a prototype of knowledge based expert system for design of structural steel joints
Design of Structural Steel Joints
Transcript of Design of Structural Steel Joints
Design of Structural Steel Joints
Dr. Klaus WeynandFeldmann + Weynand GmbH, Aachen, Germany
Prof. Jean-Pierre JaspartUniversity of Liège, Belgium
Design of Structural Steel Joints
• Introduction
• Integration of joints into structural design process
• Moment resistant joints
• Simple joints
• Design tools
Design of Structural Steel Joints
• Introduction• Integration of joints into
structural design process
• Moment resistant joints
• Simple joints
• Design tools
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
EN 1993 Part 1.8
Chapter 1 – Introduction
Chapter 2 – Basis of design
Chapter 3 – Connections made with bolts, rivets or pins
Chapter 4 – Welded connections
Chapter 5 – Analysis, classification and modelling
Chapter 6 – Structural joints connecting H or I sections
Chapter 7 – Hollow section joints
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Design of simple joints
ECCS Publication No 126 (EN)
• Background information
• Design guidelines
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
2 – Basis of design Partial safety coefficients
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
3 – Connections made mechanical fasteners
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
4 – Welded connections
Design of Structural Steel Joints
• Introduction
• Integration of joints into structural design process
• Moment resistant joints
• Simple joints
• Design tools
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Actual joint response
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Actual joint response
M
M Rd
S j,inicd
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Influence on the structural response
• Displacements
• Internal forces
• Failure mode and failure load
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
M
M
?
?
?
M
Characterization
Modelling
Classification
Idealization
Four successive steps for structural integration
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Characterization
Search for a unified approach whatever the material
M
?
?
?
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Various configurations (1)Continuity
Beam-to-beam
Column bases
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Various configurations (2)Joints in portal frames
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Various configurations (3)
Connections and joints incomposite construction
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Various cross-section shapes (1)
Hot-rolled and
cold-formed
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Various cross-section shapes (2)
Built-up profiles
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Various connection elements
Splices
Cleats
End plates
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Economy
Reduced fabrication, transportation and erection costs
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Specific design criteria
Robustness
Joints as key elements
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Characterization (1)
Search for a unified approach
M
?
?
?
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Characterization (2)
Eurocode 3 – Part 1-8
• Beam-to-beam joints, splices, beam-to-column joints and column
bases:
welded connections
bolted connections (anchors for column bases)
Background: COMPONENT METHOD
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Three steps
First step
Identification of the
active components
Second step:
Response of the
components
Third step:
“Assembly” of the
components
F F F
E k1 E k2E k3
F1,RdF2,Rd
F3,Rd
column webin shear
column webin tension
column webin compression
M
Sj,ini
Mj,Rd
cd
, ,minj Rd i RdM F z
2
, 1j ini
i
E zS
k
Characterization (3) - component method
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Characterization (4) - component method
EC3 Part 1-8 provides therefore:
• a library of components
• rules for the evaluation of the properties of the components
(stiffness, resistance, deformation capacity)
• rules for the evaluation of the possible component interactions
• « assembly » rules for components
Applicable for simple joint and moment resistant joint
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Characterization (4) – Hollow section jointsDifferent approach for lattice girder joints
For many types of joint configurations:
• Joints considered as a whole
• Check of relevant failure modes
• Scope of application to be checked
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
M
M
?
?
?
M
Characterization
Modelling
Classification
Idealization
Four successive steps for structural integration
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Classification (1)
Stiffness
Sj,ini
Pinned
Semi-rigid
RigidM j
Boundaries for stiffness
Joint initial stiffness
Semi-rigid
Rigid
Pinned
Classification boundariesInitial joint stiffness
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Classification (2)
Resistance
Mj,Rd
Partial-strength
Full-strength
Pinned
Mj
Boundaries for strength
Joint strength
Full resistance
Partial resistance
Pinned
Classification boundariesJoint resistance
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Classification (3)
Ductility
• Brittle
• “Semi-ductile”
• Ductile
Mj
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
M
M
?
?
?
M
Characterization
Modelling
Classification
Idealization
Four successive steps for structural integration
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Modelling
JOINT
MODELLING
BEAM-TO-COLUMN JOINTS
MAJOR AXIS BENDING
BEAM
SPLICES
COLUMN
BASES
SIMPLE
SEMI-
CONTINUOUS
CONTINUOUS
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
M
M
?
