Eurocode 4 - 1.2 composite structures

Transcription

EUROCODES
Background and Applications
Brussels, 18-20 February 2008 – Dissemination of information workshop
Some Information
on Eurocode 4 – part 1.2
(mainly from DIFISEK project report)
Joël KRUPPA
CTICM
Coordinator CEN TC 250 / Horizontal Group "FIRE"
1
EUROCODES
Composite slabs & beams
Options
2
Flat concrete slab or
composite slab with
profiled steel sheeting
Shear
connectors
Profiles with or without
Fire protection material
slabs
Reinforcing
bar
Shear
connectors
Optional slab
Stirrups welded
to web of profile
Reinforcing bar
beams
Composite columns
Options
EUROCODES
(a)
(b)
3
(c)
a: steel embedded in concrete (traditional approach)
b: concrete between flanges (f.r. dependent on reinforcement)
c: concrete filled SHS
-
without reinforcement
with reinforcement
(f.r. ca. 30 minutes or less)
(f.r. dependent on reinforcement)
EUROCODES
Calculation procedure thermal response
Composite elements
Non-uniform temperature distribution
Load bearing and (possibly) separating
function
¾ Load bearing capacity
¾ Thermal insulation
¾ Integrity
Options
¾ tabulated data
¾ simple calculation model
¾ advanced calculation model
4
EUROCODES
Tabulated data
(steel and concrete composite members)
Composite
beams
Slab
Concrete
for insulation
5
Composite columns
EUROCODES
Tabulated data and relevant parameters
(composite columns – prEN1994-1-2)
ef
As h
Ac
us
ew
b
us
Standard Fire
Resistance
R30 R60 R90 R120
Minimum ratio of web to flange thickness ew/ef
1
Minimum cross-sectional dimensions for load level
1.1
1.2
1.3
minimum dimensions h and b [mm]
minimum axis distance of reinforcing bars us [mm]
minimum ratio of reinforcement As/(Ac+As) in %
2
2.1
2.2
2.3
3
3.1
3.2
3.3
Standard
fire rating
Load level
0,5
ηfi,t ≤ 0,28
160
-
200
50
4
300
50
3
400
70
4
ηfi,t ≤ 0,47
160
-
300
50
4
400
70
4
-
ηfi,t ≤ 0,66
160
40
1
400
70
4
-
-
Section
dimension
Reinforcing
steel
Concrete
cover
6
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Composite Beams
7
EUROCODES
Totally encased steel sections
8
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How to apply tabulated data in fire design
(two different situations)
VERIFICATION
PRE-DESIGN
Rd of θ20°C
Efi.d and Ed
Efi.d
ηfi,t = Efi.d / Ed
ηfi,t = Efi.d / Rd
Standard fire rating
Section dimension
reinforcing steel
concrete cover
Section dimension
reinforcing steel
concrete cover
Standard fire rating
Rd ≥ E d
9
EUROCODES
Concrete with only insulation function
10
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Composite elements
Calculation rules thermal response
Similar to concrete elements
Complications due to shape
Simple calculation rules available
11
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Thermal response composite elements
Advanced model (illustration)
12
1200
temperature
[°C]
Temperatuur
[0 C]
==>
G
computer simulation
1000
A
F
E
B
D
C
B
A
800
C
600
D
400
E
F
200
G
0
0
30
60
90
120
time [min]
Tijd [min] ==>
test vs. simulation
EUROCODES
Composite elements
Simple calculation models thermal response
Semi-empirical approach
Parameter study based on systematic
calculation with advanced calculation model
Direct application of advanced calculation
model
13
Simple calculation models
Semi-empirical approach
EUROCODES
14
b
Z
ef
u1
Y
bc,fi
h
h w,fi
u2
bc,fi
ew
Reduced cross section
Components cross section:
flanges steel section
web steel section
concrete
re-bars
For each component:
reduced strength
and/or
reduced area
Simple calculation models
Parameter study approach
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15
¾ Composite slabs with profiled steel sheet
Decking type
re-entrant (6x)
trapezoidal (49x)
(LWC)
Concrete depth
HB [mm]
50, 60, 70, 80,
90, 100, 110, 120
Concrete type
NCW and LWC
ENV 1994-1-1
standard fire conditions
profiled shape deckings taken into account
thermal properties according to EC
average moisture content: 4% (NWC) and 5%
Note: total number of simulations: 880
EUROCODES
Typical temperature distribution at the unexposed
side of a composite slab
16
temperature [°C]
Insulation criterion:
average
-ΔΘav
≤ 140 ºC
-ΔΘ max ≤ 180 ºC
Composite slabs
Thermal insulation (illustration)
EUROCODES
17
Issues:
h1
tf = tf (l1, l2, …, A/Lr, φ)
h2
l3
l2
l1
A
Lr
with:
l1, l2, ..
