SLIDE 1 Seismic Performance of Seismic Performance of Reinforced Concrete Columns Reinforced Concrete Columns Under Biaxial Excitation Under Biaxial Excitation
Tiffany McCarthy
- Dept. of Civil & Environmental Engineering
University of Houston NSF REU Program August 2007
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Contents Contents
Introduction
Introduction
Objectives and Scope
Objectives and Scope
Experiment
Experiment
Results
Results
Analysis
Analysis
Applications
Applications
Closing Statement
Closing Statement
Questions?
Questions?
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Introduction Introduction
Seismic = Earthquake - Related
Seismic = Earthquake - Related
Reinforced = Strengthened/Supported
Reinforced = Strengthened/Supported
Biaxial = 2 Axes
Biaxial = 2 Axes
Excitation = Acceleration
Excitation = Acceleration
1999 Taiwan Earthquake
1999 Taiwan Earthquake
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1999 Taiwan Earthquake 1999 Taiwan Earthquake
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Tungtow Bridge Tungtow Bridge
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Tungtow Close-Up Tungtow Close-Up
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Taichung Building Taichung Building
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Changhwa Building Changhwa Building
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Objectives and Scope Objectives and Scope
Subject to biaxial loads
Subject to biaxial loads
– Test using more realistic conditions Test using more realistic conditions
Determine
Determine
– Effect of orientation Effect of orientation – Effect of shear reinforcement ratio Effect of shear reinforcement ratio
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Experimental Program Experimental Program
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Steel Reinforcement Steel Reinforcement
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Formwork Formwork
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Concrete Column Concrete Column
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Shake Table Shake Table
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Results Results
Cracking and Yielding
Cracking and Yielding
Failure Modes
Failure Modes
Ultimate Forces
Ultimate Forces
Steel Yielding
Steel Yielding
Energy Dissipation
Energy Dissipation
Hysteretic Response
Hysteretic Response
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SH1 and SH4 SH1 and SH4
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SH2 and SH5 SH2 and SH5
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SH3 and SH6 SH3 and SH6
SLIDE 19 Force v. Displacement Force v. Displacement (SH1 [left] and SH5 [right]) (SH1 [left] and SH5 [right])
SH1 @ 1200gal
- 2.00E+05
- 1.50E+05
- 1.00E+05
- 5.00E+04
0.00E+00 5.00E+04 1.00E+05 1.50E+05 2.00E+05 2.50E+05
+01
+01
+01
+00 0.00E+ 00 5.00E+ 00 1.00E+ 01 1.50E+ 01 2.00E+ 01 Displacement Force
SH5 @ 1600 gal
- 2.50E+05
- 2.00E+05
- 1.50E+05
- 1.00E+05
- 5.00E+04
0.00E+00 5.00E+04 1.00E+05 1.50E+05 2.00E+05 2.50E+05
1
1
1 0.00E+00 1.00E+01 2.00E+01 3.00E+01 Displacement Force
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Experimental Analysis Experimental Analysis
Symmetry significant to
Symmetry significant to
– Stiffness Stiffness – Strength Strength – Deformation Deformation
Lower Energy Dissipation Than Uniaxial
Lower Energy Dissipation Than Uniaxial
Cracking and Yielding
Cracking and Yielding Stiffness decr. Stiffness decr.
Stirrup Spacing affects energy dissipation
Stirrup Spacing affects energy dissipation at high excitation at high excitation
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Applications Applications
More Reinforcements=More Resistant
More Reinforcements=More Resistant
Orientation to Force is Key
Orientation to Force is Key
Symmetry Matters
Symmetry Matters
Reduce Spalling
Reduce Spalling
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Closing Closing Statement Statement
Reinforcement and Biaxial Loads are
Reinforcement and Biaxial Loads are significant topics to consider when significant topics to consider when developing better guidelines for concrete developing better guidelines for concrete structures. structures.
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Questions? Questions?