?
?
M
Characterization
Modelling
Classification
Idealization
Four successive steps for structural integration
Design of Structural Steel Joints
• Introduction
• Integration of joints into structural design process
• Moment resistant joints• Simple joints
• Design tools
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
ExampleSingle sided beam-to-column joint configuration, bolted end-plate connection
+ +
+ +
M
V
15
3
IPE220
HEB140
120
60 10
8030 30
240
4 M16 8.8
140
u=10p=60
5
w=
To be evaluated:
Design moment resistance , initial stiffness
0
1
1,01,0
M
M
Material: S 235
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
General data
2 2 140 2 12 2 12 92wc c fc ch h t r mm
2
2 2
4295,6 2 140 12 7 2 12 12 1307,6vc c c fc wc cA A b t t r
mm
80 70,8 0,8 12 26,9
2 2
fc
c
w tm r mm
140 8030
2 2
cb we mm
2 2
,
0
12 2350,25 0,25 8460 /
1,0
fc yc
pl fc
M
t fm Nmm mm
Column
Equivalent T-stub in tension
F /4t
Ft
F /4t
F /4t
F /4t
m e
leff
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
General data
+ +
+ +
15
3
IPE220120
60 10
8030 30
240
4 M16 8.8
140
u=10p=60
5
w=
z
9,2220 10 60 165,4
2 2
fb
b
tz h u p mm
6,
,
0
285.406 235 10 (classe 1 section) 67,07
1,0
pl yb yb
c Rd
M
W fM kNm
Lever arm
Beam
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
General data
2 2
,
0
15 2350,25 0,25 13.218 /
1,0
p yp
pl p
M
t fm Nmm mm
mp
mp2
80 5,90,8 2 0,8 2 3 33,66
2 2
wbp w
w tm a mm
2 0,8 2 60 10 9,2 0,8 2 5 35,14p fb fm p u t a mm
140 8030
2 2
p
p
b we mm
End plate
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
General data
5,5
1
33,660,53
33,66 30
p
p p
m
m e
2
2
35,140,55
33,66 30
p
p p
m
m e
Alpha factor for effective lengths
End plate
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
General data
3
,
0,9 0,9 800 157 1090,43
1,25
ub st Rd
Mb
f AF kN
3
,
0,6 0,6 800 157 10 (shear plane in thread) 60,3
1.25
ub sv Rd
Mb
f AF kN
1
0,5 12 15 10 14,8 2 4 47,42
b fc p bolt nutL t t h h mm
Bolts
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Component No 1 – Column web in shear
Vwp
Vwp
F
M
z
F
3,
,
0
0,9 0,9 1307,6 235 10159,7
3 3 1,0
vc y cw
wc Rd
M
A fV kN
Assumption : 1
,
,1
159,7159,7
1
wc Rd
Rd
VF kN
1
0,38 0,38 1307,63,004
1 165,4
vcAk mm
h
Resistance
Stiffness coefficient
Transformation parameter
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Component No 2 – Column web in compression
, , min 2 2 2 5 ; 2 5
min 9,2 2 5 2 2 15 5 12 12 ; 9,2 5 2 15 10 5 12 12 161,27
eff c wc fb f p fc fb f p fcb t a t t s t a t u t s
mm
, ,Assumption : min 1,0; 1,7 / 1,0wc com Ed y wck f
, , ,
2
161,27 92 2350,932 0,932 0,543 0,673 1,0
210000 7 7
eff c wc c y wc
p
wc
b d f
E t
1 2 2
, ,
1 10,713
1 1,3 161,27 7 1307,61 1,3 /eff c wc wc vcb t A
3
,2 , , , 1/ 1 0,713 1 161,27 7 235 10 1,0 189,1Rd wc eff c wc wc y wc MF k b t f kN
Resistance
Reduction factors to account for compression stresses and instability
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Component No 2 – Column web in compression
F
F k Ei i i
, ,
2
0,7 0,7 161,27 78,589
92
eff c wc wc
wc
b tk mm
h
Stiffness coefficient
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Component No 3 – Column web in tension
, , min 2 ;4 1,25 min 2 26,9;4 26,9 1,25 30 145,10eff t wcb m m e mm
1 2 2
, ,
1 10,749
1 1,3 145,1 7 1307,61 1,3 /eff t wc wc vcb t A
3
,3 , , , 0/ 0,749 145,1 7 235 10 1,0 178,7Rd eff t wc wc y wc MF b t f kN
, ,
3
0,7 0,7 145,1 77,728
92
eff t wc wc
wc
b tk mm
h
Resistance
Stiffness coefficient
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Equivalent T-stub in tension
Component No 4 – Column flange in bendingComponent No 5 – End plate in bending
F /4t
Ft
F /4t
F /4t
F /4t
m e
leff
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
T-stub – Effective length
Distinction between circular and non-circular yield line patterns
Circular patterns Non-circular patterns
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
T-stub – Effective length
Groups effects to consider in addition to the individual response of each bolt-row
Group 1+2 Group 2+3 Group 1+2+3
Row 1
Row 2
Row 3
