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CUREe-Kajima Joint Research Program: Phase IV. Seismic Performance Assessment of Flat Plate Floor Systems. 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. Modeling and Performance Issues.
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CUREe-Kajima Joint Research Program: Phase IV Seismic Performance Assessment of Flat Plate Floor Systems 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
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
Column Slab Modeling Approaches • Effective Beam Width - Account for the influence of the concrete cracking (EIeffective)
Column Connection Slab Modeling Approaches • Equivalent Frame Model
Performance Issues - Punching (Hwang)
Performance Issues - Punching (Hwang)
Performance Issues - Punching Continuous bottom reinforcement to prevent collapse (Hwang)
Performance Issues - Gravity Stress Low Vg/Vo High Vg/Vo Lateral Load 1% 2% 4% Drift
Connection Column 1.0 0.04 Slab 0.0 Connection Modeling • Effective Beam Width with Rotational Spring
Vn d Modeling Approaches • Displacement-Based Model with Shear strength degradation Drift derived from Elastic and Inelastic curvature fy fu
Performance Issues - Gravity StressDisplacement-Based Model (Moehle)
Prototype & Test Structure Section A-A • Prototype - Test Structure : 2 Stories, 2 × 2 bays
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)
Shear Reinforcement • Shear Studs (Ghali)
R.C. Flat Plate -Flexural Reinforcement (Test Specimen) • Top Reinforcement • Bottom Reinforcement
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