Slip-resistant connections using 8.8 or 10.9 bolts Design for block tearing Lug angles Pin connectionsInjection bolts Summary 36
Block TearingBlock 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.
NEd
N Ed
NEd
N Ed
37
Test
Orbison J.G., Wagner M. E., Fritz W.P.: Tension plane behavior in single-row bolted connections subject to block shear, Journal of Constructional Steel Research, 49, 1999, s. 225 – 239. 38
FE Model
Topkaya C.: A finite element parametric study on block shear failureof steel tension members, Journal of Constructional Steel Research, 60 , 2004, s. 1615 – 1635, ISSN 0143-974X.
Rupture
39
Design ModelSymmetric bolt group subject to concentric loading
Veff,1,Rd = fu Ant / γM2 + (1/√3) fy Anv / γM0
Ant net area subjected to tensionAnv net area subjected to shear
Eccentric loadingVeff,2,Rd = 0,5 fu Ant / γM2 + (1/√3) fy Anv / γM0
40
40
3525
8 x M16; 70
P10; 1.4401
L - 100 x 100 10
30 + 7 x 30 +30
70
100
70materiál 1.4401
240
60
35
240
Worked Example - Angle
In plate (staggered rows)
In angle (staggered rows)
=+=M0
nvy
M2
ntuRdeff,1, 3
1γAf
γAfV ( ) ( ) kN48140972
101110921862402220
31
1025110923553050
33 =+=×
××−×−×××+
×××−××
=,,
,
=+=M0
nvpy,
M2
ntpu,Rdeff,2, 3
10,5γAf
γAf
V( ) ( ) kN27420470
1011109183240220
31
10251101896053050
33 =+=×
×−×−××+
××−××
=,,
,
41
Single Lap ConnectionReduction of bearing resistance
2
51M
uRd,b
tdf,Fγ
≤
e2
d
t
( )N
e d t fu Rd
u
M.
, ,=
−2 0 0 52 0
2γ
42
Single Lap Connectionp1
p1 p1
p1
p1 p1
NA f
u Rdnet u
M. =
β
γ2
2
NA f
u Rdnet u
M. =
β
γ3
2
≤ 2,5 d0≥ 5 d0
0,70,53 and more bolts β3
0,70,42 bolts β2
Pitch p1
Reduction factors
43
Worked Example – Fin Plate
45
70
70
45
3 x M20, 8.8
50 50
35
60
10
IPE 300S235
meteriál S235
5
P10 - 230 x 110HEA 200S235
230
= 100 kNV Sd
44
Worked Example – Fin Plate, Shear Resistance
In beam web
80
70
70
5050
45
70
70
45
230
kN19901
517112353
1251
927636050=××+
××=
,,
,,,
M0
nvb1y,
M2
b1u,Rd,11 3
150γγAf
Af,V += nt
45
Worked Example – Fin Plate, Tying Resistance
In beam web
70
70
5050
45
70
70
45
M0
nvb1y,
uM,
ntb1u,u,6Rd, 3
1γγAf
AfN += kN298
018553235
31
116681360
=××+×
=,
,,
,
46
Scope of the LectureGeneral Design resistance of individual fasteners
Non-preloading bolts Single lap jointsBearing through packingSlotted holesLong joints RivetsAnchor bolts
Slip-resistant connections using 8.8 or 10.9 bolts Design for block tearing Lug angles Pin connectionsInjection bolts Summary
47
Lug Angles
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. 48
Scope of the LectureGeneral Design resistance of individual fasteners
Non-preloading bolts Single lap jointsBearing through packingSlotted holesLong joints RivetsAnchor bolts
Slip-resistant connections using 8.8 or 10.9 bolts Design for block tearing Lug angles Pin connectionsInjection bolts Summary
49
Pin ConnectionsAnalysis
As bolt (shear, bearing)As beam (bending)Combination of shear and bending
FSd
d = 30
t1 = 10
c = 1t2 = 18
d3 = 20
t = 101
c = 1
t1cc
t1 t2
MSd
50
Design of PinGiven thickness t
Given geometry323
22
0000 dft
Fc:
dft
Fa
y
MEd
y
MEd +≥+≥γγ
t,d:f
F,t
y
MEd 5270 00 ≤≥
γ
51
Analysis of Pin - ShearResistance of one shear area of pin in shear
( ) SdSd.vMpupRd.v F5,0FfA6,0F =≥γ=
FSd applied forcef up strength of pinγMp = 1,45 partial safety material factor
A Cross sectional area of pin
52
Analysis of Pin - Bending
t1cc
t1 t2
MSd
Resistance of pin in bending( ) ≥γ= MpypeRd fAW8,0M l ( )( )1SdSd t2c4t8FM ++=
FSd applied force
f yp yield point of pin
γMp = 1,45 partial safety material factorA cross sectional area of pin
W del = π 3 32 cross sectional elastic modulus of pin
53
Analysis of Pin –Combination of Bending and Shear
t1cc
t1 t2
MSd
Stresses due to bending and shear:
( ) ( )M M F FSd Rd v Sd v Rd2 2 1+ ≤, ,
54
Analysis of Pin - Bearing
Bearing stress of plate and pin( ) MpyRd,b fdt5,1F γ= pro yyp ff ≥ a tt2 1 ≥
f y yield point of platesf yp yield point of pin
γMp = 1,45 partial safety material factor
55
Analysis of Pin - ServiceabilityReplaceable pinthe contact bearing stress should satisfy σh,Ed ≤ fh,Rd
fh,Ed = 2,5 fy / γM6,ser
d the diameter of the pin;d0 the diameter of the pin hole;FEd,ser the design value of the force to be transferred in bearing,
under the characteristic load combination for serviceability limit states
td)dd(FE
, ser,EdEdh, 2
05910−
=σ
56
Scope of the LectureGeneral Design resistance of individual fasteners
Non-preloading bolts Single lap jointsBearing through packingSlotted holesLong joints RivetsAnchor bolts
Slip-resistant connections using 8.8 or 10.9 bolts Design for block tearing Lug angles Pin connectionsInjection bolts Summary
57
Injection Bolts
Bolts of class 8.8 or 10.9The design ultimate shear load of any bolt in a Category APreloaded injection bolts should be used for Category B and C connections
σ
σσσ
σ
σ
1
112
2
2
1
2
2
1
2
t
t
t
t1.0
1,01,33
2.0 /
β
t
58
σ
σσσ
σ
σ
1
112
2
2
1
2
2
1
2
t
t
t
t1.0
1,01,33
2.0 /
β
t
Bearing Strength of an Injection Bolt
ß coefficient depending of the thickness ratiofb,resin bearing strength of the resin tb, resin effective bearing thickness of the resinkt 1,0 for serviceability limit state
1,2 for ultimate limit stateks 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
4M
sinre,bsinre,bstresinRd,b,
ftdkk F
γβ
=
59
Scope of the LectureGeneral Design resistance of individual fasteners
Non-preloading bolts Single lap jointsBearing through packingSlotted holesLong joints RivetsAnchor bolts
Slip-resistant connections using 8.8 or 10.9 bolts Design for block tearing Lug angles Pin connectionsInjection bolts Summary 60
SummaryConnections made with bolts, rivets or pins
in Chapter 3 of EN 1993-1-8Non-preloaded boltsPreloaded bolts – preload (0,7 fub)Injection bolts (replacement of rivets;
bolts 8.8 and 10.9)Pins (including serviceability)
1
Basics of structural joints(Structural Joints Connecting Open Sections)
Lessons Connection Design according to EN 1993-1-8
Prof. František Wald
2
List of Lessons at Seminar1. Introduction2. Bases of design according to EN 1993-1-83. Welded connections4. Bolted connections5. Basics of structural joints6. Design of simple connections 7. Column bases8. Fire design of connections, EN 1993-1-29. Seismic design, EN 1998-1-1
3
Scope of the LectureGeneral Component methodBasic componentsAssembly
ResistanceStiffnessRotation capacity
M-N interactionSummary
4
Different ApproachesExperimentationCurve fittingFinite element analysisSimplified analytical models – Component Method
M
φ
Experiment
Function h
t
lb
a
t M 5
53
31
1 )kM(C)kM(C)kM(C ++=φ
5
Design curve
Joint resistance
M j, Rd
Deformation capacity
φj,Cd
Initial stiffness Sj, ini
Elastic
2/3 M j, Rd limit
φ
Experimental curve
Rotation, , mrad
M, moment, kNm
Moment-Rotation CharacteristicRotational stiffnessMoment resistanceRotation capacity
6
Scope of the LectureGeneral Component methodBasic componentsAssembly
ResistanceStiffnessRotation capacity
M-N interactionSummary
7
Procedure
Web panel in shear
Connection
Components in tension
Column web in tension
Column web in compression
Components in compression
Joint
Decomposition of jointComponent descriptionJoint assembly
ClassificationRepresentationModelling in analyses 8
Rotational Capacity
0
M
φ
j.RdM
φ el φ u φ Cd
rotational capacity φ pl
Bending moment, kNm
Rotation, mrad
Bilinear model Experimental curve
Plastic
capacityRotationalof joint
9
Decomposition of Joint
Unstiffened column web in shearUnstiffened column web in compressionBeam flange in compressionColumn flange in bendingBolt row in tensionEnd plate in bendingUnstiffened column web in tension
10
Background ReferencesZoetemeijer 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 Bolted 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 Connection based on Test results -Test and Analysis, Ref. No. 6-83-23, Steven Laboratory, Delft, 1983.
