Self-Centering Seismic-Resistant Steel Frame ... - Lehigh …€¦ · Self-Centering...
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Self-Centering Seismic-Resistant Steel Frame Systems: Overview of Past and Current Research Richard Sause and James M. Ricles ATLSS Center, Dept. of Civil and Envir. Engineering, Lehigh University Maria E. Moreyra Garlock and Erik VanMarcke Dept. of Civil and Envir. Engineering, Princeton University Judy Liu Dept. of Civil Engineering, Purdue University Li-Shiuan Peh Dept. of Electrical Engineering, Princeton University Acknowledgements • Sponsors of Past and Current Research: • National Science Foundation. • Lehigh University and ATLSS Center. • Precast-Prestressed Concrete Institute (PCI). • Pennsylvania Infrastructure Technology Alliance. • Professor Emeritus Le-Wu Lu • Professor Stephen Pessiki • Former Ph.D. Students Conducting to Past Research: • Y.C. Kurama • M. El-Sheikh • F.J. Perez • S.-W. Peng • M.M. Garlock • P. Rojas • C.-Y. Seo
Transcript of Self-Centering Seismic-Resistant Steel Frame ... - Lehigh …€¦ · Self-Centering...
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Self-Centering Seismic-Resistant Steel Frame Systems: Overview
of Past and Current ResearchRichard Sause and James M. Ricles
ATLSS Center, Dept. of Civil and Envir. Engineering, Lehigh University
Maria E. Moreyra Garlock and Erik VanMarckeDept. of Civil and Envir. Engineering, Princeton University
Judy LiuDept. of Civil Engineering, Purdue University
Li-Shiuan PehDept. of Electrical Engineering, Princeton University
Acknowledgements• Sponsors of Past and Current Research:
• National Science Foundation. • Lehigh University and ATLSS Center.• Precast-Prestressed Concrete Institute (PCI).• Pennsylvania Infrastructure Technology Alliance.
• Professor Emeritus Le-Wu Lu• Professor Stephen Pessiki• Former Ph.D. Students Conducting to Past Research:
• Y.C. Kurama• M. El-Sheikh• F.J. Perez• S.-W. Peng• M.M. Garlock• P. Rojas• C.-Y. Seo
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ATLSS CenterLehigh University
Self-Centering (SC) Seismic-Resistant Structural Systems
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Lateral Drift (%)
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• Unbonded post-tensioned precast walls:– With and without energy dissipation elements
• Unbonded post-tensioned precast moment-resisting frames:– Without energy dissipation elements
• Steel moment resisting frames with post-tensioned connections:– With energy dissipation elements
Previously Studied SC Seismic-Resistant Structural Systems
Unbonded post-tensioned (PT) precast walls
SC Seismic-Resistant Structural Systems
Unbonded PT precastwalls with ductile
vertical joint connectors
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Unbonded post-tensioned precast
frames
SC Seismic-Resistant Structural Systems
Fiber Reinforced Grout
Post-Tensioned Unbonded Strands
• Steel moment-resisting frames (MRFs) with post-tensioned connections: – with top and
bottom seat angles
– with friction devices
SC Earthquake-Resistant Structural Systems
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• Structural systems are post-tensionedto pre-compress joints between discrete structural members
• Gap opening at joints at selected seismic load levels provides softening of lateral force-drift behavior without damage to members
• PT forces close joints and permanent lateral drift is avoided
SC Seismic-Resistant Structural System Concepts
M
SC Seismic-Resistant Structural System Features
1. Economy, since structural member size and complexity in SC systems are similar to conventional seismic-resistant systems
2. Reduced damage, since SC systems can be designed to resist design basis earthquake without significant damage
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SC Seismic-Resistant Structural System Features
3. Initial lateral stiffness is similar to that of conventional seismic-resistant systems
4. Lateral force-drift behavior softens:– to control force demands under seismic load
– due to gap opening at selected joints
– without significant inelastic deformation and damage to main structural members, avoiding residual drift
SC Seismic-Resistant Structural System Features
5. Ductility capacity:– can be quite large– is not fully controlled by material ductility– can be enhanced by changes in post-
tensioning
6. Energy dissipation:– from energy dissipation elements– not from damage to main structural members
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Lateral Displacement - ∆ (mm)
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Stiffness with welded connection
Initial Stiffness Is Similar to Stiffness of Conventional Systems
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PT Steel MRF
MRF subassembly with post-tensioned connections
Base Shear
Lateral Drift
failure
effectivelinear limit
PT yielding
decompression
Lateral Force-Drift Behavior Softens to Control Force Demands
• Softening controls acceleration and force demands under seismic loading
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Steel MRF subassembly with post-tensioned connections and angles at 3% drift
Lateral Force-Drift Behavior Softens Due to Gap Opening
Lateral Force-Drift Behavior Softens Without Inelastic Deformation
• Conventional system softens by inelastic deformation which damages main structural members and results in residual drift
• Self-centering system softens by gap opening and reduced contact area at joints
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Displacement, ∆ (in)
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Welded Connection
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Unbonded post-tensioned precastwall at 3rd cycle to 3% drift
Lateral Force-Drift Behavior Softens Due to Gap Opening
Unbonded post-tensioned precastwall after 3rd cycle to 3% drift
Lateral Force-Drift Behavior Softens Without Inelastic Deformation,
Avoiding Residual Drift
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Lateral Drift (%)
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T3 (Ap = 7.50 in.2)T5 (Ap = 3.75 in.2)
fpi/fpu = const.