A
Lr
φ
geometry slab
volume rib
exposed surface rib
configuration factor
tf = a0 + a1·h1 + a2· φ + a3·A/Lr + a4·1/L3 + a5·A/Lr·1/l3 [min]
with:
ai coefficients, depending on duration of s.f.c. exposure
Thermal insulation composite slabs
Verification simple calculation rule
EUROCODES
1.25
Unsafe
Fire resistance (new rule)
Fire resistance (adv. model)
Fire resistance (Eurocode 4)
Fire resistance (adv. model)
.
[-] ==>
.
[-] ==>
1.50
1.00
Safe
0.75
0.50
30
60
90
120
μ
0.962
σ
0.148
150
180
210
18
1.50
1.25
Unsafe
1.00
Safe
0.75
0.50
30
60
90
120
μ
1.015
σ
0.073
150
180
210
Fire resistance (adv. model) [min] ==>
Fire resistance (adv. model) [min] ==>
(a) ENV rule
(b) new rule
Composite slabs
Thermal response positive reinforcement
EUROCODES
19
compression zone
concrete (20 °C)
z
u2
u3
u1
Temperature reinforcement
has significant impact on M+p,Θ
Θr = Θr (u1 , A/O, l3, z ..)
z = z(u1, u2,u3)
Note: steel sheet may significantly contribute to the
load bearing capacity!
EUROCODES
Thermal response positive reinforcement
Simple calculation rule
1.50
1
/2L3
u1
O
α
A
Temperature (EC 4)
Temperature (adv. model)
/2L3
H
safe
1.25
1
Temperature (new rule) .
Temperature (adv. model) [-] ==>
.
[-] ==>
1.50
20
1.00
unsafe
0.75
0.50
350
450
μ
0.913
σ
0.082
550
650
750
u1
O
α
A
1.00
unsafe
0.75
0.50
350
450
μ
0.981
σ
0.032
550
650
0
0
Temperature (adv. model) [ C] ==>
(a) ENV rule
H
safe
1.25
Temperature (adv. model) [ C] ==>
(b) new rule
750
EUROCODES
Composite slabs
h3
h1
h2
heff
l2
l1
21
h3
h1
h2
l3
l1
l3
chape
béton
tôle d'acier
l2
Thermal Insulation
(ISO fire)
I 30
Equivalent thickness
heff[mm]
60 – h3
I 60
80 – h3
I 90
100 – h3
I 120
120 – h3
EUROCODES
Concrete filled SHS columns
Resistance to fire (traditional approach)
Design charts available
Unpractical
Need for “user friendly” design
tool
⇒ e.g. POTFIRE
no. concrete rebar
quality
1
C20
2
C20
3
C20
4
C30
5
C30
6
C30
7
C40
8
C40
9
C40
%
1.0
2.5
4.0
1.0
2.5
4.0
1.0
2.5
4.0
22
EUROCODES
input
POTFIRE
In- & output
output
23
Validation POTFIRE
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temperature test
24
1100
assumptions:
1000
- αconv = 25 W/m2k
900
800
- εres
700
= 0.7
600
500
400
Concrete Filled
Steel Hollow Section
300
200
100
0
0
100
200
300
400
500
600
700
800
900
1000 1100
temperature (Potfire)
EUROCODES
Logiciels de calcul
Logiciels
« AFcolumn » et
« AFbeam »
Développés par
ProfilARBED
Peuvent être obtenus
sur le site
www.arcelormittal.com
25
EUROCODES
Simple calculation model
(steel and composite members)
Beams (steel or
composite)
26
Columns
EUROCODES
Simple calculation model (composite beam)
- plastic resistance theory
27
Concrete slab
S1
Steel section
Connector
S1
Section S1
+
Fc
-
D+
+
+
Ft
Section
geometry
Temperature
distibution
Stress
distribution
Moment
resistance
+
Mfi,Rd+ = Ft × D
+
EUROCODES
Composite beams
28
b eff
hc
b2
e2
ew
h
hw
e1
b1
¾bare
3 0 m in
température [°C]
1000
800
1 5 m in
600
400
200
0
0
100
200
300
400
500
fa c te u r d e m a ssive té [m -1]
¾insulated
15 m m
1000
l'acier [°C]
température de
E C H A U F F E M E N T : 9 0 m in .