11
Practical Applicationof the Component Method
Design tablesGreen bookBlue book
Computer programs
Simplified hand calculation
12
Spring ModelsParallel configuration
Serial configuration
F 1
21
2
d
Fu = F1.u + F2.u k = k1 + k2 δ = min (δ1; δ2)
F 1 21
2
d
Fu = min (F1.u; F2.u) 1 / k = 1 / k1 +1 / k2 δ = δ1 + δ2 .
13
Scope of the LectureGeneral Component methodBasic componentsAssembly
ResistanceStiffnessRotation capacity
M-N interactionSummary
14
Description of Basic Components
The structural properties of basic joint components are described in Chapter 6 of EN 1993-1-8.e.g.
Column web panel in shear Column web in transverse compression Column web in transverse tensionColumn flange in bending End-plate in bending Flange cleat in bending
etc.
VEd
VEd
Fc,Ed
Ft,Ed
Ft,Ed
Ft,Ed
Ft,Ed
15
Bolts in TensionAnalytical model
Stiffness coefficient
Resistance, see boltsDeformation capacity - britle
Ft,Ed
s
bEd,tb AE
LF2
=δ
b
s
b
Ed,tb L
A,EF
k 02==δ
b
sb L
A,kk 6110 ==
16
End-plate in Bending
Ft,Ed
Analytical modelStiffness coefficient
IEmF Ed,t
p 3
3
=δ
3
3
3
3
3 5012233
mtL
,m
tL
mFEIEF
EF
k ini,eff
ini,eff
Ed,t
Ed,t
p
Ed,tp ====
δ
effeff.ini L 1,7 L =
3
3
654 850m
tL,kkkk effp ====
17
End-Plate Resistance
Ft,Ed
By equivalent T-stub in tension
Deformation capacity - ductile
n m
t
F
BB
Leff
2
18
Failure Modes
Mode 1 - Plate failure
Mode 2 - Plate and bolts failure
Mode 3 - Bolts failure
19
Bolt head / washer size influence
Mode 1 only
u
n m
F/2 F/2
Q/2
ϕ
F/4
Q Q
Q/2
F/4
Q/2
F/4
Q/2
F/4
d w d w
C
ϕ
C
un m
F/2 F/2
Q
F/2
Q
F/2
Q Qϕ ϕ
20
Effective LengthCircular failure
Single boltBolt group
Another failureSingle boltBolt group
21
Circular Failure
Virtual workon cone deformation
mL cp,eff π2=
⇒
2 r
F ϕ
r = m
δ
r = n
F
F
F
F
ϕ
x
r
δ
αα
ααα
ϕ r´/2
ϕ/2
ϕ/2
22
Bolt in Corner
m L op,eff α=
In EN 1993-1-8 graph only
emm+
= 22λ
emm+
=1λ
0,90,0
0,2
0,4
0,6
0,8
1,0
1,2
1,4
0,0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8
λ 2
λ1
= 8 p2 5,5 4,75 4,45α
23
Bolt at Oversize
bp
Yield lines
e mx
e
mx e
mx
e mx
wWeld
24
T stub Position
25
Column Flange with Backing Plates
Increase of resistance Mode 1only
hbp
ebp
ebp
m
MM F Rd,bpRd,,pl
RdT,1,24 1 +
=
02
1250 Myf,effRdpl,1, /ft,M γlΣ=
02
1250 Mbp,ybp,effRdbp, /ft,M γlΣ=
26
Flange Cleat in BendingAs equivalent T-stub flange
27
Influence of Gapg ≤ 0,4 ta g > 0,4 ta
Effective length ℓeff = 0,5ba
ra memin
0,8 r a
g 0,4 t a≤
ra memin
0,5 t a
g 0,4 t a>
ba
28
Another Componentssee EN 1993-1-8
29
Scope of the LectureGeneral Component methodBasic componentsAssembly
ResistanceStiffnessRotation capacity
M-N interactionSummary
30
Design ResistanceWelded connection
zFM Rd,tRd,j =
zFt,Rd
Fc,Rd
M j,Rd
31
Design ResistanceBoted connection – one bolt row
∑= i iRd,tiRd,j zFM
zz
Ft.Rd
Fc.Rd
Ft.Rd
Fc.Rd
32
Simplified Lever Arm
z zz z z
33
Ft1.Rd F
t1.RdF
t1.Rd
More Bolt Rows - Firs Bolt Row (start from top)
Ft1.Rd
Ft1.Rd F
t1.Rd
End plate in bending
Column web in tensionColumn flange in bending
Resistenceoffirst bolt row
Beam flange in compression
Column web in compression
Colum web in shearLimits byshear and compressed part
34
More Bolt Rows – Second Bolt Row
Ft1.Rd
Ft2.Rd
Ft1.Rd
Ft2.Rd
Ft1.Rd
Ft2.Rd
Ft2.Rd Ft2.Rd Ft2.Rd
Ft2.Rd
Ft1.Rd
Ft2.Rd
Ft1.Rd
Ft2.Rd
Column web in tensionColumn flange in bendingColumn web in tension
Resistance of both bobt rows
End plate in bendingColumn web in tensionColumn flange in bending,
Resistance ofsecond bolt row
Beam flange in compression
Column web in compression
Colum web in shearLimit By shear and compressed part
35
More Bolt Rows - Third Bot RowTaking into account bolt rows groupsEtc.
Part in compression
Part in tension
Ft1.Rd
Ft2.Rd
Ft3.Rd
Ft1.Rd
Ft2.Rd
Ft3.Rd
Ft2.Rd
Ft3.Rd
Ft2.Rd
Ft3.Rd
Ft2.Rd
Ft3.Rd
Ft3.Rd
Ft1.Rd
Ft2.Rd
Ft3.Rd
Ft1.Rd
Ft2.Rd
Ft3.Rd
Ft1.Rd
Ft2.Rd
Ft3.Rd
36
Scope of the LectureGeneral Component methodBasic componentsAssembly
ResistanceStiffnessRotation capacity
M-N interactionSummary
37
Rotational StiffnessRotatinal stiffness Sj = M / φ
Deformation or a component
Rotation in jointJoint with more springs
EkFi
ii =δ
zi
i
j
∑=
δφ
∑∑∑∑→====
iii
i
i
i
i
j
jini.j
k
zE
k
zE
kEF
zF
z
zFMS 111
222
μδφ
φ
38
Design curve
Joint resistance
M j, Rd
Deformation capacity
φj,Cd
Initial stiffness
Sj,
ini
Elastic
2/3 M j, Rd limit
φRotation, , mrad
M, moment, kNm
Shape by stiffness ratio factor
Shape Stiffness Ratio FactorFrom curve fitting
1≥⎟⎟⎠
⎞⎜⎜⎝
⎛==
ψ
κμRd,j
Sd
j
ini,j
MM
SS
39
More Components
Mj z
δ
φφ1 φ2 φ3
z z1 2 φ
40
Equivalent stiffness
Lever armz
z
1
4
∑∑
=
iii,eff
iii,eff
zk
zkz
2
∑=
i i
eff
k
k 11
z
zkk i
ii,eff
eq
∑=
41
Scope of the LectureGeneral Component methodBasic componentsAssembly
ResistanceStiffnessRotation capacity
M-N interactionSummary
42
Rotation CapacityFor platic global analysesFor basic safety
Ductile componentsPlate in bendingColumn web in shear
Brittle componentsBots, welds
0,0
M
φ
j.RdM
φ el φ u φCd
φCd
43
Upper Limits for MaterialIn the US standard only
δ
F
δCd,2δCd,1
δ
F
δ Cd,2δ Cd,1
Brittle Ductile
Brittle
Ductile
44
In EN 1993-1-8Deem to satisfy criteria
Welded jointsUnstiffnedUnstiffned in tension + Stiffened in compression + No shear influece
Boted jointsPlate failureEnd plate/column flange thickness
bcmin,Cd h/h,0250=φ
yub f/fd,t 360≤
0150,min,CD =φ
45
Scope of the LectureGeneral Component methodBasic componentsAssembly
ResistanceStiffnessRotation capacity
M-N interactionSummary
46
M-N InteractionFor most portal frame connections (pitched rafters)In EN 1993-1-8
Limit 5% of normal force resistance of connected element Linear interaction
Component method
1≤+Rd,j
Sd
Rd,j
Sd
MM
NN
47
Example
MV
N
Sd Sd
Sd
Moment,
Normal force, kN
Linear interactionComponent method
5 % error
kNm
48
Application of EN 1993-1-8 Procedure
N
FF
F1,t
2,t
3,t
j,t,M,Rd
et
N
F
F
2,c
1,c
j,c,M,Rd
et
Moment
Normal force
Linear interaction
Component method
M
j.t.N
N
j,c,M,RdN
j,t,M,Rd
N
j,t,M=0,Rd Linear interactionN
j,c,M=0,Rd
M
j.c.N
1≤+Rd,j
Sd
Rd,j
SdMM
NN
49
Component Method - Resistance
As for base plates
N SdM Sd
F t.Rd
z
zt
zc
Fc.RdActive part
Neutral axis
Centre of the part in tension
Centre of the part in compression
50
Stiffness
NSd
MSd
NSd
MSdz
Ft.Rd
z
zt
zc
Fc.Rd
Fc.t.Rd
zc.t
zc.b
Fc.b.Rd
Bolts and compressed part Two compressed parts
Simplification to two springsBoltsCompressed part – in centre of flage
51
Evaluation on Tests
10 20 Moment,100
200
-200
-100
Normal force, kN
SN 1500
SN 100000
InteractionComponent method
kNm
Test
-10
52
M - φ Diagram Praha Test
0
5
10
15
20
25
30
0 0,01 0,02 0,03 0,04
Moment, kNm
Rotation, rad
Test SN 1500Prediction by component method
Prediction of resistanceby interaction
53
Evaluation on Coimbra Tests
Moment,
