machel morrison doug schweizer tasnim hassan (pi)
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Experiments and Simulations of an Innovative Performance Enhancement Technique for Steel Building Beam-Column Connections. Machel Morrison Doug Schweizer Tasnim Hassan (PI). Post Northridge Research. Bolted Extended Endplate. Bolted Flange Plate . - PowerPoint PPT PresentationTRANSCRIPT
Experiments and Simulations of an Innovative Performance Enhancement Technique for Steel
Building Beam-Column Connections
Machel MorrisonDoug Schweizer
Tasnim Hassan (PI)
Post Northridge ResearchAISC 341 Performance Criteria θd =0.04 Radians
Bolted Extended Endplate Bolted Flange Plate
Kaiser Bolted Bracket Reduced Beam SectionWUF-W
Figures from Hamburger et. al 2009
Heat Treated Beam Section (HBS)
Mf ∝ MRBS
Mf ∝ MHBS
Heat Treated Beam Section (HBS)
Time (min)
Air Cool
Slow Cool
Tem
p ˚C
Figure from :http://textbooks.elsevier.com
0% 10% 20% 30% 40% 50% 60%0
10
20
30
40
50
60
70Uniaxial Tension Stress-Strain Response (A992)
Unconditioned 700 C
800 C 1050 C
1050 C Slower cooling rate
εx (%)
σx (ksi)
Induction Heating- Eddy currents “induced” by alternating magnetic field
Advantages: •Lower energy Input than traditional heating sources
•Easy to localize heat input
Induction heating provided by Ameritherm Inc.
Induction HeatingChallenges:
-Difficult to control temperature uniformity
-Prescribed slow cooling rate was not achieved
Experimental Program-4 Full Scale WUF-W
-3 HBS and 1 Unconditioned
-Sub assemblage similar to Engelhardt et al 1998- DB5
Experiment Results
0
20000 HBS -Cyclic Response
Interstory Drift θ (radians)
Mom
ent (
in-K
ip)
00 0.02 0.04 0.06
0
10
20
30
40 Cyclic Response of HBS & WUF-W
WUF-W
HBS
Interstory Drift θ (radians)
M(x 1000 in-Kip)
HBS
Experiment Results WUF-W HBS
HBS
Experiment ResultsWUF-W
Challenges-Significant yielding spread beyond HBS region and higher moments than expected
0 0.1 0.2 0.3 0.4 0.50
20
40
60
80
UnconditionedInduction Heat treatedFurnace Heat treated
εx (in/in)
σx (ksi)
Uniaxial Tension Stress-Strain Response (A992)
FE Simulations
-Finite Strain, Large Displacement Formulation
-Initial Geometric Imperfections (Flange thickness variation, out of straightness)
-Quadratic Shell Elements
ANSYS 12.1 Mechanical ADPL
FE Simulation- Constitutive Model-Non Linear Kinematic Hardening Model (Chaboche 1986)
23
p pi i i ida C d a d
1 23
2( ) [ ( ) ( )] 0of s a s a s a
Chaboche Kinematic Hardening Rule
4
1i
i
da da
p fd d
-1.5 -1 -0.5 0 0.5 1 1.5
-80
-60
-40
-20
0
20
40
60
80
Experiment
Chaboche Model
σx (ksi)
εx (%)
A992 Beam FlangeYield Surface
Flow Rule-0.05 -0.04 -0.03 -0.02 -0.01 0 0.01 0.02 0.03 0.04 0.05
-80
-60
-40
-20
0
20
40
60
80σx (ksi)A572 Gr 50
εx (in/in)
Experiment results from Kaufmann et. al 2001
Chaboche Model
Experiment
Validation of FE Simulation
-0.05 -0.03 -0.01 0.01 0.03 0.0500000000000001
-40
-20
0
20
40Cyclic Response of WUF-W
WUF-W Expt Response
WUF-F Simulation (Chaboche)
M (x 1000 in-Kip)
θ-0.05 -0.03 -0.01 0.01 0.03 0.0500000000000001
-40
-20
0
20
40Cyclic Response of HBS
HBS Experiment Response
HBS Simulation
M (x1000 in-Kip)
θ
Validation of FE Simulation
-5 -3 -1 1 3 5
-1500
-1000
-500
0
500
1000
1500Strain Profiles
εx (microstrain)
Position along flange (in.)