20 m m
800
600
400
25 m m
30
35
40
45
50
55
200
0
0
100
200
300
400
fa c te u r d e m a s s iv e té ( S / V e n m - 1 )
m
m
m
m
m
m
EUROCODES
Simple calculation model (composite column)
- buckling curve
P
Aai
Acj
Lfi
Z
1.0
χ(λθ)
Y 0.5
Ask
0
Effective section
Appropriate
buckling curve
Load capacity: Nfi.Rd = χ(λθ) Nfi.pl.Rd
χ(λθ) ⇐ strength and rigidity of effective section +
column buckling length Lfi
λθ
29
Construction details shall be respected in order to
EUROCODES
consistent with numerical models
Reinforcing bars
between slab
and edge
columns
φ12 in S500
Maximum gap of 15
mm between beam
and column and
between lower
flange of the beam
gap
gap ≤ 15 mm
30
EUROCODES
Construction details to get hogging moment
resistance in fire situation
Join detail - Example
Continuous
reinforcing bar
studs
gap
Sections with
infilled concrete
A limited gap
allowing to
develop a
hogging
moment in the
fire situation
31
EUROCODES
Construction details for connection between
concrete and steel
Connection between steel profile and encased concrete
φr ≥ 8 mm
φs ≥ 6 mm
welding
aw ≥ 0,5 φs
hν
studs
d ≥ 10 mm
hν ≥ 0,3b
lw ≥ 4 φs
φr ≥ 8 mm
b
Welding of stirrups
to the web
Welding of studs to
the web
32
EUROCODES
Fire design by global structural analysis
Application requirement of advanced calculation models
¾requirement on material models
• strain composition
• kinematical material model
• strength during cooling phase
¾step by step iterative solution procedure
¾check of possible failure untreated in direct analysis
• rupture due to excessive steel elongation
• cracking and crushing of concrete
33
EUROCODES
Global analysis of steel and concrete composite floor
under localised fire
34
Composite slab
Steel deck: 0.75 mm
Standard part of the
floor system
3.2 m
4.2 m
15 m
10 m
15 m
10 m
10 m
15 m
EUROCODES
Choice of structural model
Two different structural models may be adopted
¾2D composite frame model (beam elements)
• membrane effect is limited to one direction
due to 1D effect slab model
• load redistribution is not possible between
parallel beams
¾3D composite floor model (multi-type
element)
• membrane effect over whole floor area
• load redistribution becoming possible with
help of shell elements
More realistic to apply 3D composite floor model
35
EUROCODES
Validity of 3D composite floor model
Test
3D calculation model
36
Hori. Disp. (mm) Vert. Disp. (mm)
0
0
15
Time (min)
30
45
60
75
-40
-80
-120
-160
Test
Cal. 3D
Cal. 2D
-200
60
40
20
0
0
20
40
Time (min)
60
80
EUROCODES
Strategy of 3D composite floor modelling
37
Fire area
Global structure without
composite slab
Detail of
numerical
modelling
EUROCODES
Mechanical loading and boundary conditions
38
Uniformly distributed load: G + Ψ1,1Q
θ=0
Continuity condition
of concrete slab
θ=0
Continuity
condition of
columns
EUROCODES
Mechanical response of the structure
39
¾Total deflection of the floor and check of the
corresponding failure criteria
140 mm
20 min
310 mm
40 min
EUROCODES
40
¾Total deflection of the floor and check of the
corresponding failure criteria
110 mm ≤ L/20 = 500 mm
230 mm
Deflection (mm)
0
- 50
-100
-150
-200
Main beam
-250
-300
60 min
Secondary
beam
0
10
20
30
40
50
Time (min)
280 mm ≤ L/20 = 750 mm
60
EUROCODES
41
¾Check of failure criteria: elongation of reinforcing steel
1.4 % ≤ 5 %
1.3 % ≤ 5 %
Strain of reinforcing steel
// slab span