Normal force, kN
Interaction
Component method
-400
0
400
800
-50 050
kNmEE1EE2
EE3EE4
EE5
EE6EE7Experiments
54
M - φ Diagram Coimbra Test
0
20
40
60
80
100
120
0 0,01 0,02 0,03 0,04
Moment, kNm
Rotation, rad
Test EE7
Prediction by component method
Prediction of resistanceby interaction
0,060,05
1
Design of Simple Connections (of Open Sections)
Lessons Connection Design according to EN 1993-1-8
Prof. František Wald
2
List of Lessons at Seminar1. Introduction2. Bases of design according to EN 1993-1-83. Welded connections4. Bolted connections5. Basics of structural joints6. Design of simple connections 7. Column bases8. Fire design of connections, EN 1993-1-29. Seismic design, EN 1998-1-1
3
SSEDTA LectureNew and Flexible Approach to Training for Engineers in Construction
Leson 16 Design of Simple JointsDesign of Simple Joints
Access STEEL information tool on internet
4
List of Lessons related to Connection DesignFlow Charts
Simple connections - fin platesSimple connections - end platesColumn splices for both axial load & momentColumn bases (axial load only)
Non-conflicting Complementary InformationDesign model for simple end plate connectionsA: Detailing guidanceB: Shear resistanceC: Tying resistanceDesign model for simple fin plate connectionsA: DetailingB: Shear resistanceC: Tying resistanceDesign model for simple Column splices (non-bearing)Initial sizing for non-bearing splicesDesign model for simple Column bases - axially loaded
Passive examplesBeam to beam fin plate connectionBeam to column end plate connectionColumn splice (non-bearing)Column base, axially loadedColumn splice (bearing)
5
Example – Fin PlateFlow chart
6
7 8
Example – Fin PlateSubject to shear
1. Fin plate2. Supported beam3. Column4. Supporting beam
1 1 13 3
4
2 2 2
9
Example – Fin PlateMode of failure - subject to shear
VRd,12Supporting column web or supporting beam web (punching shear)
VRd,11Beam web in shear (block shear)VRd,10Beam web in shear (net section)VRd,9Beam web in shear (gross section)VRd,8Beam web in bearingVRd,7Fin plate in buckling (LTB)VRd,6Fin plate in bendingVRd,5Fin plate in shear (block shear)VRd,4Fin plate in shear (net section)VRd,3Fin plate in shear (gross section)VRd,2Fin plate in bearingVRd,1Bolts in shear
10
Example – Fin PlateDuctility requirements
not guided by bolt shear failure
11
Example – Fin PlateRotation capacity requirements
1. Given rules in initial design
or2. Limit of hight and calculate required rotation
rthh b1f,bp 22 −−≤
requiredavailable φφ >
2,b
p
1,b 1
1
1
1
2
e
e
h
e
p
p
e e
z
a
gh
e h
gv
b p
600≤b1h600>b1h 60402012010
50401010010
Fin plate edge distancee2 (mm)
Beam edge distance e2,b (mm)
Horizontal gapgh (mm)
Fin plate width bp (mm)
Fin plate thicknesstp (mm)
Depth of supported beam
hb1 (mm)
12
Example – Fin PlateSubject to tying forces
1. Fin plate2. Supported beam3. Column4. Supporting beam
1 11
2 2 2
3 3
4
13
Example – Fin PlateMode of failure – subject to tying
NRd,u,8Supporting column web in bendingNRd,u,7Beam web in tension (net section)NRd,u,6Beam web in tension (block tearing)NRd,u,5Beam web in bearingNRd,u,4Fin plate in tension (net section)NRd,u,3Fin plate in tension (block tearing)NRd,u,2Fin plate in bearingNRd,u,1Bolts in shear
14
SummaryDesign of simple connections not described in EN 1993-1-8
TablesGreen book UKBlue book GermanyECCS TC10 document (in preparation)
Access STEEL materials on internet
15
List of Lessons at Seminar1. Introduction2. Bases of design according to EN 1993-1-83. Welded connections4. Bolted connections5. Basics of structural joints6. Design of simple connections 7. Column bases8. Fire design of connections, EN 1993-1-29. Seismic design, EN 1998-1-1
16
Thank you for your attention
1
Structural Steelwork EurocodesStructural Steelwork Eurocodes
Design of Simple JointsDesign of Simple Joints
2
Simple JointsSimple Joints
Frames are traditionally analysed assuming joints to be either:
– Pinned.
– Rigid.
However few joints meet these ideals.
3
DesignDesign Considerations of JointsConsiderations of Joints
Rigid Joints:– Expensive to fabricate and construct.
Real Pin Joints:– Also expensive
Simple Joints:– Need to be flexible
4
EC 3 RequirementEC 3 Requirement
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.”
5
Joint RequirementsJoint Requirements
Joints must:– Transfer actions.– Accept required rotations.
6
Joint PropertiesJoint Properties
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.
7
Stiffness RequirementStiffness Requirement
S j,ini not greater than: 0,5 E Ib / Lb.
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.
8
Strength RequirementStrength Requirement
Depends upon the members connected.
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.
9
Maximum Moment ResistanceMaximum Moment Resistance
Mpc is fully plastic moment of resistance of column.Mpb is fully plastic moment of resistance of beam.
Figure 1: Maximum moment resistance requirement for simple joints
If Mpb < 2Mpcthen Mj,Rd = 0.25Mpb
If Mpb > 2Mpcthen Mj,Rd = 0.25*2*Mpc
Mpb
Mpc
MpcMpc
Mpc
Mpb
10
Rotation CapacityRotation Capacity
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.
11
Effect of Gap ClosureEffect of Gap Closure
φ
Figure 2 : Effect of gap closure
M
Contact between beamflange and column face
M
φ
12
PracticalitiesPracticalities
Many joints currently assumed to operate as simple joints transfer moments in excess of EC3 limits.
Resulting designs function satisfactorily.
Supported by extensive research.
13
Transfer of ForcesTransfer of Forces
Joints likened to links in a chain.
Strength determined by weakest link.
Principal transfers by:– Welding.– Bolting.– Riveting,(occasionally ).
14
Top and seat cleats(major and minor axes
Beam to Column Joints Beam to Column Joints Example 1Example 1
Seat and stability cleats (major and minor axes)
15
Single web cleat (major axis:bolted to beam and column)Welded fin plate: (minor axis:bolted to beam, welded to column.
Beam to Column Joints Beam to Column Joints Example 2Example 2
Double web cleats (minor axis: Welded to beam, bolted to column).Tab plate: (major axis: welded to beam, bolted to column).
16
Beam to Column Joints Beam to Column Joints Example 3Example 3
Shear plate (major axis) Shear plate (major axis)
17
Typical Beam to Beam JointTypical Beam to Beam Joint
Figure 4:Beam to beam
connections
2.1.2 Should any tying forces need to be considered ( as is the case in theU.K.NAD). Then the connection must also be checked for such action whichwill involve consideration of the following potential failure modes, rememberingthat it will often be necessary to combine the axial and the shear forces to obtain a resultant action.
