Seismic Performance Assessment of Flat Plate Floor Systems

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Seismic Performance Assessment of Flat Plate
Floor Systems
CUREe-Kajima Joint Research Program Phase IV

• John W. Wallace, Ph.D., P.E.
• Thomas Hyun-Koo Kang, Ph.D. Student
• Department of Civil and Environmental Engineering
• University of California, Los Angeles

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Modeling and Performance Issues

• Lateral stiffness and ductility of the
  column-slab system
• Shear Reinforcement
• Conventional Shear Stirrups
• Shear Studs
• Punching Failures
• Strength and deformation capacity
• Stiffness degradation in the connection region
• progessive collapse prevention

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Modeling Approaches

• Effective Beam Width

- Account for the influence of the concrete
cracking (EIeffective)
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Modeling Approaches

• Equivalent Frame Model

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Performance Issues - Punching
(Hwang)
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Performance Issues - Punching
(Hwang)
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Performance Issues - Punching
Continuous bottom reinforcement to prevent
collapse
(Hwang)
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Performance Issues - Gravity Stress
Low Vg/Vo
High Vg/Vo
Lateral Load
1 2 4
Drift
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Connection Modeling

• Effective Beam Width with Rotational Spring

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Modeling Approaches

• Displacement-Based Model with Shear strength
  degradation

Drift derived from Elastic and Inelastic
curvature
fy
fu
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Performance Issues - Gravity StressDisplacement-B
ased Model (Moehle)
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Prototype Test Structure
Section A-A

• Prototype

- Test Structure 2 Stories, 2 2 bays
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Earthquake Simulator - Shake Table

• Shake Table Test

• Scale , Span-Depth Ratio
• - R.C. Flat Plate 9/20 , 1/30
• - Post-Tensioned Flat Plate 1/3 , 1/33

(Shahrooz)
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Shear Reinforcement

• Shear Studs

(Ghali)
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R.C. Flat Plate - Flexural Reinforcement (Test
Specimen)

• Top Reinforcement

• Bottom Reinforcement

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P.T. flat Plate - Flexural Reinforcement(Test
Specimen)

• Tendon Arrangement

- Scale 1/3 - Span-depth ratio 1/33 - Tendon
3/8 in diameter seven-wire strands
(Grade 270) - Bonded Reinforcement 3 3 in
each direction