SEISMIC PERFORMANCE OF CIRCULAR CONCRETE FILLED STEEL TUBE COLUMNS FOR ACCELERATED BRIDGE CONSTRUCTION by Catherine Tucker A thesis submitted to the faculty of The University of Utah in partial fulfillment of the requirements for the degree of Master of Science Department of Civil and Environmental Engineering The University of Utah August 2014 Copyright © Catherine Tucker 2014 All Rights Reserved The University of Utah Graduate School STATEMENT OF THESIS APPROVAL The thesis of Catherine Tucker has been approved by the following supervisory committee members: Luis Ibarra , Chair May 9, 2014 Date Approved Chris Pantelides , Member May 9, 2014 Date Approved Amanda Bordelon , Member May 9, 2014 Date Approved and by Michael Barber , Chair/Dean of the Department/College/School of Civil and Environmental Engineering and by David B. Kieda, Dean of The Graduate School. ABSTRACT This study evaluates the seismic performance of circular concrete filled tube (CCFT) columns in accelerated bridge construction (ABC) projects. CCFT components are considered of interest for bridges subjected to seismic forces due to their efficient structural behavior under combined axial and bending loads: lateral stiffness of the steel tube is increased by the concrete and concrete confinement is provided by the steel tube. This research addresses the ability of CCFT columns to perform adequately under gravitational and seismic loading before the concrete reaches its design strength. A reduced seismic hazard that accounts for this temporal condition is also implemented. Performance evaluation is based on the probability of failure of the CCFT column. For this research, a Caltrans bridge used in previous Pacific Earthquake Engineering Research Center (PEER) studies is adopted. The performance of a proposed CCFT column was compared to the original circular reinforced concrete (RC) column. Numerical analyses using concentrated plasticity models in OpenSees were used for this evaluation. Experimental data were used to calibrate the deteriorating response of CCFT columns in OpenSees. The analytical model predicts the CCFT column’s behavior under monotonic, static cyclic, and dynamic (seismic) loading. Then, the model was adapted to consider the effects of partial concrete compressive strength on the column behavior. The study accounts for temporary conditions, such as concrete compressive strength lower than the design value, and reduced seismic loads. The results indicate that CCFT columns with partial design concrete compressive strength can be used for ABC because the relatively low decrease in strength is offset by the reduced seismic loads for this temporal condition. iv dedicated to Elisabeth and Peter TABLE OF CONTENTS ABSTRACT ....................................................................................................................... iii LIST OF FIGURES ......................................................................................................... viii LIST OF TABLES ............................................................................................................. xi LIST OF SYMBOLS ........................................................................................................ xii LIST OF ABBREVIATIONS .......................................................................................... xvi ACKNOWLEDGEMENTS ........................................................................................... xviii INTRODUCTION .............................................................................................................. 1 Background and Motivation ................................................................................... 2 Statement of Problem .............................................................................................. 4 Scope and Objectives .............................................................................................. 4 Methodology ........................................................................................................... 5 LITERATURE REVIEW ................................................................................................... 7 Seismic Behavior of Concrete Filled Steel Tube Columns .................................... 7 Slenderness Ratio .............................................................................................. 8 Concrete Confinement ...................................................................................... 9 Composite Action ............................................................................................. 9 Time-Dependent Behavior of Concrete ................................................................ 11 Temporary Conditions .......................................................................................... 13 Collapse Capacity ................................................................................................. 16 Scaling of the Ground Motion Records .......................................................... 18 Hysteretic Models ........................................................................................... 19 Backbone Curve Model ................................................................ 20 Peak-Oriented Hysteretic Deterioration Model ............................ 20 Modified Hysteretic Model ........................................................... 22 Cyclic Deterioration Parameter Values ........................................ 23 ANALYSIS OF EXPERIMENTAL CIRCULAR CONCRETE FILLED STEEL TUBE COLUMNS ....................................................................................................................... 30 DESIGN OF A CIRCULAR CONCRETE FILLED STEEL TUBE COLUMN ............. 34 Design Basis Bridge .............................................................................................. 34 Force-Moment Interaction Diagrams .................................................................... 35 Analytical Model .................................................................................................. 38 Deterioration Parameters ................................................................................ 39 Analytical Hysteretic Model Results .................................................................... 