Double notched end plate connection
Supported beam
Single notched angle connection
Supporting beam
18
Simple Web Angle Connection Simple Web Angle Connection
19
Transfer of ForcesTransfer 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.
20
Simple Web Angle ConnectionSimple Web Angle Connection
a1
Lv
a3
a2
21
Transfer of ForcesTransfer of 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.
22
Checks Needed for Tying Checks Needed for Tying ForcesForces
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.
23
Other Detailing GuidanceOther Detailing Guidance
Minimum end distance.Minimum edge distance.Maximum end and edge distances.Minimum bolt spacing.Maximum bolt spacing.
24
SummarySummary
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.
1
Column Bases
Lessons Connection Design according to EN 1993-1-8
Prof. František Wald
List of Lessons at Seminar1. Introduction2. Bases of design according to EN 1993-1-83. Welded connections4. Bolted connections5. Basics of structural joints6. Design of simple connections 7. Column bases8. Fire design of connections, EN 1993-1-29. Seismic design, EN 1998-1-1
Scope of the LectureBasis of designComponents
– Base plate in bending and bolt in tension– Base plate and concrete in compression– Anchor bolt in shear
Assembly– Resistance– Stiffness – Pre-design
Classification Worked examplesSummary
Background MaterialsENV 1993-1-1– Annex L (1992)– Annex A2 – Design of Joints (1992, 1999)
COST C1 - Semirigid connections (EU project, finished 1999)
Fixing by Base Plate
Base plate in bending
and anchor bolts in tension
Column web in compression
Anchor bolts in shear
Base plate in bending
and concrete in compression
Component Method
Major components
Baseplate in bending Column flange and web Baseplate and concrete Anchor boltin compressionanchor bolts in tensionin compression in shear
Scope of the LectureBasis of designComponents
– Base plate in bending and bolt in tension– Base plate in bending and concrete in compression– Anchor bolt in shear
Assembly– Resistance– Stiffness – Pre-design
Classification Worked examplesSummary
Base-plate in bendingand anchor bolts in tension
eff
Column flange
Base plate
F
t
e m
l
Contact of Edge of T stub
nm
F
Q = 0
Θpδ b
δb = Θp n
Q = 0
b3eff
s3
lim.b LtL
Am82,8L ><=
Lbf
L
d
beL b
Lbe ≅ 8 d
Embedded Anchor Bolt
CEB documents for anchor bolts resistance
0
20
40
60
80
100
120
140
160
180
0 0,2 0,4 0,6 0,8 1 1,2 1,4 1,6Deformation, mm
Force, kN
Experiment W13/98Experiment W14/97Prediction
5010
40
40
315 3
65
9595
P10 - 95 x 95
P6 - 40 x 50 5
24 - 355
10
φ
F
B
Rd.3
t.RdB
t.Rd
F
B
Rd.1
B
Q Q
e
n m
Q Q
B t.RdBt.Rd
FRd.2
Mode 3 Mode 1 Mode 2a) b) c)
F
B B
Rd.1*End plate – contact or no contact
Base plate – no contact
0
0,2
0,4
0,6
0,8
1
0 0,5 1 1,5 2 2,5
Mode 1
Mode 2Mode 3
Mode 1*
F B/ Σ t.Rd
4 eff M pl.Rd / Σ Bt.Rdl
ResistanceF
B B
Rd.1*
m´ML2
F Rd.pleff1.Rd =∗
m = 32
W97-020
50
100
150
200
250
300
350
0 2 4 6 8
Force, kN
Deformation, mm
Simplified prediction
Complex calculationm = 67
W97-12
0
50
100
150
200
250
300
350
0 2 4 6 8
Force, kN
Deformation, mm
Simplified prediction
Experiment
Complex calculation
Stiffness
No prying
kL t
mpeff=
0 425 3
3
,k
ALb
s
b= 2 0,
Prying accured
kL t
mpeff=
0 85 3
3
,k
ALb
s
b= 1 6,
Effective length of T stub
e m
Prying occured( )e25,1m4m21 +−= αl
m22 π=l
( )211,eff ;minL ll=
12,effL l=
No prying( )e25,1m4m21 +−= αl
m42 π=l
( )211,eff ;minL ll=
12,effL l=
bp
mx
ex
e w e
Pryingl 1 = 4.mx+1,25 exl 2 = 2 π mx
l 3 = 0,5 bpl 4 = 0,5 w + 2 mx + 0,625 exl 5 = e + 2 mx + 0,625 exl 6 = e2mx +π
( )6543211,eff ;;;;;minL llllll=
( )54312,eff ;;;minL llll=
l 1 = 4.mx+1,25 exl 2 = 4π mx
l 3 = 0,5 bpl 4 = 0,5 w + 2 mx + 0,625 exl 5 = e + 2 mx + 0,625 exl 6 = e4m2 x +π
( )6543211,eff ;;;;;minL llllll=
( )54312,eff ;;;minL llll=
No prying
Effective Length for Hollow Sections(not in EN 1993-1-8)
m
b
m
b
aac
bc
eaeb
m
mL .eff π=1
2bL 2.eff =
( ) ( )2222
3 8 ccba
ba.eff bbaam
eeee
L −+−+
=
( ) ( ) 2222
2 bacc ee
bbaam +−
−+−=
)L;L;L;L;L(minL 5.eff4.eff3.eff2.eff1.effeff=
2aL 4.eff =mL .eff π=5
(a)
Scope of the LectureBasis of designComponents
– Base plate in bending and bolt in tension– Base plate and concrete in compression– Anchor bolt in shear
Assembly– Resistance– Stiffness – Pre-design
Classification Worked examplesSummary
Base plate in bendingand concrete in compression
Flexible base plate3D behaviour – concrete in crushing
c
f j
L
Column flange
Base plate
F
t
c tw
Sd FRd
Concrete 3D Resistance in Crushing(the same as EN 1992-1-1)
Joint coefficient
Effective width
Effective width
babak 11
j =
⎪⎪⎭
⎪⎪⎬
⎫
⎪⎪⎩
⎪⎪⎨
⎧
+
+
=
1
r
1
b5ha
a5a2a
mina aa1 ≥
⎪⎪⎭
⎪⎪⎬
⎫
⎪⎪⎩
⎪⎪⎨
⎧
+
+
=
1
r
1
a5hb
b5b2b
minb bb1 ≥
a
h
a a
bb
b
1
r
1
r
t
jM
y
ff
tc03 γ
=
ydftM 2
61
=′
2
21 cfM j=′
yj ftcf 22
61
21
=
jM
y
ff
tc03 γ
=
ydftM 2
61
=′
2
21 cfM j=′
yj ftcf 22
61
21
=
c c c
cc
M
t c c
Effective width
Elastic resistance ensuring small deformations, to unit length
Bending moment to unit length
Equivalent length of cantilever c
Effective width
Contact Area
Aeq
Ap A
c c
c
c
c
c
Comparison to FE simulation
0,1
Vertical deformation along the block height
foot of the concrete block
top of the concrete block
Vertical deformation at the surface, mm
elastic deformation of the whole block
predicted value
0,10
deformation at the axis
elastic deformation
deformation at the edge
Vertical deformation, mm
0,0
edge axis
}local deformation under plateF
δglob
δedge
δaxis
Stiffness
δ E Ip
xcfl
δα
rr
c r
F aE A
= deformation of elastic hemisphere
δ rc r
FE L a
=0 85,
E275,1LaE
E85,0*5,1LaE
EFk el.eqcel.eqc
c ===δ
a eq.el = t w + 2,5 t 0Mj
ywweq.str f3
f t 2 + t = c 2 + t = a
γ≈
Comparison to Experiments
0
200
400
600
800
1000
1200
1400
1600
1800
0 0,1 0,2 0,3 0,4 0,5 0,6 0,7 0,8 0,9Deformation, mm
Force, kN
Concrete and groutConcrete
Experiment
Prediction based on local and global deformation,
Prediction based on local deformation only
Calculated strengthL
F
δ
t t w
Grout
lower nut
packings
β j = 2 / 3
f c.g ≥ 0,2 f ct g ≤ 0,2 min (a ; b)t g ≥ 0,2 min (a ; b)
h
ttg
gt
45o
tg
g45 o tt
Scope of the LectureBasis of designComponents
– Base plate in bending and bolt in tension– Base plate in bending and concrete in compression– Anchor bolt in shear
Assembly– Resistance– Stiffness – Pre-design
Classification Worked examplesSummary
Components in Shear Anchor Bolt in Shear
Format as bolts in shear
Fh
δh
0
Fh
δ h
Resistance in bending and shearReduce resistance in tension
Resistance in tension
4.6
Mb
subRd.v
Af375,0Fγ
=
5.6
Mb
subRd.v
Af250,0Fγ
=
Scope of the LectureBasis of designComponents
– Base plate in bending and bolt in tension– Base plate in bending and concrete in compression– Anchor bolt in shear
Assembly– Resistance– Stiffness – Pre-design
Classification Worked examplesSummary
Resistance
Plastic design – force equilibriumComplex shape of contact area
∑−= Rd.tjeffRd FfAN
cjeffbRd.tRd rfArFM += ∑ .
