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NEESR-SG: Controlled Rocking of Steel-Framed Buildings with Replaceable Energy Dissipating Fuses. Gregory G. Deierlein, Sarah Billington, Helmut Krawinkler, Xiang Ma Stanford University Jerome F. Hajjar, Matthew Eatherton University of Illinois at Urbana-Champaign - PowerPoint PPT Presentation
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International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
NEESR-SG: Controlled Rocking of Steel-Framed Buildings with Replaceable Energy Dissipating Fuses
Gregory G. Deierlein, Sarah Billington, Helmut Krawinkler, Xiang Ma Stanford University
Jerome F. Hajjar, Matthew Eatherton University of Illinois at Urbana-Champaign
Mitsumasa Midorikawa, Hokkaido University
Toru Takeuchi, Tokyo Institute of Technology
T. Hikino, Hyogo Earthquake Engineering Research CenterDavid Mar, Tipping & Mar Associates and Greg Luth, GPLA
In-Kind Funding: Tefft Bridge and Iron of Tefft, IN, MC Detailers of Merrillville, IN, Munster Steel Co. Inc. of Munster, IN, Infra-Metals of Marseilles, IN, and Textron/Flexalloy Inc. Fastener Systems
Division of Indianapolis, IN.
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
Throw-away technology:Structure and Architecture absorbs energy through damage
Large Inter-story Drifts:Result in architectural & structural damage
High Accelerations:Result in content damage& loss of function
Deformed Section – Eccentric Braced Frame
Key Short Comings of Modern Seismic Design
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
New System
Develop a new structural building system that employs self-
centering rocking action and replaceable* fuses to provide
safe and cost effective earthquake resistance. *Key Concept – design for repair
Post-tensioning
Shear Fuse
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
Component 1 – Stiff braced frame, designed to remain essentially elastic - not tied down to the foundation.
Component 2 – Post-tensioning strands bring frame back down during rocking
Component 3 – Replaceable energy dissipating fuses take majority of damage
Bumper or Trough
Controlled Rocking System
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
Bas
e S
hea
r
Drift
a
b c
d
f
g
Combined System
Origin-a – frame strain + small distortions in fusea – frame lift off, elongation of PTb – fuse yield (+)c – load reversal (PT yields if continued)
d – zero force in fusee – fuse yield (-)f – frame contactf-g – frame relaxationg – strain energy left in frame and fuse, small residual displacement
Fuse System
Bas
e S
hea
r
Drift
a
b c
d
efg
Fuse Strength Eff. FuseStiffness
PT Strength
PT – Fuse Strength
Pretension/Brace SystemB
ase
Sh
ear
Drift
a,f b
cde
g PT Strength
Frame Stiffness
e
2x FuseStrength
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
Rocking Braced Frame w/Post Tensioning
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
Panel Size: 400 x 900 mm
• Attributes of Fuse– high initial stiffness
– large strain capacity
– energy dissipation
• Candidate Fuse Designs– ductile fiber cementitious
composites
– steel panels with slits
– low-yield steel
– mixed sandwich panels
– damping devices
Phase I: Shear Fuse Testing
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
Fuse Configurations
B
L
b
thickness t
h
a
Rectangular link: b/t and L/t Butterfly link: b/a
Welded end Buckling-restrained
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
Testing Results: Butterfly Links
B36-10 B56-09
B37-06 B14-02
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
B36-10 B56-09
B37-06 B14-02
Butterfly Links: Load-Deformation
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
Phase II: Half-Scale System Tests
In the Rig
General Specimen Design
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
Reaction Wall
Loading and Boundary Condition Box (LBCB)
Bumpers Restrain Horizontal Movement
(Not Shown Here)
Load Cell Pins Provide Load Data and
Feedback for Control
Anchorage Plate for the Post-Tensioning
Loading Beam Applies Loads to the Two
Frames
Test Setup at MUST-SIM FacilityNetwork for Earthquake Engineering Simulation (NEES)
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
Test MatrixTest ID
Dim “B”
A/B Ratio
OT Ratio
SC Ratio
Num. of 0.5” P/T Strands
Initial P/T Stress2 and
Force
Fuse Type and Fuse Strength
Fuse Configuration Testing Protocol
A1 2.06’ 2.5 1.0(R=8)
0.8 8 0.287 Fu(94.8 kips)
Steel Butterfly 1
(84.7 kips)
Six – 1/4” thick fuses3F-025-AB2.5-OT1.0
Quasi-Static
A2 2.06’ 2.5 1.0(R=8)
0.8 8 0.287 Fu(94.8 kips)
Steel Butterfly 2
(84.7 kips)
