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Non-Linear Analysis & Performance-based Design: Current State-of-practice in Earthquake EngineeringShort SeminarUniversitas Tarumanagara, Jakarta 6 February 2004Leonardi KawidjajaSenior AssociatePT Rekacipta KinematikaConsulting Engineerswww.kinematika.com
Current Global Trends• More complex structures• Higher performance requirements• More complete earthquake records• Better understanding of structural non-linear
behaviour• Lessons learned from major earthquakes• Advanced earthquake protection technology• Advanced material technology• Public awareness on earthquake hazard
Earthquake Engineering in 21st Century
towards “Performance-based” Design
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Earthquake Engineering in 21st Century
Traditional Design• Force-based• Force Reduction Factor (R)• Linear Analysis• “Extrapolated” Structural Behaviour
Earthquake Engineering in 21st Century
Nature is Non Linear
Traditional Design• Force-based• Force Reduction Factor (R)• Linear Analysis• “Extrapolated” Structural Behaviour
Modern Design Methodology• Displacement-based• Performance Design• Non-linear Analysis• “Real” Structural Behaviour
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Earthquake Engineering in 21st Century
Modern Design Methodology• Displacement-based• Performance Design• Non-linear Analysis• “Real” Structural Behaviour
Traditional Design• Force-based• Force Reduction Factor (R)• Linear Analysis• “Extrapolated” Structural Behaviour
Performance-based Design
• Performance Objectives– Earthquake Risk– Acceptable Damage
• Code Provisions– SEAOC “Blue Book”– ATC-40– FEMA 356
• Japanese Practice• Acceptance Criteria
– Plastic deformation– Drift ratio
CPLS
IO
OP
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Non-Linear Analysis
• Analysis Procedure:– Non-linear Static:
pushover analysis– Non-linear Dynamic:
time history analysis• Geometric Non-linearity:
– P-delta effect– tension structures
• Material Non-linearity:– Elastoplastic material– Viscoelastic material– Hysteretic damping
Non-Linear Analysis: Static Pushover
Pushover Forces
Plastic Hinges Formation
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Non-Linear Analysis: Static Pushover
Performance Point :• Approximate displacement of the
building in the desired Performance Objective
• Bilinear Coefficient Method– Graphical & Analytical– δT = C0 C1 C2 C3 (4π2)/(Te
2) Sa W
• ADRS Method– Acceleration-Displacement
Response Spectrum– Analytical
Performance Point
Non-Linear Analysis: Static Pushover
Acceptance Criteria?• Inelastic Deformation
– plastic hinge rotation, plastic strain, etc• Total Deformation:
– drift, total strain, etc
@ Performance Point !
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Non-Linear Analysis: Dynamic Time History
Earthquake time-history record
Plastic hinge formation in “real time”
Non-Linear Analysis: Dynamic Time History
Scaled Response Spectra
Peak Ground Acceleration
Scaled Time History
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Non-Linear Analysis: Dynamic Time History
Acceptance Criteria?• Inelastic Deformation
– plastic hinge rotation, plastic strain, etc• Total Deformation:
– drift, total strain, etc
Analysis Methodology
Static Pushover• Less complex• Similar to traditional method• “Pushover” force• No dynamic behaviour• No energy dissipation• No cyclic stiffness
degradation• Conventional structure
Dynamic Time History• Very complex• Numerical simulation• Real earthquake input• Non-linear dynamic behaviour• Hysteretic energy dissipation• Cyclic strength & stiffness
degradation• Any structure
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Non-Linear Analysis ToolsStatic Pushover Analysis• DRAIN 2DX• RAM X-Linea• SAP2000 NL-Push• etcDynamic Time History Analysis• SAP2000 NL-Push• LS-DYNA• ADINA• ABAQUS• LUSAS• IDARC• etc
SAP2000 NL-PUSH
• Non-Linear Static & Dynamic Implicit FEA Code• By Computer & Structures Inc (CSI), CA• Features:
– Integrated ATC-40 Static Pushover protocol– Non-linear Dynamic Time History analysis– Non-linear frame elements for Static
Pushover– Non-linear “link” elements for Time History
• Platform: Windows • Practical Seismic Analysis & Design
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SAP2000 NL-PUSH
Ford Otosan Golcük, Turkey: RC Moment FrameNon-Linear Static Pushover Analysis
SAP2000 NL-PUSH
Maison Hermés, Tokyo: stepping columns with viscoelastic dampersNon-Linear Dynamic Time History Analysis
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LS-DYNA
• Non-Linear DYNAMIC Time-Domain Explicit FEA Code
• Source code by Livermore Software, CA• Impact, Metal Forming, Blast, Vibration, Earthquake,
Wave, Wind & other dynamic loadings• Platform: Unix (64-bit) or WindowsNT (32-bit)• “Heavy-duty” dynamic analysis for complex structures