MN Rd
r b
F fj
r c
Rd
t.Rd
Aeff
∑
active part
∑-= Rd.tjeffRd FfAN
cjeffbRd.tRd rfArFM += ∑
Interaction diagram
∑−= Rd.tjeffRd FfAN
cjeffbRd.tRd rfArFM += ∑ .
M
NN0Ft.Rd
compression
MM , N2 2
M , N1 1
tension
M=0
N=0
Scope of the LectureBasis of designComponents
– Base plate in bending and bolt in tension– Base plate and concrete in compression– Anchor bolt in shear
Assembly– Resistance– Stiffness – Pre-design
Classification Worked examplesSummary
History of LoadingMoment
Rotation
MRd
SdS j.ini
Plastification of one component
Anchor bolts in tension and one flange in compression
Nonlinear part of the curve
Non-proportional loading
Proportional loading
0 Normal force
MomentNon-proportional
Proportional
resistance
e N0
0
Column base
loading
loading
Simplified contact area
∑−= Rd.tjeffRd FfAN
cjeffbRd.tRd rfArFM += ∑ .
T
MNSd
Sd
z z c
z
F Ft c
c c
cc c c
kk
kp
kbc
tk c k c
c
c
φ
⎧
⎨⎪
⎩⎪
⎟⎟⎟⎟
⎠
⎞
⎜⎜⎜⎜
⎝
⎛
+−=
SdSd
t
Rd.c
SdSd
c
Rd.TRd
N/Mz1
zF;
N/Mz1
zFminM
Stiffness
Simplified contact area
∑−= Rd.tjeffRd FfAN
cjeffbRd.tRd rfArFM += ∑ .
c c
cc c c
kk
kp
kbc
tk c k c
c
c
⎧
⎨⎪
⎩⎪
MSd / NSd = konst. xc <NSd / MSd < ∝
∑−=
i
2
SdSd
SdSdj
k1
zEN/M
N/MSμα
tc
ttcc
kkkzkz
+−
=α
( )μ γ= 1 52 7
,,
γ =+
+
1 2
2
rM N
M Nr
M N
Sd Sd
Rd SdSd Sd
//
///
∑−= Rd.tjeffRd FfAN
cjeffbRd.tRd rfArFM += ∑ .
Sensitivity study, base plate thickness
1015
20
2530
Moment, kNm
Rotation, mrad
t =
0
20
40
60
80
100
120
0 5 10 15 20 25 30
tHE 160 B
MRd
M 20 - 10.9400 kN
∑−= Rd.tjeffRd FfAN
cjeffbRd.tRd rfArFM += ∑ .
Sensitivity study, base plate thickness, resistance
0
2 000
1 000
3 000
100 Moment, kNm
Normal force, kN
Base plate thickness, mm
30
40
25
1520
HE 200 B
MNSd
Sd
30
h = 1 000
M 24
1 600420 590
590
420
1 600
pl.Rd
pl.RdN
Mt,
Column resistance
Simplified prediction
Lever arm is changing by the activation of one bolt rowLever arm is changing by the activation of both bolt rows t
Comparison to experiment
∑−= Rd.tjeffRd FfAN
cjeffbRd.tRd rfArFM += ∑ .
Force, kN
Anchor bolt
E k b
Base plate
Deformation, , mmδConcrete
E k c
E kp
200100
0 0,5
200100
00,5
200100
0 0,5
W7-4.20-propExperiment
Prediction
Moment, kNm
0
20
40
60
80
0 10
t = 20
HE 160 B
h = 500
N M
Rotation, mrad
Force, kN
Force, kN
Components Assembly
Pre-design, stiffness
Lever arm
∑−= Rd.tjeffRd FfAN
cjeffbRd.tRd rfArFM += ∑ .
MSd
z
MSd
z
20tzE
S2
app.ini.j =
Scope of the LectureBasis of designComponents
– Base plate in bending and bolt in tension– Base plate and concrete in compression– Anchor bolt in shear
Assembly– Resistance– Stiffness – Pre-design
Classification Worked examplesSummary
Classification
According to stiffness
Accuracy5% in resistance and 10% in serviceability
Simillar to beam-to-column joints0,6
0,7
0,8
0,9
1
0,0001 0,01 1,00 100,0 S_
S
j,ini,pinS
j,ini,stif
β =FFcr,res
cr.pint = 12 mma1 = b1 = 280 mma = b = 500 mmh = 1000 mmM 24 -420S = 7 100 kNm / radt = 40 mm a1 = b1 = 420 mma = b = 500 mmh = 1000 mmM 24 -420S = 74 800 kNm / ra
log
j,ini,stif
j,ini,pin
Non-Sway by Resistance
Asked stiffness for relative slenderness
oλ ≤ 2 pro oλ ≤ 0,5 Sj,ini ≥ 0pro 0,5 < oλ < 3,93 Sj,ini ≥ 7 (2 oλ - 1) E Ic / Lc
pro oλ ≥ 3,93 Sj,ini ≥ 48 E Ic / Lc
36,1oλ12 E Ic / Lc.Sj,ini ≥
≤
Sway Frames for Serviceability115 kN
5 m
4 m
115 kN
HE 200 B
HE 200 B
5 kN y / yP yS
1,0
0
0,2
0,4
0,6
0,8
0,0001 0,01 1 100 log S
j,ini,pinSSj,ini,stif
In relative values
φ0
0,2
0,4
0,6
0,8
0 0,1 0,2 0,3
1,0
S j.ini.c.s
S j.ini.c.n = 30 E I / Lc c
HingeSemi-rigid connection
Rigidconnection
c c = 12 E I / L
Relative moment
Relative rotation,
36,1o =λ
Scope of the LectureBasis of designComponents
– Base plate in bending and bolt in tension– Base plate and concrete in compression– Anchor bolt in shear
Assembly– Resistance– Stiffness – Pre-design
Classification Worked examplesSummary
Worked Example – Base plate
r = 160
a = 1600
a = 420 a = 590
b = 590t = 30
HE 200 B
1
r
r
b = 420 b = 16001
MFSd Sd
b
30
h = 1000
M 24e = 50
e = 90p = 240
b
a
e = 60c
Contact area
h =200c
c
c c
c
c t =9w
t =15f
b =200c
r b
rc
c
beff
cct =15f
Worked diagram
0
0,2
0,4
0,6
0,8
0 0,1 0,2 0,3
1,0
S j.ini.c.s
S j.ini.c.n = 30 E I / Lc c
c c = 12 E I / L 36,1o <λ(for )
Mj.Rd / M Ny.pl.Rd
cc L/IEφφ =
Worked Example – Frame (sway)
FSd
FSd
FSd
FSd F
Sd FSd F
SdF
Sd
2
FSd
2
24 m
9 m
1,2 m
HE 340 B
IPE 550
HE 340 B
Load combination
w = 2,64 kN/m1
w = 1,65 kN/m2
w1
w2
F FFF2
F F F FF2
yy y y y
yyyy
F = 23,00 kNy
F = 0,38 kNx
F FF2
F F F FF2
xx x x xx
xx
F FFF2
F F F FF2
yy y y y
yyyy
F = 26,79 kNy
First load combination Second load combination
N
N
N
N
φ
H φ
H φ
Frame imperfections – by equivalent forcesElement imperfections – by stability check
Elastic design – connection stiffness, pre-design
z
z
z
rad/kNm1002425,8
20*700*000210k
tzES2
f
2
cb.ini.j ===−
rad/kNm0003436
20*700*000210k
tzES2
f
2
bb.ini.j ===−
rad/kNm4005020
30*400*000210k
tzES2
f
2
cb.ini.j ===
ComparisonMaximalmoment
in base platekNm
momentin corner
kNm
momentin rafterkNm
Verticaldeformation
of raftermm
Horizontalsway
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
00,5
11,5
2
2,53
MaximalMaximal
of corner
Scope of the LectureBasis of designComponents
– Base plate in bending and bolt in tension– Base plate and concrete in compression– Anchor bolt in shear
Assembly– Resistance– Stiffness – Pre-design
Classification Worked examplesSummary
SummaryComponent methodGood accuracy
Worked examples– Savings by taking into account of
stiffness (for serviceability only)– Hand calculation unusual
1
Fire Design of Connections
Lessons Connection Design according to EN 1993-1-8
Prof. František Wald
2
List of Lessons at Seminar1. Introduction2. Bases of design according to EN 1993-1-83. Welded connections4. Bolted connections5. Basics of structural joints6. Design of simple connections 7. Column bases8. Fire design of connections, EN 1993-1-29. Seismic design, EN 1998-1-1
3
Scope of the LectureStructural fire designTemperature of connectionsConnectors at elevated temperatureComponent methodStructural integritySummary
4
Structural Fire Design – Procedure of DesignThermal analysesof 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)
5
Connections under FireSteel looses with temperature strength and stiffness
Steel structures expand when heated and contract on cooling
Temperature within the connections is lower compare to connecting steel members
6
EN 1993-1-2 Approaches Fire protection is applied to the member and its connections
Rules based to protect as members
Component approach in EN 1993-1-8 together with a method for calculation the behaviour of welds and bolts at elevated temperature
Connection moment, shear and axial capacity can be evaluated at elevated temperature
7
Scope of the LectureStructural fire designTemperature of connectionsConnectors at elevated temperatureComponent methodStructural integritySummary
8
Analytical Models of Heat Transfer1. Section factor (Am /V) method simmilar as for members
Am /V surface/volume ratio2. Based on the temperature of the beam lower flange
Concrete slab
h
400 mm0,62
0,88