Ductility Capacity
• Can be quite large
• Is not fully controlled by material ductility
• Can be enhanced by changes in post-tensioning
Energy Dissipation from Energy Dissipation Elements
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Lateral Displacement, ∆ [mm]
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Specimen PC2L6x6x5/16, g/t = 4
Specimen PC4L8x8x5/8, g/t = 4
Steel MRF subassemblies with post-tensioned connections with different size angles
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Steel MRF
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Displacement, ∆ [mm]
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Energy Dissipation Not from Damage to Main Structural Members
Steel MRF subassemblies with post-tensioned connections with no angles
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Steel MRF
Relative Energy Dissipation of SC Systems
β : Relative energy dissipation capacity
β = 0 % β = 12.5 %* β = 25 % β = 50 %
( )100 %Area of yellow xArea of blue
β =
* Minimum per ACI T1.1-01.
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Effect of Energy Dissipation on Ductility Demand
µ%
T0
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R = 4
fs damping
BE-2 (0%)SC12.5-2SC25-2SC50-2Conventional
Energy Dissipation
• SC systems should have energy dissipation elements
• These elements may be damaged and replaced
• Behavior of these elements will control system energy dissipation, with no significant energy dissipation from main structural members
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Summary of SC Seismic-Resistant Structural System Features
1. Economy, since structural member size and complexity in SC systems are similar to conventional seismic-resistant systems
2. Reduced damage, since SC systems can be designed to resist design basis earthquake without significant damage
Summary of SC Seismic-Resistant Structural System Features
3. Initial lateral stiffness is similar to that of conventional seismic-resistant systems
4. Lateral force-drift behavior softens:– to control force demands under seismic load
– due to gap opening at selected joints
– without significant inelastic deformation and damage to main structural members, avoiding residual drift
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Summary of SC Seismic-Resistant Structural System Features
5. Ductility capacity:– can be quite large– is not fully controlled by material ductility– can be enhanced by changes in post-
tensioning
6. Energy dissipation:– from energy dissipation elements– not from damage to main structural members
Summary of Past Research
• Studies of different SC seismic-resistant structural systems have been conducted
• Studies have identified attractive features summarized earlier
• Seismic performance can exceed that of conventional systems (reduced residual drift, reduced damage)
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NEESR SC Steel Frame Systems Project Goals
• Overall: self-centering steel systems that are constructible, economical, and structurally damage-free under design earthquake
• Specific:– fundamental knowledge of seismic behavior of
SC-MRF systems and SC-CBF systems– integrated design, analysis, and experimental
research using NEES facilities– performance-based, reliability-based seismic
design procedures
Research Needs for SC Moment Resisting Frames (SC-MRFs)
• Interaction between SC-MRFs and floor diaphragms• Improved energy dissipation elements for SC-MRF
connections• SC column base connections for SC-MRFs• Parametric studies of SC-MRFs for various buildings• Design procedures for SC-MRFs with clear
performance objectives and reliability concepts• Large-scale tests on SC-MRF systems, including floor
diaphragms, with realistic seismic input
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Research Needs for SC Concentrically Braced Frames (SC-CBFs)
• PT systems and connection concepts for SC-CBFs• Analytical models for SC-CBFs• Initial laboratory studies of SC-CBFs• Energy dissipation elements for SC-CBFs• SC column base connections for SC-MRFs• Design procedures for SC-CBFs with clear
performance objectives and reliability concepts• Large-scale tests on SC-CBF systems, including floor
diaphragms, with realistic seismic input