Strain of reinforcing steel
⊥ slab span
EUROCODES
Unbraced frame – R + 3
42
EUROCODES
Design
43
1.0 G + 0.3 Q
1.0 G + 0.3 Q
1.0 G + 0.3 Q
1.0 G + 0.3 Q
1.0 G + 0.3 Q
1.0 G + 0.3 Q
1.0 G + 0.3 Q
1.0 G + 0.3 Q
0.5 W
0.5 W
0.5 W
Unbraced frame
Edge column temperature
EUROCODES
Time : 90 minutes
44
955
926
845
750
671
606
553
510
475
448
428
413
405
403
405
413
428
448
475
510
553
606
671
750
845
926
955
Y
X
Temperature (°C)
956
927
847
753
675
611
558
516
482
455
435
420
412
409
412
420
435
455
482
516
558
611
675
753
847
927
956
957
929
851
759
683
621
570
529
496
469
449
435
426
423
426
435
449
469
496
529
570
621
683
759
851
929
957
958
931
855
767
694
636
589
550
517
491
471
457
448
446
448
457
471
491
517
550
589
636
694
767
855
931
958
960
934
860
775
707
655
614
578
546
518
498
485
477
474
477
485
498
518
546
578
614
655
707
775
860
934
960
963
937
866
782
714
674
654
619
578
551
532
519
511
509
511
519
532
551
578
619
654
674
714
782
866
937
963
966
941
873
791
718
683
680
654
614
590
573
561
554
552
554
561
573
590
614
654
680
683
718
791
873
941
966
969
947
884
807
729
686
683
674
655
637
623
613
607
606
607
613
623
637
655
674
683
686
729
807
884
947
969
973
954
901
835
770
729
718
714
707
695
685
677
672
671
672
677
685
695
707
714
718
729
770
835
901
954
973
1000
A
External Column
A
900
B
800
C
700
B
600
500
400
C
300
200
100
0
0
10
20
30
40
50
60
70
80
Time (min)
90
977
963
923
875
835
807
791
782
775
767
760
755
751
750
751
755
760
767
775
782
791
807
835
875
923
963
977
981
972
950
923
901
884
873
866
860
855
851
848
846
845
846
848
851
855
860
866
873
884
901
923
950
972
981
983
980
972
963
954
947
941
937
934
931
929
927
926
926
926
927
929
931
934
937
941
947
954
963
972
980
983
983
983
981
977
973
969
966
963
960
958
957
956
955
955
955
956
957
958
960
963
966
969
973
977
981
983
983
Central column temperature
EUROCODES
45
954
924
842
745
663
595
538
487
443
407
378
354
335
320
308
300
296
294
294
296
301
308
320
335
354
378
408
444
488
538
595
663
745
843
925
955
Y
X
955
925
844
748
667
600
544
494
451
415
386
362
343
328
316
309
305
303
303
305
309
317
328
343
362
386
415
451
494
544
600
667
748
845
926
955
956
927
847
753
675
610
556
508
465
430
401
378
359
344
333
327
324
323
323
324
327
333
344
359
378
401
430
466
508
556
611
676
754
848
927
956
957
930
852
762
687
627
576
530
488
453
425
402
384
369
359
354
353
353
353
353
354
359
369
384
402
425
454
489
531
576
627
688
762
853
930
957
959
932
858
770
700
647
603
561
519
483
455
432
415
401
392
389
391
395
395
391
389
392
401
415
433
455
483
519
561
603
647
700
770
858
933
959
962
936
863
778
708
666
645
604
553
518
491
469
453
440
431
427
439
451
451
439
427
431
440
453
470
491
518
553
604
645
667
708
778
864
936
962
965
940
871
787
712
676
673
640
592
560
535
516
500
488
478
472
478
487
487
478
472
478
488
500
516
536
560
592
640
673
676
713
787
871
940
965
968
946
882
803
723
679
676
663
637
611
590
573
559
547
536
526
507
492
492
507
526
536
547
559
573
590
611
637
663
676
679
723
803
883
946
968
Temperature (°C)
Central Column
1000
A
900
A
800
700
B
B
600
D
500
D
400
300
C
200
100
0
0
10
20
30
40
50
60
70
80
90
Time (min)
C
972
953
899
832
765
723
712
705
692
674
657
643
631
620
609
596
570
549
549
570
596
609
620
631
643
657
674
692
705
712
723
765
832
899
953
972
976
962
922
872
832
803
785
774
763
751
739
728
718
709
699
687