> 400 mm0,70
0,88
0,88
hh
θ0
θ0
θ0
h h
θ0
0
≤
0,75 0θ
θ
9
Accuracy Demonstration on 7th Large Scale Fire Experiments on Steel Frame
9000 9000 9000 9000 9000
9000
6000
6000
E
1
2
3
4
F D C B A
Fire Compartment for Structural Integrity Fire Test, January 16, 2003 10
Fire Test January 16. 2003
Motivation
Temperatures in elements and connectionsInternal forces in the connectionsBehaviour of the composite slab
11
Fire Compartment
Interier Exterier, Fire load 12
148 thermocouples57 low temperature strain gauges10 high temperature strain gauges37 deformations10 video cameras2 thermo-imaging cameras
Instrumentation
13
Moderate Fire
Maximal temperature 1108 °C in 55 min 14
No Collapse Reached
Deflections over 1000 mm; residual deflections 925 mm
15
Fin Plate Connection before the Experiment
Fire compartment N
E2D2
E1D1
Fin plate connection
16
C454 - 462
D E
Thermocouples at elements and connections, numbered Cijk
N
C486 - 488 C472 - 475
C441 - 449 C483 - 485 C450 - 453
C480 - 482
C463 - 471 C475 - 479
Thermocouples in compartment 300 mm below ceiling, numbered Gijk
G525
G526
G527
G528
G529
G530
G531
G532
G533
G534
G535
G536
2G521
G522
G523
G5241
C441C442C443
C446
West view
120D1/2-E1/2
C444
C445
C447
C448
C449
C450C451C452
West view
120
C453
E1/2-D1/2
DE1/2
North view
C483C484
C485
FIRE COMPARTMENT
Walls
Window
1st bolt row
4th bolt row3rd bolt row2nd bolt row
Instrumentation
17
400,0°C
980,0°C
400
600
800
t = 26 min. θcon,ø = 275 °C
In 26 min of fire is temperatureof the structure under 400°C
600
1000 , °Cθ
00 30 60 90 mint,
Gas temperatureHeating
Time
18
400,0°C
980,0°C
400
600
800
t = t0 + 0 h 28’ Tcon,ø = 330 °C
600
1000 , °Cθ
00 30 60 90 mint,
Time
HeatingGas temperature
t = 28’ θcon,ø = 330 °Ct = 26 min θcon,ø = 275 °C
25
400,0°C
980,0°C
400
600
800
t = t0 + 0 h 42’ Tcon,ø = 645 °C
600
1000 , °Cθ
00 30 60 90 mint,
t = 42 min θcon,ø = 645 °C
Buckling of beam lower flange
26
400,0°C
980,0°C
400
600
800
t = t0 + 0 h 44’ Tcon,ø = 660 °C
600
1000 , °Cθ
00 30 60 90 mint,
t = 44 min θcon,ø = 660 °C
Buckling of beam lower flange
27
400,0°C
980,0°C
400
600
800
t = t0 + 0 h 46’ Tcon,ø = 685 °C
600
1000 , °Cθ
00 30 60 90 mint,
t = 46 min θcon,ø = 685 °C
28
400,0°C
980,0°C
400
600
800
t = t0 + 0 h 48’ Tcon,ø = 710 °C
600
1000 , °Cθ
00 30 60 90 mint,
t = 48 min θcon,ø = 710 °C
29
400,0°C
980,0°C
400
600
800
t = t0 + 0 h 50’ Tcon,ø = 730 °C
600
1000 , °Cθ
00 30 60 90 mint,
t = 50 min θcon,ø = 730 °C
30
400,0°C
980,0°C
400
600
800
t = t0 + 0 h 52’ Tcon,ø = 775 °C
600
1000 , °Cθ
00 30 60 90 mint,
t = 52 min θcon,ø = 775 °C
31
400,0°C
980,0°C
400
600
800
t = t0 + 0 h 54’ Tcon,ø = 810 °C
600
1000 , °Cθ
00 30 60 90 mint,
Gas temperatureCooling
Time
t = 54 min θcon,ø = 810 °C
32
400,0°C
980,0°C
400
600
800
t = t0 + 0 h 56’ Tcon,ø = 835 °C
The maximal temperature of 1088 °C of secondary beam was reachedby its lower flange in 57 min
600
1000 , °Cθ
00 30 60 90 mint,
Gas temperatureCooling
Time
t = 56 min θcon,ø = 835 °C
33
400,0°C
980,0°C
400
600
800
t = t0 + 0 h 58’ Tcon,ø = 855 °C
600
1000 , °Cθ
00 30 60 90 mint,
Gas temperatureCooling
Time
t = 58 min θcon,ø = 855 °C
34
400,0°C
980,0°C
400
600
800
t = t0 + 1 h 00’ Tcon,ø = 880 °C
600
1000 , °Cθ
00 30 60 90 mint,
Gas temperatureCooling
Time
t = 60 min θcon,ø = 880 °C
35
400,0°C
980,0°C
400
600
800
t = t0 + 1 h 02’ Tcon,ø = 900 °C
Maximal temperatureof fin plate connection 908,3°C was reached in 63 min
600
1000 , °Cθ
00 30 60 90 mint,
t = 62 min θcon,ø = 900 °C
36
400,0°C
980,0°C
400
600
800
t = t0 + 1 h 04’ Tcon,ø = 885 °C
600
1000 , °Cθ
00 30 60 90 mint,
t = 64 min θcon,ø = 885 °C
43
400,0°C
980,0°C
400
600
800
t = t0 + 1 h 18’ Tcon,ø = 755 °C
600
1000 , °Cθ
00 30 60 90 mint,
t = 78 min θcon,ø = 775 °C
44
400,0°C
980,0°C
400
600
800
t = t0 + 1 h 20’ Tcon,ø = 745 °C
600
1000 , °Cθ
00 30 60 90 mint,
t = 80 min θcon,ø = 745 °C
45
400,0°C
980,0°C
400
600
800
t = t0 + 1 h 22’ Tcon,ø = 740 °C
600
1000 , °Cθ
00 30 60 90 mint,
t = 82 min θcon,ø = 740 °C
46
400,0°C
980,0°C
400
600
800
t = t0 + 1 h 24’ Tcon,ø = 730 °C
600
1000 , °Cθ
00 30 60 90 mint,
t = 84 min θcon,ø = 730 °C
47
400,0°C
980,0°C
400
600
800
t = t0 + 1 h 26’ Tcon,ø = 720 °C
600
1000 , °Cθ
00 30 60 90 mint,
t = 76 min θcon,ø = 720 °C
48
400,0°C
980,0°C
400
600
800
t = t0 + 1 h 28’ Tcon,ø = 710 °C
600
1000 , °Cθ
00 30 60 90 mint,
t = 78 min θcon,ø = 710 °C
67
Fin plate connection after the fire test
68
Temperature Differences Measured by Thermocouples
Maximal temperature of fin plate by 4th bolt 908 °C in 63 min
E2D2
E1D1
0
200
400
600
800
1000
0 15 30 45 60 75 90 105 120 135 Time, min
Fin plate, by 4th bolt
Measured temperature, °C
Beam, bottom flange
Difference shown
imaging by the thermo
camera
69Measured 908 °C in 63 min.; predicted 878 °C in 53 min
Analytical Prediction Compared to Test
E2D2
E1D1
0
200
400
600
800
1000
0 15 30 45 60 75 90 105 120 135 Time, min
Measured
from gas measured temp.Connection temperature, °C
based on "section factor"
Predicted
based on measured temp.from beam bottom flange
Predicted
70
Scope of the LectureStructural fire designTemperature of connectionsConnectors at elevated temperatureComponent methodStructural integritySummary
71
Bolts and Welds Properties at Elevated TemperatureFactors kb,θ; kw,θ are used to describe the strength reduction
00,10,20,30,40,50,60,70,80,9
1
0 200 400 600 800 1000 θ a ,°C
ky,θ
kb,θ
kw,θ
Carbon steel
Bolt
Weld
72
Bolt Resistance at Elevated TemperatureMarked loss of strength between 300 and 700ºCShear resistance of bolts in fire
Bearing resistance of bolts in fire
Tension resistance of a bolts in fire
γΜ partial safety factor for the resistanceγΜ,fi partial safety factor for fire
fi,m
m,bRd,vRd,t,v kFFγγ
θ=
fi,m
m,bRd,bRd,t,b kFFγγ
θ=
fi,m
m,bRd,tRd,t,ten kFFγγ
θ=
73
Filled Weld Resistance at Elevated TemperatureDesign strength per unit length of a fillet weld in a fire
γΜ partial safety factor for the resistanceγΜ,fi partial safety factor for fire
fi,m
m,wRd,wRd,t,w kFFγγ
θ=
74
Butt Weld Resistance at Elevated TemperatureFor full penetration butt weld up to 700ºCas equal to the strength of the weaker part of the joint using the appropriate reduction factors for steel
For temperatures higher than 700ºCthe reduction factors for fillet welds to butt welds
75
Scope of the LectureStructural fire designTemperature of connectionsConnectors at elevated temperatureComponent methodStructural integritySummary
76
Component MethodDecomposition of jointComponnet descriptionJoint assembly
φM
z
77
Component MethodDecomposition of jointComponet descriptionJoint assembly
Component
Cº20;i,y;i FkF θ = ;
Cº20;i,E;i KkK θθ = ;
Cº20;i
;E
;y
;i
;i;i k
kKF
δθ
θ
θ
θ ==
Joint
Cº20;i;y;i MkM θθ = ;
Cº20;i;E
;y
;i
;i;i k
kSM
φφθ
θ
θ
θθ == ;
Cº20;i;E
i ;i
2
;i Sk
k1zES θ
θ ==∑
;
Force
Stiffness
Deformation
Moment
Rotation
Stiffness
θ
θ
θ
θ
δ
78
φ , mrad
M, kNm
20 ºC
800ºC
500ºC100ºC
50
0200 10040 60 80
600ºC700ºC
φM
z
Moment
Rotation
Component MethodDecomposition of jointComponnet descriptionJoint assembly
79