Non
-line
ar
Sol
ver
LS-DYNA
Gra
phic
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re-p
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ssor
s
Gra
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ost-p
roce
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D3PLOTPRIMER
THISOASYS SHELL
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LS-DYNA
Maison Hermés, Tokyo: stepping columns with viscoelastic dampersNon-Linear Dynamic Time History Analysis
LS-DYNA
Maison Hermés, Tokyo: stepping columns with viscoelastic dampersNon-Linear “Pseudo-Static” Pushover Analysis
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LS-DYNA: Performance Verification
Menara Jakarta, Indonesia• 588 m Telecommunications Tower• To be the tallest free standing structure in
the world• Construction halted in 1997• Long period• RC mega-columns & spandrels• RC perforated shear walls• Response to long period ground motion
from strong distant earthquake
LS-DYNA: Performance Verification
• 2000 yrs EQ• 100 sec EQ• Seismic Beam• Elastoplastic Shell
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LS-DYNA: Performance Based Design
Toyota Football Stadium, Toyota, Japan• 40,000 seat stadium• Retractable Roof• Kisho Kurokawa Architects• Cable-stayed Grand Stand Roof• Unbonded Braced Frame• 2-level performance design:
– Level 1: pgv = 25 kine– Level 2: pgv = 50 kine
• Hyotei Special Building Permit Process
LS-DYNA: Performance Based Design
• Tension Cables• Cable Pretension• Unbonded Brace• Steel Moment
Frame• Inelastic Spring• Seismic Beam
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LS-DYNA: Design of Seismic Isolation
San Francisco Civic Center Sculpture, San Francisco, CA• 13 m tall• Light-weight tension wire “wraps”• Slender compression column• UBC Zone 4, EPA = 0.4g• Friction Pendulum base isolation
LS-DYNA: Design of Seismic Isolation
• Wire pretension• Base isolation• Inelastic Springs
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LS-DYNA: Dynamic Soil-Structure Interaction Analysis
Core Pacific City, Taipei, Taiwan• Multi-storey commercial
complex• Multi-level basement• Piled foundation• Soil-pile interaction
modelling• Reduced pile design!
LS-DYNA: Dynamic Soil-Structure Interaction Analysis
• Rock ground motion
• Hysteretic soil model
• Seismic beam piles
• Seismic beam frames
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LS-DYNA: Dynamic Soil-Structure Interaction Analysis
• Rock ground motion
• Hysteretic soil model
• Seismic beam piles
• Seismic beam frames
LS-DYNA: Pounding Analysis
P&G Sanipak Production Building, Gebze, Turkey
• Single-storey cantilever column building• Near fault strong ground motion• Six separate compartments• Insufficient gap to avoid pounding• Mid-level and Roof-level pounding
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LS-DYNA: Pounding Analysis
• Gap element: compression only spring
• Seismic beam• Elastoplastic shell
LS-DYNA: Pounding Analysis
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LS-DYNA: Rocking AnalysisSpent Nuclear Fuel Flask Storage Platform
• Dynamic overturning• Gravity stabilised
structures• Two overturning
bodies:– Fuel Flask– Platform
• Contact surfaces
LS-DYNA: Rocking AnalysisSpent Nuclear Fuel Flask Storage Platform
• Dynamic overturning• Gravity stabilised
structures• Two overturning
bodies:– Fuel Flask– Platform
• Contact surfaces
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LS-DYNA: Virtual Testing
P&G Takasaki Building 51, Takasaki, Japan
• Seven-storey steel frame building• FEMA 273 seismic retrofit• Latticed beams & columns• Numerical simulations of cyclic and
monotonic testing of latticed beam & column sub-assemblies
• Ductility parameters
LS-DYNA: Virtual Testing
• Repeated incremental cyclic loading
• Bilinear elastoplastic shell elements
• Non-linear springs for rivet shear & tension
• Contact surface
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CURRENT STATE-OF-PRACTICE
• Not yet required by standard design codes• ALTERNATIVE design methodology• High-Performance or High-Tech structures• Evaluation of Existing Structures• Risk Assessment• Expensive: manhours & software• Limited knowledge on non linear concepts• Limited skills on non linear methodologies
Performance-based Design Exotica
THE FUTURE
• Performance-Based Design Codes• Taller, Bigger, Crooker, Better • “Active” Seismic Protection Device• Advanced Material Technology• Advanced Structural Optimisation• Powerful computing power• Lower computing cost• Advanced, affordable analysis codes• Man (woman) behind the machines• Designer or Operator?
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© 2004
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