Two – 5/8” thick Fuses1F-0625-AB2.5-OT1.0
Quasi-Static
A3 2.06’ 2.5 0.85(R=9.4)
1.1 8 0.287 Fu(94.8 kips)
Steel Butterfly 3
(62.0 kips)
Two – 5/8” thick Fuses1F-0625-AB2.5-OT0.85
Quasi-Static
A4 2.06’ 2.5 1.5(R= 5.3)
0.8 8 0.430 Fu(142.3 kips)
Steel Butterfly 3
(127.0 kips)
Two – 1” thick Fuses1F-1-AB2.5-OT1.5
Quasi-Static
B1 3.06’ 1.69 1.0(R=8)
0.8 7 0.328 Fu(94.8 kips)
Steel Butterfly 4
(75.4 kips)
Six – 1/4” thick fuses3F-025-AB1.69-OT1.0
Quasi-Static
B2 3.06’ 1.69 1.0(R=8)
0.8 7 0.328 Fu(94.8 kips)
Steel Butterfly 5 (75.4 kips)
Two – 5/8” thick Fuses1F-0625-AB1.69-OT1.0
Quasi-Static
B3 3.06’ 1.69 1.0(R=8)
0.8 7 0.328 Fu(94.8 kips)
Steel Butterfly 4a
(75.4 kips)
Six – 1/4” thick fuses3F-025-AB1.69-OT1.0
Hybrid Simu-lation
B4 3.06’ 1.69 1.5(R= 5.3)
0.8 7 0.492 Fu(142.3 kips)
Steel Butterfly 6
(113.2 kips)
Two – 1” thick Fuses1F-1-AB1.69-OT1.5
Quasi-Static
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
Tested Configurations
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
Test Results – Hysteretic Behavior
-4 -3 -2 -1 0 1 2 3 4-150
-100
-50
0
50
100
150
Roof Drift Ratio (%)
App
lied
For
ce (
kips
)
Preliminary Analytical Model
Experimental Response
-4 -3 -2 -1 0 1 2 3 4-150
-100
-50
0
50
100
150
Roof Drift Ratio (%)
App
lied
For
ce (
kips
)
Preliminary Analytical Model
Experimental Response
Test A1 Test A2
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
-4 -3 -2 -1 0 1 2 3 4-150
-100
-50
0
50
100
150
Roof Drift Ratio (%)
App
lied
For
ce (
kips
)
Complete Response
Load Step 9
Load Step 12
-3 -2 -1 0 1 2 3 4-150
-100
-50
0
50
100
150
Roof Drift Ratio (%)
App
lied
For
ce (
kips
)
Complete Response
Load Step 9
Load Step 12
Test Results – Fuse Link Buckling
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
Test Results – Post Tensioning Force
-4 -3 -2 -1 0 1 2 3 450
100
150
200
250
300
Roof Drift Ratio (%)
Pos
t-T
ensi
on F
orce
(ki
ps)
Left Frame
Right Frame
Predicted for Left Frame
Predicted for Right Frame
-3 -2 -1 0 1 2 3 450
100
150
200
250
300
Roof Drift Ratio (%)
Pos
t-T
ensi
on F
orce
(ki
ps)
Left Frame
Right Frame
Predicted for Left Frame
Predicted for Right Frame
Test A1 Test A2
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
Test Results – Left Frame Column Uplift
-4 -3 -2 -1 0 1 2 3 4-0.5
0
0.5
1
1.5
2
2.5
Roof Drift Ratio (%)
Col
umn
Upl
ift (
in)
Left Column of Left Frame
Right Column of Left Frame
Prediction for Left Column of Left Frame
Prediction for Right Column of Left Frame
-3 -2 -1 0 1 2 3 4-0.5
0
0.5
1
1.5
2
2.5
Roof Drift Ratio (%)
Col
umn
Upl
ift (
in)
Left Column of Left Frame
Right Column of Left Frame
Prediction for Left Column of Left Frame
Prediction for Right Column of Left Frame
Test A1 Test A2
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
Test Results – Fuse Shear Strain
0 2000 4000 6000 8000 10000-15
-10
-5
0
5
10
15
Substep Number
Fus
e S
hear
Str
ain
(%)
Measured Fuse Shear Strain
Target Fuse Shear Strain
0 2000 4000 6000 8000 10000-15
-10
-5
0
5
10
15
Substep Number
Fus
e S
hear
Str
ain
(%)
Measured Fuse Shear Strain
Target Fuse Shear Strain
Test A1 Test A2
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
Test Frame Test-bed Unit
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
Controlled Rocking System Test at E-Defense (2009)
Large (2/3 scale) frame assembly
Validation of dynamic response and simulation
Proof-of-Concept
construction details
re-centering behavior
fuse replacement
Collaboration & Payload Projects
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
Conclusions •The controlled rocking system exhibits excellent self-centering and
energy dissipating response. All indicators show that the system is constructable and viable for practice.
•The controlled rocking system will reduce life cycle costs by reducing structural repair costs after an earthquake.
•Butterfly steel plate shear fuses, tested at Stanford University, were able to sustain cyclic deformations as large as 25% shear strain or more and still absorb seismic energy.
•Half scale tests at University of Illinois are in progress. Tests A1, A2, and A3 are complete. More tests to come.
•Two-thirds scale shake table tests on a planar frame at E-Defense next summer will further validate system performance.
•Design recommendations will be develoeped to allow implementation in practice.
International Association for Bridge and Structural Engineering
Creating and Renewing Urban Structures
Video of Specimen A1Six ¼” fuses buckled late in the loading history; Peak drift: 3%; Peak shear strain:
11%
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