Tension Flange
Compression Flange Experiment Simulation
0.005 Rads
0.00375 Rads
0.0075 Rads
0.005 Rads
0.00375 Rads
WUF-W
FE Simulation Results
-6 -4 -2 0 2 4 6
-0.30
-0.25
-0.20
-0.15
-0.10
-0.05
0.00
0.05
Compression Flange
Position along Flange (in)
0.01 Rads
0.02 Rads
0.03 Rads
εpx (%)
Furnace HT Proper-ties
Induction HT Prop-erties
Expt Results- Flange Buckling HBS WUF-W
Validation of FE Simulation
FE Results- Flange Buckling
0 5 10 15 20 25 30
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
Local Flange Buckling WUF-W
WUF-W Simulation
WUF-W Experiment Results
Distance from Column Face (in)
δ (in)
FE Results- Flange Buckling Shear tab w/Supplemental Weld
No Shear tab/Supplement weld
FE Results- Flange Buckling
0 5 10 15 20 25 30
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5 Local Flange Buckling WUF-W
WUF-W Simulation
WUF-W Experiment Results
WUF-W Simulation (No Shear Tab/ Supplemental Weld)
Distance from Column Face (in)
δ (in)
FE Results –Flange Buckling
-6 -4 -2 0 2 4 6
-25
-20
-15
-10
-5
0
5
10
0.04 rads
0.03 rads
0.02 rads
εpx (%)
Compression Flange
Position along flange (in.)
Shear tab w/Supplemental Weld
-6 -4 -2 0 2 4 6
-25
-20
-15
-10
-5
0
5
10 εpx (%)
0.02 rads 0.03
rads 0.035 rads
0.04 rads
Compression Flange
Position along flange (in.)
No shear tab/Supplemental weld
WUF-WWUF-W
Ricles et. al 2002
Summary-Heat treatment of beam flanges reduces strength of steel and initiates yielding in the heat treated regions
-Future experiments are being planned with new heat treatment technique
-Uniform heat pattern difficult to achieve with Induction heating, σ-ε response varied from furnace heat treatment
-Heavy shear w/supplemental fillet weld to beam web influences local flange buckling
Acknowledgments-National Science Foundation (NSF)
-Network for Earthquake Engineering Simulation (NEES)
-MAST LAB @ U of Minnesota
-Lejune Steel Company
-Ameritherm Inc.
New Heat treatment Technique
0 0.1 0.2 0.3 0.4 0.5 0.60
20
40
60
80
Unconditioned
Induction Heat treated
New Heat treatment Method
εx (in/in)
σx (ksi)
Uniaxial Tension Stress-Strain Response (A992)
COMPARISON WUF-W, HBS & RBSWUF-W No Shear tab/Supplemental weld
HBS No Shear tab/Supplemental weld
RBS No Shear tab/Supplemental weld
COMPARISON WUF-W, HBS & RBS
WUF-W
From Hassan and Syed 2009
Moment Response
-0.05 -0.03 -0.00999999999999998 0.01 0.03 0.0500000000000001
-40
-20
0
20
40Cyclic Response of WUF-W
WUF-W
WUF-W Simulation (Multilinear)
M (x 1000 in-kip)
θ
Moment Response
0 0.02 0.04 0.060
10
20
30
40Cyclic Response of HBS & WUF-W
WUF-W Expt
WUF-W Simulation
HBS Expt
HBS Simualtion Induction HT
HBS Simulation Improved HT
Interstory Drift θ (rad)
M(x 1000 in-Kip)