41 Incremental Dynamic Analysis ............................................................................. 42 Effect of P-Δ on CCFT Behavior .......................................................................... 43 EFFECT OF TEMPORARY CONDITIONS ON CIRCULAR CONCRETE FILLED STEEL TUBE COLUMNS’ SEISMIC PERFORMANCE .............................................. 60 CONCLUSIONS............................................................................................................... 65 RECOMMENDATIONS FOR FUTURE RESEARCH ................................................... 67 Experimental Testing ............................................................................................ 67 Bond Strength as a Function of Concrete Age...................................................... 67 Parameter Study for Hysteretic Modeling of CCFT ............................................. 67 APPENDICES A: COMPARATIVE CCFT DATA.................................................................................. 69 B: BUCKLING ANALYSIS CALCULATIONS ............................................................. 71 C: INTERACTION DIAGRAM CALCULATIONS ....................................................... 75 REFERENCES ................................................................................................................. 89 vii LIST OF FIGURES 1. Bridge Piers: a) Steel, b) CFT, c) CCFT. ...................................................................... 6 2. (S /g)/– EDP Curves for Baseline SDOF Systems. ................................................. 25 a 3. Backbone Curve for Hysteretic Models. ..................................................................... 25 4. Backbone Curves for Hysteretic Models with and without P- ................................ 26 5. Peak-Oriented Hysteretic Model................................................................................. 26 6. Cyclic Deterioration in a Peak-Oriented Model. ........................................................ 27 7. Basic Strength Deterioration for Peak-Oriented Hysteretic Model. ........................... 27 8. Parameters for Peak-Oriented Hysteretic Lignos-Krawinkler Model. ....................... 28 9. Parameters for Backbone Curve for Lignos-Krawinkler Model................................. 29 10. Static Cyclic Loading Protocol for Marson and Bruneau Tests. ................................ 33 11. Design Basis Bridge: a) Bridge Elevation, b) Column Elevation, c) RC and CCFT Column Sections. ........................................................................................................ 45 12. Interaction Diagram of CCFT as Compared with HSS. ............................................. 45 13. CCFT and RC Column Interaction Diagrams as a Function of Time......................... 46 14. Time Dependent Behavior: a) Concrete Strength as a Function of Time, b) Relative Capacity of CCFT Column as a Function of Time for Moment (No Axial), Peak Moment, and Axial (No Moment). ............................................................................. 46 15. CFST64 Experimental and Predicted Analytical Hysteretic Behavior (under Static Cyclic Loading) and Monotonic Backbone Curve. .................................................... 47 16. CFST42 Experimental and Predicted Analytical Hysteretic Behavior (under Static Cyclic Loading) and Monotonic Backbone Curve. .................................................... 47 17. CFST34 Experimental and Predicted Analytical Hysteretic Behavior (under Static Cyclic Loading) and Monotonic Backbone Curve, θ = 0.15. ..................................... 48 18. CFST34 Experimental and Predicted Analytical Hysteretic Behavior (under Static Cyclic Loading) and Monotonic Backbone Curve, θ = 0.03. ..................................... 48 19. CFST51 Experimental and Predicted Analytical Hysteretic Behavior (under Static Cyclic Loading) and Monotonic Backbone Curve, θ = 0.16. ..................................... 49 20. CFST51 Experimental and Predicted Analytical Hysteretic Behavior (under Static Cyclic Loading) and Monotonic Backbone Curve, θ = 0.03. ..................................... 49 21. Hysteresis of Proposed CCFT at 3 and at 28 Days. .................................................... 50 22. Hysteresis of Proposed CCFT at 7 and at 28 Days. .................................................... 50 23. Hysteresis of Proposed CCFT at 14 and at 28 Days. .................................................. 51 24. Hysteresis of Proposed CCFT at 28 Days................................................................... 51 25. Incremental Dynamic Analysis of Proposed CCFT at 3 Days. .................................. 52 26. Incremental Dynamic Analysis of Proposed CCFT at 7 Days. .................................. 52 27. Incremental Dynamic Analysis of Proposed CCFT at 14 Days. ................................ 53 28. Incremental Dynamic Analysis of Proposed CCFT at 28 Days. ................................ 53 29. Median IDAs as a Function of Time. .......................................................................... 54 30. Backbone Curve of Proposed CCFT at 28 Days with and without P-Δ. .................... 54 31. Quasistatic Cyclic Loading (Peak-Oriented Hysteretic Curve) of Proposed CCFT at 28 Days with and without P-Δ. ................................................................................... 55 32. Dynamic Loading (Peak-Oriented Hysteretic Curve) of Proposed CCFT at 28 Days with and without P-Δ, Moment vs. Drift (Unscaled GM). ......................................... 55 33. Dynamic Loading (Peak-Oriented Hysteretic Curve) of Proposed CCFT at 28 Days with and without P-Δ, Drift vs. Time (Unscaled GM)................................................ 56 34. Dynamic Loading (Peak-Oriented Hysteretic Curve) of Proposed CCFT at 28 Days with and without P-Δ, Moment vs. Drift (GM Scaled to 2)........................................ 56 35. Dynamic Loading (Peak-Oriented Hysteretic Curve) of Proposed CCFT at 28 Days with and without P-Δ, Drift vs. Time (GM Scaled to 2). ............................................ 57 36. Incremental Dynamic Analysis, Using 44 GMs, of Proposed CCFT at 28 Days with and without P-Δ. ......................................................................................................... 57 ix