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
T-stub – Effective length
Groups effects to consider in addition to the individual response of each bolt-row
Row 3
,3 ,3, ,3, ;( )Rd Rd indiv Rd groupF min F F
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Bolt rows consideredIn this example: only bolt row 1 is considered for tension forces
+ +
+ +
M
V
15
3
IPE220
HEB140
120
60 10
8030 30
240
4 M16 8.8
140
u=10p=60
5
w=
Row 1
Row 2
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Component No 4 – Column flange in bending
, , , , 145,1 (see column web in tension)eff t fc eff t wcl b mm
min ;1,25 ; / 2 min 30;1,25 26,9;30 30pn e m b w mm
Resistance
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
3, , , , 3
, , 2
2 2 2 145,1 8460 2 90,4 10 3010 138,5
26,9 30
eff t fc pl fc t Rd
fc Rd t
l m B nF kN
m n
, , 3 ,2 2 90,43 180,9fc Rd t t RdF B kN
Mode 1 - Complete yielding of the flange
Mode 2 - Bolt failure with yielding of the flange
Mode 3 - Bolt failure
Component No 4 – Column flange in bending
, , , 3
, , 1
4 4 145,1 846010 182,5
26,9
eff t fc pl fc
fc Rd t
l mF kN
m
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Component No 4 – Column flange in bending
,4 , , 1 , , 2 , , 3min ; ; 138,5Rd fc Rd t fc Rd t fc Rd tF F F F kN
3 3, ,
4 3 3
0,9 0,9 145,1 1211,59
26,9
eff fc t fcl tk mm
m
Resistance
Stiffness coefficient
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Component No 5 – End plate in bending
, , min 2 ; min 2 33,66; 5,5 33,66 185eff t p p pl m m mm
min ;1,25 ; min 30;1,25 33,66;30 30p p pn e m e mm
, , , 3
, ,1
4 4 185 13.218Mode 1: 10 291
33,66
eff t p pl p
ep Rd
p
l mF kN
m
3, , , , 3
, ,2
2 2 2 185 13.218 2 90,43 10 30Mode 2: 10 162,1
33,66 30
eff p t pl p t Rd p
ep Rd
p p
l m B nF kN
m n
,5 , ,1 , ,2 , ,3min ; ; 162,1Rd ep Rd ep Rd ep RdF F F F kN
Resistance
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Component No 5 – End plate in bending
3 3, ,
5 3 3
0,9 0,9 185,0 1514,73
33,66
eff t p p
p
l tk mm
m
Stiffness coefficient
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Component No 7 – Beam flange and web in compression
,7 , 3
67,07/ 318,2
210,8 10Rd c Rd b fbF M h t kN
7k
Resistance
Stiffness coefficient
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Component No 8 – Beam web in tension
, , , , 185eff t wb eff t pb l mm
3
,8 , , 0/ 185 5,9 235 10 1,0 256,5Rd eff t wb wb yb MF b t f kN
8k
Resistance
Stiffness coefficient
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Component No 10 – Bolts in tension
,10 ,2 2 90,43 180,9Rd t RdF B kN
10
1571,6 1,6 5,30
47,4
s
b
Ak mm
L
Mode 3 in T-stubs for components:
• “column flange in bending”
• “end plate in bending”
Resistance
Stiffness coefficient
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Mj,Rd
Design moment resistance
,min 138,5 (Column flange in bending)Rd Rd iF F kN
3
, 138,5 165,4 10 22,91j Rd RdM F z kNm
, , ,
215,27
3j el Rd j RdM M kNm
Design plastic moment resistance
Relevant component
Design elastic moment resistance
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Stiffness
Sj,ini
2 62
,
210000 165,4 10/ 1 6234 /
1 1 1 1 1 1
3,004 8,589 7,728 11,59 14,73 5,30
j ini i
i
S E h k kNm rad
, / 2 3117 /j j iniS S kNm rad
Initial stiffness
Secant stiffness
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Design moment-rotation characteristic
M
Sj,ini
Sj,ini
Sj
Sj= /
Ersatzsteifigkeit:
M j,Rd
2/3Mj,Rd
Secant stiffness
Design of Structural Steel Joints
• Introduction
• Integration of joints into structural design process
• Moment resistant joints
• Simple joints• Design tools
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Nominally pinned joints
Braced frame
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Nominally pinned joints
V 0 M = 0
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Design of simple joints
ECCS Publication No 126 (EN)
• Background information
• Design guidelines
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Classification and modelling of joints
Limits for classification of joints by stiffness