Worked ExampleFire resistance of an end plate connection of the truss lower flangeRequired R30
4 x M24
P 28
85 125 40 45
150500 kN 500 kN
80
Fire ResistanceUnprotectedSection factorFire resistance(exposed to nominal standard fire curve)
ProtectedIntumescent paintFire resistance(exposed to nominal standard fire curve)
4 x M24
P 28
85 125 40 45
150500 kN 500 kN
1m m18,4324,1/0,54V/A -==
t = 44 min
dp = 15 mm
13
p
pm KWm288015,0
1,018,43dV
A --==λ
= 112 mint
81
Scope of the LectureStructural fire designTemperature of connectionsConnectors at elevated temperatureComponent methodStructural integritySummary
82
Structural IntegrityIf used catenary actions of beams and slabs
In case of advanced design models
Resistance of connections to horizontal forces at ultimate limit state(for fu)
83
FE Simulation of Cardington Test
Heating Cooling 720°C
I. Beam onlyII. One sectionIII. Full floor
Normal force, kN
Time, min
Model of structure
60 80
300
200
100
0
-100
-200
- 300
20 100
40
4 x 6,0 m
Observed joint 6 x 3,75 m
I. II. III.
84
Experiment in Cardington
853rd floor
99 97 107 105103 101 111 109
83 81 91 89
87 85 95 93
115 113119 117
127 125
123 121
500
500
500
500
113,117115, 119
99, 103 97, 101
83,87 81, 85
127, 123 121, 125
107, 111 105, 109
91, 95 89, 93
4th floor
5th floor
N
of the fire compartment
PLAN Internal wall
7,0 m
11,0 m
E1D1
D1 E1
y
z
309,2
13,821,7
15,2
UC 305 x 305 x 137
320,5
20 20
2020
(339,9)
(314,5)
(19,1)(31,4)
(UC 305 x 305 x 198)
UC 305 x 305 x 137UC 305 x 305 x 198
Window 1,27 x 8,70 m
Low Temperature Strain Gauges
At externalcolumns
86
Protected Columns
Internal External (with 1 m of beam)
87
Measured Stresses at External Columns
Section 500 mm above the floor at 4th floor
83 81 91 89
87 85 95 93
Column D1 Column E1
4th floor
-200
-150
-100
-50
0
50
100
150
15 30 45 60 75 90 105 120 135 150 165 180 195 210
Time, min.
Stress, MPa
8183
87
8991
93
95
D1, E1
500 mm
88
Measured Bending Moments in Columns
Time, min.
Bending moments, kNm
-200
0
200
400
600
0 60 120
a-D1
b-D1c-D1
c-E1
d-E1d-D1
4th floor
D1D2
5th floor
3rd floor
2nd floor
a-D1
b-D1c-D1; c-E1d-D1; d-E1
89
Measured Forces in External Columns
Forces at 3rd, 4th and 5th floor calculated from strainganges at level c,d
(5th foor)3rd floor
4th floor
-500
-400
-300
-200
-100
0
100
200
300
0 60 120
Everage
Everage
d-D1d-E1
c-E1
c-E1
c-D1
c-D1
d-D1 d-E1
Time, min.
4th floor
D1D2
5th floor
3rd floor
2nd floor
Ft,5
Ft,4
Ft,5
Ft,4
Ft,3 Ft,3
a-D1
b-D1c-D1; c-E1d-D1; d-E1
Force, kN
Beam model
90
Required Tie Forces - ReferencesBS 5950: Structural use of steelwork in buildingsEN 1991-1-7 Actions – Exceptional loading
Column ties
Edge ties Beams not used as ties
Tie anchoring
Tie anchoring free column A
re-entrant corner
A
91
Column ties
Edge ties Beams not used as ties
Tie anchoring
Tie anchoring free column A
re-entrant corner
A
Required Tie Forces
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
[ ]75614150min ;Ls)q,g,(,F tkkt +=
92
Scope of the LectureStructural fire designTemperature of connectionsConnectors at elevated temperatureComponent methodStructural integritySummary
93
SummaryWell designed connections at ambient temperature do not need to be recalculated at elevated temperature, if are not directly exposed to fireThe structural fire design according to EN 1993-1-2 is ready for design of connections exposed to fire
Thermal analyses Transfer of heat
EN 1991-1-2
Mechanical behaviour into structureof fire compartment at elevated temperature
EN 199x-1-2
or local fire
94
List of Lessons at Seminar1. Introduction2. Bases of design according to EN 1993-1-83. Welded connections4. Bolted connections5. Basics of structural joints6. Design of simple connections 7. Column bases8. Fire design of connections, EN 1993-1-29. Seismic design, EN 1998-1-1
95
Thank you for your attention
1
Seismic Design of Connections
Lessons Connection Design according to EN 1993-1-8
Prof. František Wald
2
List of Lessons at Seminar1. Introduction2. Bases of design according to EN 1993-1-83. Welded connections4. Bolted connections5. Basics of structural joints6. Design of simple connections 7. Column bases8. Fire design of connections, EN 1993-1-29. Seismic design, EN 1998-1-1
3
Scope of the LecturePrinciplesDesign criteria
Beam-to-column typologiesDesign and fabrication recommendationsWelding technology
Strain-rate loadingM - φ modellingColumn web panelSummary
4
PrinciplesBasic conditions
Over-strength demandDuctility demand (rotation capacity)Robustness demand (reliable detailing together with material behaviour)
Northridge and Kobe earthquakeUnexpected damages to connections
Detailing practicesWelding
5
Scope of the LecturePrinciplesDesign criteria
Beam-to-column typologiesDesign and fabrication recommendationsWelding technology
Strain-rate loadingM - φ modellingColumn web panelSummary
6
Design Criteria for Seismic Resistant FramesStrong Column/Weak Beam design principlePanel zone strengthConnection strength and degradation characteristicsP-δ effectsMember local buckling
7
Design Criteria in USAGuidelines designs for frames with different anticipated seismic demands
1997 NEHRP ProvisionsAISC Seismic Provisions
Ordinary Moment Resisting Frames (OMRF) Plastic rotation capacities of 0,01 rad
Intermediate Moment Resisting Frames (IMRF)Plastic rotation capacities of 0,02 rad
Special Moment Resisting Frames (SMRF)Plastic rotation capacities of 0,03 rad
8
Requirements for ConnectionSuccessful Performance
Welded JointsThrough-Thickness StrengthBase Material Notch-ToughnessWeld Wire Notch-ToughnessWeld backing and Run out TabsReinforcing Fillet WeldsCope Hole Size, Shape, Workmanship
Bolted JointsBolt Sizing, Hole Type, TighteningNet Section Strength
9
Design Criteria in EuropeEN 1998-1-1 basic provisions concerning steel joints
General rules for steel connections in dissipative structuresRequirements for MRF (Moment Resistant Frame) beam-to-column connections
EN 1993-1-8Rotational stiffness of a joint Sj
axial force NSd in the connected member not exceed 10%Rotation capacity
10
Scope of the LecturePrinciplesDesign criteria
Beam-to-column typologiesDesign and fabrication recommendationsWelding technology
Strain-rate loadingM - φ modellingColumn web panelSummary
11
Beam-to-Column TypologiesFEMA/SAC test programmes
Connection type classified for certain ranges of Member sizePlastic rotation angle
Connection typesWelded 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) 12
Connection TypesPrescriptive Moment Frame Connection
13
Welded Flange Plate Connection
14
Welded Column Tree with Bolted Beam
15
Field Bolted Types of ConnectionsGuidelines 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)
16
Field Bolted Types of ConnectionsBolted end plate (BEP)
17
Field Bolted Types of ConnectionsWelded flange plates with bolted beam (WFPBB)
18
Field Bolted Types of ConnectionsBolted double haunch (BDH)
19
Beam-to-Column TypologiesSpecific joints in Japan
Stiffener Stiffener
20
Beam-to-Column TypologiesSpecific joints in Europe
Extended end plate joint
.
