1. NEESR-SG: Controlled Rocking of Steel-Framed Buildings with Replaceable Energy Dissipating Fuses Gregory G. Deierlein, Sarah Billington, Helmut Krawinkler, Xiang Ma, Alejandro Pena, Eric Borchers, Stanford University Jerome F. Hajjar, Matthew Eatherton, Noel Vivar, Kerry Hall, University of IL Mitsumasa Midorikawa, Hokkaido University Toko Hitaka, Kyoto University David 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.

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. 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

4. Corner of frame is allowed to uplift. Fuses absorb seismic energy Post-tensioning brings the structure back to center. Result is a building where the structural damage is concentrated in replaceable fuses with little or no residual drift Controlled-Rocking System

5. 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

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

7. Base Shear Drift a bc d f g Combined System Origin-a – frame strain + small distortions in fuse a – frame lift off, elongation of PT b – fuse yield (+) c – load reversal (PT yields if continued) 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 Fuse System Base Shear Drift a bc d efg Fuse Strength Eff. Fuse Stiffness PT Strength PT – Fuse Strength Pretension/Brace System Base Shear Drift a,f b c d e g PT Strength Frame Stiffness e 2x Fuse Strength

8. Shear Fuse Testing - Stanford 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

9. Fuse Configurations B L b thickness t h a R56-10BR “R”: Rectangular “B”: Butterfly “BR”: Buckling-restrained “W”: Welded L/tb/t Notation: Rectangular link: b/t and L/t Butterfly link: b/a Welded endBuckling-restrained

10. Test Matrix IDLbtanL/tb/tL/ba/b Test Sequence R36-1292.880.252.8873611.53.111 R40-10102.380.252.3813409.54.212 R56-10142.380.252.3813569.55.913 R56-10BR142.380.252.3813569.55.914 B36-1092.500.251.0063610.03.60.45 B37-06142.250.3750.757376.06.20.339 B56-09142.250.250.757569.06.20.3310 B14-02142.2510.753142.36.20.3311 B36-10W92.500.251.0063610.03.60.46 R36-10W92.500.252.5063610.03.617 B18-07W93.500.51.403187.02.60.48 h = 20” Dimensions of Specimens (Unit: inch)

11. Testing Results: Rectangular links R36-12 R40-10 R56-10 R56-10BR

12. Testing Results: Load-Deformation R36-12 R40-10 R56-10 R56-10BR

13. Testing Results: Butterfly links B36-10 B56-09 B37-06B14-02

14. Testing Results: Load-deformation B36-10 B56-09 B37-06B14-02

15. Similar Deformation Mode ABAQUS Modeling of Fuse

16. Case Review: Butterfly panel B56-09

17. Beam Behavior

18. Beam Lateral-torsional Buckling

19. Severe Buckling, End of Beam Behavior

20. Pinned Column Behavior

21. Column Buckling in Compression Load

22. Mechanism

23. Fracture, End of Test

24. Equations for Butterfly Panel Design Yield and plastic strength Stiffness (load/displacement) Yield displacement Yield shear drift

25. Comparison with Test Results ID CalculationTestComparison kVyVy VpVp ktkt V yt V ut k t /kV yt /V y V ut /V p B36-10412.4417.7327.14251.8616.3842.160.610.921.55 B56-0993.379.4115.8885.098.6021.570.91 1.36 B37-06140.0613.2822.40113.4410.5936.400.810.801.62 B14-02160.0612.5021.10144.3414.4344.320.901.152.10 Stiffness agrees well except for case B36-10. This panel has end zones whose deformation is not considered in equations Yield strength prediction in good agreement. Generally, prediction is slightly higher than test results Strength increase factor varies from 1.3 to 2.1 Units: kip, inch V ut : maximum load from test

26. Prototype Structure

27. 1.A/B ratio – geometry of frame 2.Overturning Ratio (OT) – ratio of resisting moment to design overturning moment. OT=1.0 corresponds to R=8.0, OT=1.5 means R=5.3 3.Self-Centering Ratio (SC) – ratio of restoring moment to restoring resistance. 4.Initial P/T stress 5.Frame Stiffness 6.Fuse type including degradation Parametric Study – Parameters Studied

28. UIUC Half Scale Tests

30. Elevation of Post Tensioning Column Base

31. Test Matrix Test ID Dim “B” 1 A/B Ratio OT Ratio SC Ratio Num. of 0.5” P/T Strands Initial P/T Stress 2 and Force Fuse Type and Fuse Strength Fuse ConfigurationTesting Protocol A12.06’2.51.0 (R=8) 0.880.287 Fu (94.8 kips) Steel Butterfly 1 (84.7 kips) Six – 1/4” thick fuses 3F-025-AB2.5-OT1.0 Quasi- Static A22.06’2.51.0 (R=8) 0.880.287 Fu (94.8 kips) Steel Butterfly 2 (84.7 kips) Two – 5/8” thick Fuses 1F-0625-AB2.5-OT1.0 Quasi- Static A32.06’2.51.5 (R=8) 0.880.430 Fu (142.3 kips) Steel Butterfly 3 (84.7 kips) Two – 5/8” thick Fuses 1F-0625-AB2.5-OT1.5 Hybrid Simu- lation 3 A42.06’2.51.5 (R= 5.3) 0.880.430 Fu (142.3 kips) Steel Butterfly 3 (127.0 kips) Two – 1” thick Fuses 1F-1-AB2.5-OT1.5 Quasi- Static B13.06’1.691.0 (R=8) 0.870.328 Fu (94.8 kips) Steel Butterfly 4 (75.4 kips) Six – 1/4” thick fuses 3F-025-AB1.69-OT1.0 Quasi- Static B23.06’1.691.0 (R=8) 0.870.328 Fu (94.8 kips) Steel Butterfly 5 (75.4 kips) Two – 5/8” thick Fuses 1F-0625-AB1.69- OT1.0 Quasi- Static B33.06’1.691.0 (R=8) 0.870.328 Fu (94.8 kips) Steel Butterfly 4a (75.4 kips) Six – 1/4” thick fuses 3F-025-AB1.69-OT1.0 Hybrid Simu- lation 3 B43.06’1.691.5 (R= 5.3) 0.870.492 Fu (142.3 kips) Steel Butterfly 6 (113.2 kips) Two – 1” thick Fuses 1F-1-AB1.69-OT1.5 Quasi- Static

32. Test FrameTest-bed Unit

33. Basic Layout Test Bed Units Test Frame Shaking Direction Shaking Table Linear Sliders

34. Connection Between Test Frame & Unit Connection Beam Load Cell Pantograph Test Frame Test Bed Unit

35. 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

36. E-Defense Rocking Frame Configuration

37. Chicago, Illinois Urbana- Champaign, Illinois Thank you