Nominally pinned
Semi-rigid
RigidMj
Initial stiffness of the joint
Sj,ini <<
“Nominally pinned” joints :
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Classification and modelling of joints
Sj,ini
Limits for classification of joints by stiffness
Nominally pinned
Semi-rigid
RigidMj
Initial stiffness of the joint
“Semi-rigid” joints :
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Classification and modelling of joints
As an alternative to a semi-continuous modelling (semi-rigid joints), is it safe to
model the joints as nominally pinned whilst they are actually semi-rigid?
Semi-rigid Sj,ini > 0,5EIb/Lb
Partial strength Mj,Rd > 0,25 Mfull-strength
Nominally pinned Sj,ini = 0
Nominally pinned Mj,Rd = 0??
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Classification and modelling of joints
Yes, …under the reservation the joint has:
• a sufficient rotation capacity
= capacity to “rotate”
• a sufficient ductility
= capacity to follow the actual
loading path in a ductile way
VRd
V
M
Yielding criterionMRd
Supposed
loading path
Actual loading
path
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Supplementary design requirement
Sufficient resistance to «catenary effects» so as to provide required structural
robustness
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Example: Partial depth end-plate
Components
• Bolts in shear
• End-plate in bearing
• End-plate in shear (gross section)
• End-plate in shear (net section)
• End-plate in shear block
• End-plate in bending
• Beam web in shear
• Welds in shear
• Column flange in bearing
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Partial depth end-plate
Strength requirement
• Use of “component method” for the assessment of VRd
Assessment of the strength of all the constitutive components of the joint
+
“Assembly” of these components
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Partial depth end-plate
Rotation capacity requirement
Bending moment
Rotationavail
Contact between supported beam and supporting element
Compression force
Bendingmoment
Bolts in tension
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Partial depth end-plate
Rotation capacity requirement
hp
he
tp
hbdb
avail
p bh d
p
avail
e
t
h
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Partial depth end-plate
Ductility requirement
• Prevent premature fracture of the bolts
• Prevent premature fracture of the welds
under unavoidable bending moment in the joint
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Partial depth end-plate
Ductility requirements
• Prevent premature collapse of the bolts
2,8yp
p ub
fd
t f
2,8ycf
p ub
fd
t f for the supporting column
d and fub : diameter and tensile strength of bolts
for the end-plate
Yielding of end-plate prior to tensile fracture of bolts
Design of Structural Steel Joints
• Introduction
• Integration of joints into structural design process
• Moment resistant joints
• Simple joints
• Design tools
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Practical design tools
• Tables of standardized joints
• Dedicated software
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Worked Example Configuration Beam IPE 500 Column HEA 340 End plate connection
Design assumption Rigid joint
Frame analysisMEd = 220 kNm
CoP software used for this example: http://cop.fw-ing.com
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Design resistance: MRd = 196 kNm < 220 kNmClassification: Semi-rigidFailure mode: Column web in compression
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Failure mode:End plate in bending
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Failure mode:Column web panel in shear
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Failure mode:Column web panel in shear
Eurocodes - Design of steel buildings with worked examples Brussels, 16 - 17 October 2014
Failure mode:Column web panel in shear
Design of Structural Steel Joints
Dr. Klaus WeynandFeldmann + Weynand GmbH, Aachen, Germany
Prof. Jean-Pierre JaspartUniversity of Liège, Belgium