Transcript NEESR-SG: Controlled Rocking of SteelFramed Buildings with Replaceable Energy Dissipating Fuses Greg Deierlein, Paul Cordova, Eric Borchers, Xiang Ma, Sarah Billington, & Helmut.

NEESR-SG: Controlled Rocking of SteelFramed Buildings with Replaceable
Energy Dissipating Fuses
Greg Deierlein, Paul Cordova, Eric Borchers, Xiang Ma, Sarah
Billington, & Helmut Krawinkler, Stanford University
Jerome Hajjar & Kerry Hall, University of Illinois
Mitsumasa Midorikawa, Hokkaido University
David Mar, Tipping & Mar Associates
Shortcomings of Current Approaches
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
Objective
“Fuse” Panel
PT Cables
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
Leveraging previous research …



Self-Centering Concepts
- rocking frame/wall systems
- post-tensioned frames
Energy Dissipating Shear Panels
- ductile fiber cementitous composites
- slit steel shear walls
Performance-Based Engineering (PEER/ATC)
- damage & collapse limit states
- economic losses & life-cycle assessment
- simulation tools
Scope

System Design Development
- parametric design studies
- shear panel fuse design and testing
Stanford
- building simulation studies

Subassembly Frame/Fuse Tests
- quasi-static cyclic loading
- PT rocking frame details & response
- panel/frame interaction
- model calibration

NEES - Illinois
Shake Table System Tests
- proof-of-concept
- validation of simulation models
E-Defense
Pivoting Fuse Braced Frames
D
H
Replaceable Fuse
A
B
A
Shear Strains = D/H x A/B
Pivoting Fuse System with Backup MRF

Figure 1a

Elastic restoring force
-
Reduce damage in fuse
Reduce residual
deformations
Provides redundancy
deck/slab
Combined
Framing Plan
Framing Elevation
Moment Resisting Frames
Base Shear
Figure 1a
Pivoting Fuse
MRF
Drift
“Rocking” Braced Frames
Force
No Permanent
Displacement
Gravity load
overturning
resistance
Displacement
Midorikawa, M., Azuhata, T., Ishihara, T. and Wada, A. (2003)
Rocking Braced Frame w/Post Tensioning
Orinda City Offices
Architect: Siegel and Strain Architects
Controlled Rocking Braced Frame with Fuses
Yielding of
Structural Fuse
Structural Fuse
Post-tensioning
(PT) Tendons
PT Cables & Braces
remain elastic
Steel Braced
Frame
A
B
A
Could potentially
employ additional
fuse at base of column
a,f
g
e
b
d
Fuse System
Base Shear
Base Shear
Pretension/Brace System
c
b
c
Fuse Strength
a
PT Strength
d
Eff. Fuse
Stiffness
Drift
Frame Stiffness
g
f
e
Drift
b
Base Shear
Origin-a – frame strain + small
distortions in fuse
a – frame lift off, elongation of PT
b – fuse yield (+)
c – load reversal
d – zero force in fuse
e – fuse yield (-)
f – frame contact
f-g – frame relaxation
g – strain energy left in frame and fuse,
small residual displacement
a
PT
Strength
c
2x Fuse
Strength
d
e
f
PT – Fuse Strength
g
Combined System
Drift
Energy Dissipating Fuse Options


