Joints play an important role in providing ductility for steel-composite structures subject to extreme loading conditions, such as blast, fire and impact. Due to sound energy dissipation capability and fabrication efficiency, semi-rigid joints have increasingly received attention during the last decade. This paper presents a component approach for modeling semi-rigid beam-to-column joints based on Eurocode3, where the post-elastic response, including component strain hardening and ultimate rotational capacity, is also considered. Failure criteria are defined based on the ultimate deformation capacity of components and bolt-rows. The model enables a direct integration of joint response into global frame models with the consideration of axial deformability, such that the interaction between bending moment and axial force within the joints can be realistically captured. In addition, elevated temperature can be considered in the joint model via the degradation of the component response. Through comparisons with available test data, the joint model is shown to have good accuracy, and the failure criteria are found to be reliable yet conservative. The strain hardening response of components is shown to have significant influence on the ultimate bending capacity of the joints, while neglecting it usually leads to a conservative prediction.
. Modeling of semi-rigid beam-to-column steel joints under extreme loading[J]. Frontiers of Structural and Civil Engineering, 2013, 7(3): 245-263.
C FANG, B A IZZUDDIN, A Y ELGHAZOULI, D A NETHERCOT. Modeling of semi-rigid beam-to-column steel joints under extreme loading. Front Struc Civil Eng, 2013, 7(3): 245-263.
component library:(1) column web panel in shear;(2) column web in transverse compression;(3) column web in transverse tension; (4) column flange in bending; (5) column web in bending; (6) end-plate in bending; (7) angle/cleat in bending; (8) angle/cleat/fin plate in tension; (9) angle/cleat/fin plate in compression; (10) angle/cleat in bearing; (11) beam flange/web in compression; (12) beam web in tension; (13) bolts in tension; (14) bolts in shear; (15) bolts in bearing.
zones
flush end-plate joint
top and bottom seat cleat joint
web cleat joint
fin plate joint
tension zone
(3), (4), (6), (12), (13)
(3), (4), (7), (8), (10), (13), (14), (15)
(3), (4), (7), (8), (10), (12), (13), (14), (15)
(3), (8), (10), (12), (14), (15)
compressive zone
(2), (11)
(2), (9), (10), (14), (15)
(2), (9), (10), (14), (15)
(2), (9), (10), (14), (15)
shear zone
(1)
(1)
(1)
(1)
Tab.1
Fig.3
Fig.4
Fig.5
components
bi-linear approach
tri-linear approach
Sim?es da Silva et al.[19]
Lima et al.[20]
Ren and Crisinel [21]
Savio et al. [22]
Jabriet al. [23]
Ramli-Sulong et al. [24]
plastic ì1
Ultimate ì2
column web in shear
4.6%
1.76-7%
6%
50%
21.7%
ì1 = 5%ì2 = 1%
ì1 = 5%ì2 = 1%
column web in compression
2.3%
3.07-9.28%
30%
13%
column web in tension
0.1-1.7%
0.25-15%
30%
13%
column flange in bending
1.3%
0.13-15%
20%
8.7%
endplate in bending
-
0.18-1.84%
10%
4.3%
beam web in tension
-
2.05-3.65%
-
-
beam flange/web in compression
-
0.44-4.89%
-
-
bolt in tension
-
0.49-8%
60%
26.1%
Tab.2
Fig.6
Fig.7
ductility index
component
elasticresistance
elasticstiffness
limit deformation (df/dy)
high ductility
column web in shear
FR,cws=0.9fy,wcAvc3
Kcws=E0.38Avcβ.z
infinite
column web in tension
FR,cwt=ωbeff,t,wctwcfy,wc
Kcwt=E0.7beff,t,wctwcdc
infinite
end-plate in bending
equivalent T-stub model
Kcfb=E0.85lefftfc3m3
infinite
column flange in bending
equivalent T-stub model
Kcfb=E0.85lefftfc3m3
infinite
angle in bending
equivalent T-stub model
Kab=E0.85leff,ata3ma3
infinite
limited ductility
angle plate in bearing
FR,ab=k1abfudta
Kabr=24nbkbktdfu
15
beam web plate in bearing
FR,bwbr=k1abfudtbw
Kbwbr=24nbkbktdfu
15
column web in compression
FR,cwc=ωkwcρbe,ff,c,wctwcfy,wc
Kcwc=E0.7beff,c,wctwcdc
5
brittle failure
bolts in tension
FR,bt=2k2fubAs
Kbt=1.6EAs/Lb
1
bolts in shear
FR,bs=nsαvfubAs
Kbs=16nbd2fubdM16
1
beam flange/web in compression
FR,bfwc=Mc,Rdz
∞
1
Tab.3
temperature/°C
strength SRF
stiffness SRF
20°C
1.000
1.000
100°C
1.000
1.000
200°C
0.971
0.807
300°C
0.941
0.613
400°C
0.912
0.420
500°C
0.721
0.280
600°C
0.360
0.100
700°C
0.160
0.035
800°C
0.110
0.020
900°C
0.060
0.010
1000°C
0.040
0.005
1100°C
0.020
0.0025
1200°C
0.000
0.000
Tab.4
Fig.8
Fig.9
Fig.10
Fig.11
Fig.12
Fig.13
Fig.14
Fig.15
Fig.16
Fig.17
Fig.18
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