.
10M20 - 10.9
.
A
A-A
A
21
Beam-to-Column TypologiesSpecific joints in Europe
Welded joint
.
.
.
B-B
BB
22
Beam-to-Column TypologiesSpecific joints in Europe
Welded flange plate joint
3M20 - 6.6
.
.
.
C-C
CC
23
Scope of the LecturePrinciplesDesign criteria
Beam-to-column typologiesDesign and fabrication recommendationsWelding technology
Strain-rate loadingM - φ modellingColumn web panelSummary
24
General Rulesfor Steel Connections in Dissipative Structures
Localisation of plastic strains, high residual stresses,and fabrication defects
By experimental evidence
Non dissipative connections of dissipative members Full penetration butt welds
Deemed to satisfy the overstrength criterion
For fillet weld or bolted non dissipative connections
fyd R35,1R ≥
25
General Rulesfor Steel Connections in Dissipative Structures
Bolted jointsIn shear categories B and C (slip resistant) onlyUn tension category E With controlled tightening of the bolts
Shear joints with fitted bolts are also allowed.
Bolted shear connectionThe shear resistance of the bolts should be higher than 1,2 timesthe bearing resistance
The strength and ductility of members and their connections under cyclic loading
Should be supported by experimental evidenceFor all types of connections in dissipative zonesAvailable plastic rotation )L5,0/(p δφ =
26
Requirements for Moment Resistant Frame beam-to-column connections
Structure dissipate energy in the beamsConnections between the beams and the columns should be designed for the required degree of overstrengthMoment resistance Mpl.Rd and the shear force (VG, Ed + VM,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
Connections have a rotation capacity consistent with global deformationsMembers 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
27
Requirements for Moment Resistant Frame Beam-to-Column Connections
Connection design Plastic rotation capacity φCd in the plastic hingeNot less than 35 mrad for structures of ductility class H and 25 mrad for structures of ductility class M with q>2. Under cyclic loading without degradation of strength and stiffness greater than 20%Supported by experimental evidence
Partial strength connections Column capacity design from the plastic capacity of connections
28
Design and Fabrication RecommendationsMaterial propertiesYield-to-Ultimate Stress Ratio (YUSR)
YUSR (fy/fu) = 0,65 or 0,80 For a plastic rotation capacity up to 0,030 rad.
YUSR = 0,95 Reduced plastic hinge length at a plastic rotation capacity of 0,030 rad
The plastified length of the beam with YUSR = 0,95Half the corresponding length in YUSR = 0,80
29
Scope of the LecturePrinciplesDesign criteria
Beam-to-column typologiesDesign and fabrication recommendationsWelding technology
Strain-rate loadingM - φ modellingColumn web panelSummary
30
Design and Fabrication RecommendationsAccess Hole Size and Geometry
31
Design and Fabrication RecommendationsAccess Hole Size and GeometryIncreasing the size of the web cope
Easier welding on the beam bottom flangeBetter weld quality
Standard ModifiedConfigurations of weld access hole
20
25 10
25
38
2510
25 50
20
32
Scope of the LecturePrinciplesDesign criteria
Beam-to-column typologiesDesign and fabrication recommendationsWelding technology
Strain-rate loadingM - φ modellingColumn web panelSummary
33
Strain-Rate LoadingThe strain-rate loading has an important influence on the behaviour of jointsA strain rate typical for steel members yielding under seismic action in the range of 0,03-0,06 s-1
Increases the yield strengthLower ultimate strength of welded connectionsDuctility is reduced by up to 27%Decrease of ductility due to high strain rates is not straightforward for cyclic loading
34
Strain-Rate of Carbon Steel
Stress
Strain
Very high speedE Conventional speed
35
Strain-Rate of Carbon Steel
ydyn,yfy,DIF f/f=α
udyn.ufu,DIF f/f=α
Time to yield stress αDIF.fy α DIF.fu
> 1 s 1,0 1,00 100 ms 1,1 1,05 10 ms 1,6 1,05 1 ms 1,9 1,05
36
Strain-Rate of Austenitic Steel
EN 10088-2 1.4307 (304L) increase of f02 o cca 7% - 28%
Stress, MPa800
600
400
200
0
15 30
Strain, % 45 75 60
-1-4
50 s140 s
10 s-1-210 s
-1502 s
-1
-1
37
Scope of the LecturePrinciplesDesign criteria
Beam-to-column typologiesDesign and fabrication recommendationsWelding technology
Strain-rate loadingM - φ modellingColumn web panelSummary
38
M - φ ModellingStable behaviourUnstable curveSlip in connection
M
φ
M
φ
M
φ
39
M - φ ModellingStable behaviourUnstable curveSlip in connection
40
ParametresRotational capacity
Energy
Rotational capacity and energy
Stiffness
Resistance ini.j
i.ji.M M
M=β
ini.j
i.ji.S S
S=β
( )elixel.jel
iii.E M
Eφφφ
φβ−
=
el.j
i.ji. φ
φβ =Δ
( )eliel.j
ie M
Eφφ
β−
=
41
ModelsCurve fitting
Initial stiffnessMoment resistanceUnloading
ComponentComponent cycling descriptionAssembling
42
Exponential CurveInitial stiffness Sj,ini
Moment resistance M0
Unloading Sj,s
M
φ
SS
S
S
j.ini
j.ini
j.s
j.s
M
φa
0
Ma
- M0
( )( )
( )( )( )φφ
φφ
φφφ −−
⎥⎥⎦
⎤
⎢⎢⎣
⎡ −−+
−−−== − as.jn/1
0
nas.jini.j
as.jini.j1iii.jj S
M2SS
1
SSMSM
43
Scope of the LecturePrinciplesDesign criteria
Beam-to-column typologiesDesign and fabrication recommendationsWelding technology
Strain-rate loadingM - φ modellingColumn web panelSummary
44
Column Web PanelT joints or double T joints with unsymmetrical loads strong influence on the behaviour of the jointThe resistance of the joint is reduced by between 20 - 40% and the ductility is increased by 150 - 200%, due to the web panel. Adding supplementary web plates on the column web panelcan increase the resistance of the joint.
45
Column Web Panel
For static loads For seismic loads
beff
Ls
beff
r
46
High Strength Bolts in Seismic JointsHigh strength bolts (in US HSFG, High Strength Friction Grip bolts) can be used as ordinary bolts in seismic jointsIt is recommended that they are tightened at a level of 50% of their preloading force. In this case the surfaces of the plates do not have to be prepared for working as a slip-resistant connection
47
Scope of the LecturePrinciplesDesign criteria
Beam-to-column typologiesDesign and fabrication recommendationsWelding technology
Strain-rate loadingM - φ modellingColumn web panelSummary
48
List of Lessons at Seminar1. Introduction2. Bases of design according to EN 1993-1-83. Welded connections4. Bolted connections5. Basics of structural joints6. Design of simple connections 7. Column bases8. Fire design of connections, EN 1993-1-29. Seismic design, EN 1998-1-1
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