Research Tasks1. Develop reliability-based seismic design and assessment procedures2. Develop SC-CBF systems3. Further develop SC-MRF systems4. Develop energy dissipation elements for SC-MRFs and SC-CBFs5. Develop sensor networks for damage monitoring and integrity
assessment6. Design prototype buildings7. Perform nonlinear analyses of prototype buildings8. Conduct large-scale laboratory tests of SC-MRFs and SC-CBFs9. Collaborate on 3-D large-scale laboratory experiments on SC-MRF
and SC-CBF systems
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Task 1: Develop Design Procedures VanMarcke, Garlock
Task 3: Develop SC-MRF SystemsGarlock, Liu
Task 5: Develop Sensor Networks Peh, VanMarcke
Task 2: Develop SC-CBF SystemsSause, Ricles
Task 4: Develop Energy
Dissipation ElementsSause, Ricles
Task 6: Design Prototype Frames
Garlock, Liu
Task 7: Perform Nonlinear Analyses of SC-MRF and SC-CBFGarlock, VanMarcke
Task 8: Conduct Large-Scale Simulations
Ricles, Sause
Task 9: Conduct 3-D Large-Scale
SimulationsTsai, Sause
Subtasks 3.6, 3.13: Conduct Experimental
Evaluations
Subtasks 2.5, 3.3, 3.10: Develop Finite
Element Models
Subtask 2.9: Conduct
Experimental Evaluations
NCREE Lehigh University Princeton University Purdue University
Prot
otyp
e Fr
ames
Preliminary Procedures
AnalyticalModels
Subtask 4.4: Conduct ED Element
Tests
Subtask 4.3: Develop ED Element
Models
Feasible ED ElementsED
Behavior
ED Models
Prototype Frame ResponsePrototype Frame
Performance
Prototype Frame Performance
Test Frame Behavior
Test Frame BehaviorSC
-CBF
Con
figur
atio
ns
Com
pone
nt B
ehav
ior
SC-C
BF C
onfig
urat
ions
SC-CBF Configurations
Prototype Frames
SC-CBF
SC-M
RFCo
nfig
urat
ions
SC-MRF
SC-M
RF C
onfig
urat
ions
Com
pone
nt B
ehav
iorSe
nsor
N
etw
orks
Sens
or
Net
wor
ks
ED Models
Test
Fra
me
Beha
vior
Fundamental and Practical Knowledge of
SC Steel Frame
Systems
Reliability-Based Design Procedures and Criteria for SC Steel
Frame Systems
Sensor Network
Technology for Monitoring
SC Steel Frame
Systems
Archived Project Data
and Metadata
SC Steel Frame
Systems Course
Students and Practitioners
Educated about SC Steel
Frame Systems
Project Outcomes: Research Education
Task 1: Develop Design Procedures VanMarcke, Garlock
Task 3: Develop SC-MRF SystemsGarlock, Liu
Task 5: Develop Sensor Networks Peh, VanMarcke
Task 2: Develop SC-CBF SystemsSause, Ricles
Task 4: Develop Energy
Dissipation ElementsSause, Ricles
Task 6: Design Prototype Frames
Garlock, Liu
Task 7: Perform Nonlinear Analyses of SC-MRF and SC-CBFGarlock, VanMarcke
Task 8: Conduct Large-Scale Simulations
Ricles, Sause
Task 9: Conduct 3-D Large-Scale
SimulationsTsai, Sause
Subtasks 3.6, 3.13: Conduct Experimental
Evaluations
Subtasks 2.5, 3.3, 3.10: Develop Finite
Element Models
Subtask 2.9: Conduct
Experimental Evaluations
NCREE Lehigh University Princeton University Purdue University
Prot
otyp
e Fr
ames
Preliminary Procedures
AnalyticalModels
Subtask 4.4: Conduct ED Element
Tests
Subtask 4.3: Develop ED Element
Models
Feasible ED ElementsED
Behavior
ED Models
Prototype Frame ResponsePrototype Frame
Performance
Prototype Frame Performance
Test Frame Behavior
Test Frame BehaviorSC
-CBF
Con
figur
atio
ns
Com
pone
nt B
ehav
ior
SC-C
BF C
onfig
urat
ions
SC-CBF Configurations
Prototype Frames
SC-CBF
SC-M
RFCo
nfig
urat
ions
SC-MRF
SC-M
RF C
onfig
urat
ions
Com
pone
nt B
ehav
iorSe
nsor
N
etw
orks
Sens
or
Net
wor
ks
ED Models
Test
Fra
me
Beha
vior
Fundamental and Practical Knowledge of
SC Steel Frame
Systems
Reliability-Based Design Procedures and Criteria for SC Steel
Frame Systems
Sensor Network
Technology for Monitoring
SC Steel Frame
Systems
Archived Project Data
and Metadata
SC Steel Frame
Systems Course
Students and Practitioners
Educated about SC Steel
Frame Systems
Project Outcomes: Research Education
Fundamental and Practical Knowledge of
SC Steel Frame
Systems
Reliability-Based Design Procedures and Criteria for SC Steel
Frame Systems
Sensor Network
Technology for Monitoring
SC Steel Frame
Systems
Archived Project Data
and Metadata
SC Steel Frame
Systems Course
Students and Practitioners
Educated about SC Steel
Frame Systems
Project Outcomes: Research Education
Research Tasks
Self-Centering Seismic-Resistant Steel Frame Systems: Overview
of Past and Current Research
Thank You
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