1. NEESR-SG: Controlled Rocking of Steel-Framed 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

2. 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

3. Objective
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

4. 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

5. Scope System Design Development Subassembly Frame/Fuse Tests
- parametric design studies
- shear panel fuse design and testing
- building simulation studies
Subassembly Frame/Fuse Tests
- quasi-static cyclic loading
- PT rocking frame details & response
- panel/frame interaction
- model calibration
Shake Table System Tests
- proof-of-concept
- validation of simulation models
Stanford
NEES - Illinois
E-Defense

6. Pivoting Fuse Braced FramesH
Replaceable Fuse A B A
Shear Strains = D/H x A/B

7. Pivoting Fuse System with Backup MRF
Elastic restoring force
Reduce damage in fuse
Reduce residual deformations
Provides redundancy
Base Shear
Drift
MRF
Pivoting Fuse
Combined
Moment Resisting Frames

8. “Rocking” Braced Frames
No Permanent Displacement
Force
Gravity load overturning resistance
Displacement
Midorikawa, M., Azuhata, T., Ishihara, T. and Wada, A. (2003)

9. Rocking Braced Frame w/Post Tensioning
Orinda City Offices
Architect: Siegel and Strain Architects

11. PT Cables & Braces remain elastic
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

12. Pretension/Brace System Fuse System
Base Shear
Drift
a,f b c d e g
PT Strength
Frame Stiffness
Fuse System
Base Shear
Drift a b c d e f g
Fuse Strength
Eff. Fuse
Stiffness b c
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
Base Shear
2x Fuse
Strength d a PT
Strength e f
PT – Fuse Strength g
Drift
Combined System

13. 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

14. 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

15. Steel Shear Wall with Slits
Hitaka et al., 2004

16. OpenSees Simulation Model
Nonlinear Truss Members
Elastic Truss Members
EPP Post-Tensioning Tendons
Uplift Spring

17. Cyclic Response DESIGN with R = 8.0 A B PT Yielding RDR = 3%
Global Behavior
PT Yielding
RDR = 3% A B
4% shear strain cap
PD Fuse Behavior
DESIGN with R = 8.0
Vd = 0.125W
PT = 1055kN, Vp,fuse = 1687kN
br = 1.0
Pinching
50% residual

18. Bilinear vs. Pinching Fuse
Not
Restoring
Restoring
PT Strength = Fuse Strength
(2PT*A) / (Vp,fuse (A+B)) = 1.0

19. Maximum Interstory Drift vs. Sa(T1)
2.7%
2/50 Level
Inelastic Time History Analyses:
20 EQ record pairs, scaled to increasing intensities
Primary EDP: interstory drift
structural limit states
- column lift-off (rocking)
fuse yielding/damage
PT yielding
1.6%
10/50 Level
PT Yielding
Unscaled records
The yellow squares represent the median, 16th and 84th percentile response.

20. 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 shear-fuse/frame interaction
Simulation model validation
NEES - Illinois

21. Shake Table Validation Test (E-Defense)
Large-scale frame assembly
Validation of dynamic response and simulation
Proof-of-Concept
construction details
re-centering behavior
fuse replacement
Collaboration & Payload Projects

22. E-Defense Testbed Structure
Section
shaking direction
Plan View
E-Defense

23. 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

24. Design Decision Matrix
Seismic & Green Design
Rocking Frame
Design Decision Matrix

25. Life-cycle Financial Assessment