673
664
664
673
687
699
709
718
728
739
751
763
774
785
803
832
872
922
962
976
980
972
949
922
899
882
869
860
852
844
837
830
824
817
811
804
796
792
792
796
804
811
817
824
830
837
844
852
860
870
882
899
922
949
972
980
983
980
972
962
953
945
939
933
929
925
921
917
913
910
907
903
900
899
899
900
903
907
910
913
917
921
925
929
934
939
945
953
962
972
980
983
983
983
980
976
972
967
963
960
957
954
951
948
946
943
941
939
938
937
937
938
939
941
943
946
948
951
954
957
960
963
967
972
976
980
983
983
Bean-slab temperature
EUROCODES
38
41
44
49
54
61
66
66
68
72
76
81
86
92
99
107
118
131
147
165
185
209
236
266
301
340
383
433
489
552
624
705
799
860
39
41
45
49
54
61
66
66
68
71
75
80
85
91
97
103
111
120
135
154
175
199
225
254
287
325
367
416
472
536
612
701
810
876
41
44
47
51
56
62
66
66
68
72
76
81
86
92
97
101
104
110
125
145
165
188
212
240
271
306
346
393
449
516
598
700
828
903
46
49
52
56
60
64
67
67
71
79
86
92
97
102
107
114
123
133
146
163
182
202
224
249
278
311
349
395
451
518
603
709
843
921
55
59
63
67
72
76
80
83
89
98
109
120
129
138
148
159
173
186
199
213
229
246
266
288
314
344
380
424
477
543
625
729
859
934
68
74
80
86
92
99
110
122
132
144
159
176
193
209
225
240
255
269
283
297
311
327
343
363
385
412
444
483
531
591
666
760
878
946
87
94
103
116
130
144
163
182
200
220
242
265
289
314
339
363
384
402
417
430
443
456
469
485
503
524
551
583
622
671
732
808
903
958
115
127
144
166
192
218
247
274
300
327
354
385
424
473
525
568
598
617
630
641
650
659
668
678
690
704
721
741
766
797
835
881
937
969
143
162
187
217
251
289
329
367
400
432
463
495
534
627
750
815
836
847
855
860
864
868
872
876
881
887
894
902
912
925
940
957
971
977
168
191
222
260
307
361
419
471
512
546
576
603
624
46
195
224
262
310
373
454
570
645
679
721
745
762
771
230
266
315
378
461
575
753
270
315
374
449
546
673
849
294
344
407
485
582
703
861
300
352
416
494
590
709
865
302
354
418
496
592
710
865
303
354
418
496
592
711
865
303
354
418
496
592
711
865
303
354
418
496
592
711
865
Y
X
Temperature
Beam
(°C)
1000
A
900
800
D
C
700
600
500
B
400
300
A
200
B
C
D
100
0
0
10
20
30
40
50
60
70
80
90
Time (min)
EUROCODES
Deformations of the frame
47
Horizontal displacement HD (mm)
160
140
120
100
80
60
40
20
0
0
10
20
30
40
50
60
Time (min)
Y
X
HD
70
EUROCODES
Braced frame
48
1.0 G + 0.5 Q
1.0 G + 0.5 Q
1.0 G + 0.5 Q
1.0 G + 0.5 Q
1.0 G + 0.5 Q
1.0 G + 0.5 Q
1.0 G + 0.5 Q
1.0 G + 0.5 Q
Braced frame
EUROCODES
Deformation of frame
0
0
49
10
20
-50
-100
-150
-200
-250
-300
-350
VD
-400
Vertical displacement VD (mm)
Y
X
30
40
Time (min)
50
60
EUROCODES
Comparison
N ° o f
ca se
a se 1
R e s tr a in t
c o n d itio n
u n b ra ced
φ 16
u n b ra ced
200
φ20
o f b ea m
m in u te s
4 4 .5
280
300
m in u te s
300
200
φ20
6 0 .5
280
300
m in u te s
300
200
φ20
200
F ir e r e s is ta n
o f th e fra m
3 7 .5
280
300
φ 16
300
u n b ra ced
d im e n s io n
300
200
200
a se 3
d im e n s io n o f
c e n t r a l c o lu m n
200
200
a se 2
50
d im e n s io n o f
e x t e r n a l c o lu m n
φ20
1000
a se 4
300
u n b ra ced
200
a se 5
φ20
b ra ced
200
φ 16
4 7 .5
280
300
m in u te s
300
200
6 4 .0
m in u te s
300
φ20
200
200
70
269
300
φ 16
1000
a se 6
200
b ra ced
200
70
269
300
φ 16
200
φ 16
300
6 0 .0
m in u te s

Eurocode 4 - 1.2 composite structures

Transcription

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