Attributes of Fuse
-
high initial stiffness
large strain capacity
hysteretic energy dissipation
Candidate Fuse Materials &
Designs
-
-
ductile fiber cementitious
composites**
steel panels with slits**
low-yield steel
mixed sandwich panels
Ductile Fiber Reinforced Cemetitious Panels
Tapered Flexural/Shear Links
- Designed for distributed
plasticity
-
Similar in concept to a
“butterfly” link beam
HPFRCC Flexural Panel Tests by Kesner & Billington 2005
Steel Shear Wall with Slits
Hitaka et al., 2004
OpenSees Simulation Model
Nonlinear Truss
Members
Elastic Truss
Members
EPP PostTensioning
Tendons
Uplift
Spring
Cyclic Response
PT Yielding
RDR = 3%
2500
Hardening = 0
PostCap Softening = -0.02
Strength Det. = 0
Unloading Stiff Det. = 0
Accelerated Stiff. Det. = 0
PostCap Strength Det. = 0
2000
1500
Base Shear (kN)
1000
500
0
-500
-1000
-1500
Global3-story
Behavior
Frame
-2000
-2500
-0.06
-0.04
-0.02
0
RDR
0.04
0.06
4% shear strain cap
500
400
0.02
PD Fuse Behavior
300
B
A
DESIGN with R = 8.0
Vd = 0.125W
PT = 1055kN, Vp,fuse = 1687kN
br = 1.0
200
Axial Force (kN)
A
100
0
-100
-200
Pinching
-300
50% residual
-400
-500
-0.08
-0.06
-0.04
-0.02
0
Link Strain
0.02
0.04
0.06
Bilinear vs. Pinching Fuse
3000
2500
2000
2000
1500
1000
Base Shear (kN)
Base Shear (kN)
1000
0
Not
Restoring
-1000
500
0
Restoring
-500
-1000
-1500
-2000
-2000
3-story Frame
-3000
-0.06
Hardening = 0
PostCap Softening = -0.02
Strength Det. = 0
Unloading Stiff Det. = 0
Accelerated Stiff. Det. = 0
PostCap Strength Det. = 0
-0.04
-0.02
0
RDR
0.02
0.04
0.06
-2500
-0.06
3-story Frame
-0.04
-0.02
PT Strength = Fuse Strength
(2PT*A) / (Vp,fuse (A+B)) = 1.0
0
RDR
0.02
0.04
0.06
Maximum Interstory Drift vs. Sa(T1)
2.7%
1.6
2/50 Level
1.4
Inelastic Time History Analyses:
1.2
1.6%
10/50 Level
1
Sa(T ) (g)
1
• Primary EDP: interstory drift
0.8
PT Yielding
0.6
• structural limit states
- column lift-off (rocking)
Unscaled records
0.4
- fuse yielding/damage
- PT yielding
0.2
0
• 20 EQ record pairs, scaled to
increasing intensities
0
0.02
0.04
0.06
0.08
0.1
Maximum IDR
0.12
0.14
0.16
The yellow squares represent the median, 16th and 84th percentile response.
Subassembly Frame Tests (NEES-Illinois)



Test Configuration
- 2/3 scale planar rocking
frame with realistic details
- quasi-static
System Response
- structural details & PT
- various fuse types
- indeterminate shearfuse/frame interaction
Simulation model validation
NEES - Illinois


Large-scale frame
assembly
Validation of dynamic
response and simulation
W 300 (typ)
W 360 (typ)
3 @ 6 m = 18 m
Proof-of-Concept

85 mm slab on
75 mm deck
construction details
3 @ 2.8 m = 8.4 m

re-centering behavior
fuse replacement
Collaboration & Payload
Projects
2.5 m
1m
2.5 m
2@2m=4m
Shake Table Validation Test (E-Defense)
E-Defense Testbed Structure
Section
shaking
direction
Plan View
E-Defense
Collaboration Opportunities

Alternative Fuse Designs

Alternative Rocking Systems

-
rocking column base details
hydraulically actuated self-centering
Industrial Collaboration
-
Steel manufacturers/fabricators
Design practitioners

Related Japanese “Steel Project”

Related US Initiatives
-
PEER Building Benchmarking
ATC 58 & 63
Seismic & Green Design
Rocking Frame
Design Decision Matrix
Life-cycle Financial Assessment
Expected Annual Loss
$80,000
$70,000
$60,000
$50,000
$40,000
$30,000
$20,000
$10,000
$Wood
Steel
w /conventional w /conventional
partitions
partitions
Steel
w /improved
partitions
Annualized Lifecycle Cost
$200,000
$180,000
$160,000
$140,000
$120,000
$100,000
$80,000
$60,000
$40,000
$20,000
$Wood
Steel
w /conventional w /conventional
partitions
partitions
Steel
w /improved
partitions