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PEER 2002 PEER Annual Meeting Limit States and Design Parameters for Flexurally Dominated RC Columns uMarc O. Eberhard uMyles Parrish, Mike Berry uUniversity of Washington

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Objective P[DM|EDP] For a specified deformation, what is the likelihood that a flexurally dominant reinforced column will suffer a particular level of damage?

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Research Approach Identify Key Levels of Damage –Consequences Identify Promising Deformation Parameters –Accuracy, Generality, Reproducibility Assemble Database of Test Results Correlate Damage with Deformation Parameters

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Typical Progression of Damage Onset of Spalling Onset of Bar Buckling Loss of Axial Load

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Demand Parameters Peak Deformation Drift Ratio Plastic Rotation Displacement Ductility Maximum Compressive Strain Maximum Tensile Strain Deformation Controlled

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PEER 2002 PEER Annual Meeting Database of Test Results

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Typical F Properties Table Test Results References Properties Table Test Results References Properties Table Test Results References Properties Table Test Results References Spiral-Reinforced Columns (149 tests) Rectangular Columns (204 tests) Columns with Splices (7 tests) Retrofitted Columns (11 tests) PEER Column Performance Database

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Typical Test Configuration

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Typical Force-Displacement History Nelson and Price, 2000 (P3) Displacement (in.) Applied Force (kips)

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Displacement (in.) Applied Force (kips) Nelson and Price, 2000 (P3) SP BB AX

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PEER 2002 PEER Annual Meeting Correlate Deformation Measures and Observed Damage: Onset of Spalling

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Drift Ratio at Onset of Spalling

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Concrete Strain at Onset of Spalling

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Why So Much Scatter?? Observer Subjectivity Discrete Levels of Imposed Deformation Model Inaccuracy –complicated phenomena –effects of cycling –force-deformation response

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(P/f'cAg < 0.35) K meas /K calc HOGNKPMANDSAAT 0 < L/D < 3 3 < L/D < 8 MEAN

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(P/f'cAg < 0.35) K meas /K calc COV HOGNKPMANDSAAT

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PEER 2002 PEER Annual Meeting Correlate Deformation Measures and Observed Damage: Onset of Bar Buckling

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Drift Ratio at Onset Bar Buckling Rectangular Reinforced

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Drift Ratio at Onset Bar Buckling Rectangular Reinforced

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Drift Ratio at Onset Bar Buckling Rectangular Reinforced DR buckle (%)= 2.5 (1-P/A g f’ c )(1+8 s f y /f’ c)

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Strain at Onset of Bar Buckling

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buckle = s f y /f’ c

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PEER 2002 PEER Annual Meeting Application

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Probability of Bar Buckling

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Conclusions Database provides the information needed to systematically evaluate the accuracy of force-displacement and damage models. For a given level of deformation, one can estimate the likelihood of reaching a particular level of damage.

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PEER 2002 PEER Annual Meeting Questions?

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