Seismic Performance of Reinforced Concrete...
Transcript of Seismic Performance of Reinforced Concrete...
Seismic Performance of Seismic Performance of Reinforced Concrete Columns Reinforced Concrete Columns Under Biaxial ExcitationUnder Biaxial Excitation
Tiffany McCarthy
Dept. of Civil & Environmental Engineering
University of Houston
NSF REU Program
August 2007
ContentsContents
IntroductionIntroduction Objectives and ScopeObjectives and Scope ExperimentExperiment ResultsResults AnalysisAnalysis ApplicationsApplications Closing StatementClosing Statement Questions? Questions?
IntroductionIntroduction
Seismic = Earthquake - RelatedSeismic = Earthquake - Related Reinforced = Strengthened/SupportedReinforced = Strengthened/Supported Biaxial = 2 Axes Biaxial = 2 Axes Excitation = Acceleration Excitation = Acceleration 1999 Taiwan Earthquake1999 Taiwan Earthquake
1999 Taiwan Earthquake1999 Taiwan Earthquake
Tungtow BridgeTungtow Bridge
Tungtow Close-UpTungtow Close-Up
Taichung BuildingTaichung Building
Changhwa BuildingChanghwa Building
Objectives and ScopeObjectives and Scope
Subject to biaxial loadsSubject to biaxial loads– Test using more realistic conditionsTest using more realistic conditions
DetermineDetermine– Effect of orientationEffect of orientation– Effect of shear reinforcement ratioEffect of shear reinforcement ratio
Experimental ProgramExperimental Program
Steel ReinforcementSteel Reinforcement
FormworkFormwork
Concrete ColumnConcrete Column
Shake TableShake Table
ResultsResults
Cracking and YieldingCracking and Yielding Failure ModesFailure Modes Ultimate ForcesUltimate Forces Steel YieldingSteel Yielding Energy DissipationEnergy Dissipation Hysteretic ResponseHysteretic Response
SH1 and SH4SH1 and SH4
SH2 and SH5SH2 and SH5
SH3 and SH6SH3 and SH6
Force v. DisplacementForce 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
-2.00E+01
-1.50E+01
-1.00E+01
-5.00E+00
0.00E+00
5.00E+00
1.00E+01
1.50E+01
2.00E+01
Displacement
Fo
rce
SH5 @ 1600 gal
-2.50E+05-2.00E+05
-1.50E+05-1.00E+05-5.00E+040.00E+00
5.00E+041.00E+051.50E+05
2.00E+052.50E+05
-3.00E+01
-2.00E+01
-1.00E+01
0.00E+00 1.00E+01 2.00E+01 3.00E+01
Displacement
Fo
rce
Experimental AnalysisExperimental Analysis
Symmetry significant toSymmetry significant to– StiffnessStiffness– StrengthStrength– DeformationDeformation
Lower Energy Dissipation Than UniaxialLower Energy Dissipation Than Uniaxial Cracking and YieldingCracking and YieldingStiffness decr.Stiffness decr. Stirrup Spacing affects energy dissipation Stirrup Spacing affects energy dissipation
at high excitationat high excitation
ApplicationsApplications
More Reinforcements=More ResistantMore Reinforcements=More Resistant Orientation to Force is KeyOrientation to Force is Key Symmetry MattersSymmetry Matters Reduce Spalling Reduce Spalling
ClosingClosing StatementStatement
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.
Questions?Questions?