NEESR-SG-2005

1. NEESR-SG-2005 SeismicSimulation and Design of Bridge Columns under Combined Actions, and Implications on System Response University of Nevada, Reno University of Missouri, Rolla University of Illinois, Champaign-Urbana University of California, Los Angeles Washington University, St. Louis

2. University of Missouri, Rolla Abdeldjelil “DJ” Belarbi (co-PI) Pedro Silva Ashraf Ayoub University of Illinois-Champaign-Urbana Amr Elnashai (co-PI) Reginald DesRoches (GaTech) University of California, Los Angeles Jian Zhang (co-PI) Washington University, St. Louis Shirley Dyke (co-PI) University of Mexico Sergio Alcocer ParticipantsUniversity of Nevada, RenoDavid Sanders (Project PI)

3. Causes of Combined Actions • Functional Constraints - curved or skewed bridges • Geometric Considerations - uneven spans or different column heights • Multi-directional Earthquake Motions -significant vertical motions input or near field fling impacts • Structural Constraints - stiff deck, movement joints, soil condition and foundations

4. Field Evidences of Damage • Northridge, USA (1994) • Significant Vertical Motions (V/H=0.98 to 1.79) • Large Horizontal Motions (Ah=0.62g to 1.18g) • RC Bridge Pier Failures • Combined Shear/Buckling Failure of Column • Hyogo Ken Nanbu, Japan (1995) • Significant Vertical Motions (V/H=1.96 to 1.63) • Medium Horizontal Motions (Ah=0.35g to 0.29g) • RC Pier Failed at Central Section • RC Piers Collapse

5. Significance of Vertical Motion • Effects of Vertical Motions on Structures • Direct Compressive Failure • Reduction of Shear and Moment Capacity • Increase in Shear and Moment Demand • Axial Force Response

6. Significance of Torsion • Interaction of Shear-Torsion results in early cover spalling of non-circular/rectangular cross-sections due to circulatory shear stresses. • Treatment of torsion is based on thin-tube theory. • What are the effects of warping on the flexural and shear capacity of columns? • What is the impact of Shear-Torsion on plastic hinges? • What are the effects on the curvature ductility and location of the plastic hinge?

7. Bending-Shear Shear- Torsion Combination of Bending-Shear- Torsion M-V-T Interactions

8. Parameters • Cross-section - Circle, Interlocking Spiral, Square • Column aspect ratio - moment/shear ratio • Torsion/shear ratio - high and low torsion • Level of axial loads • Level of detailing for high and moderate seismicity • Bidirectional bending moment - non-circular cross-sections • Type of Loading – Slow Cyclic, Pseudo-dynamic and shake table/dynamic

9. Pre-test System Analysis • Perform seismic simulations of bridge systems under combined actions to study effects of various bridge components on global and local seismic response behavior of bridge system • Bridge superstructure • Columns (Piers) • Foundations and surrounding soil • Embankments • Nonlinear soil-foundation-structure interaction • Multi-directional motions

10. Pre-test Component Analysis • Perform pretest simulations of test specimens with realistic loading and boundary conditions • Provide guidance for tests conducted • Optimize number and parameters of test specimens • Identify realistic loading and boundary conditions • Integrate various analytical models into the framework of UI-Simcor for pseudo-dynamic hybrid testing

11. Analytical Program • Development Inelastic Models for RC Sections under Combined Loading • Modeling of Specimens tested under Pseudo-Dynamic/Dynamic Conditions • Complex and Simplified Tools • Parametric Studies • Bridge System Analysis • Development of Seismic Design Criteria

12. Experimental Program • Experimental investigation of columns under multi-directional loadings with varying levels of axial force and axial-flexure interaction ratios linked to analysis. • Slow cyclic tests at UMR. • Pseudo-dynamic tests at UIUC • Dynamic tests at UNR • Integrated bridge test managed by UMR, tested at UIUC

13. (1) Horizontal Actuator Loading Frames Load Stub (2) Vertical Actuators Unit Tie Downs (2) Horizontal Actuators Test Unit Unit Base Strong Floor /Wall Tie Downs for (1) Horizontal Actuator Test Unit UMR Test Setup

14. Position of (2) Horizontal Actuators. Actuators Position for S-Pattern loading Test Unit (Interlocking Spiral Column Setup for Bi-Axial Bending Shown)   Loading Frame Loading Frame Rotation Angle – Twist/Torsion Test Unit Offset Angle for Bi-Axial Bending UMR Test Setup

15. Large Testing Facility, UIUC

16. Large Testing Facility, UIUC • Three 6 DOF loading and boundary condition boxes of capacity 3000kN to 4500kN • Displacement capacity +/- 250 mm per box • Reaction wall ~15x9x8 meters • Three advanced high speed DAC systems • Video and J-Camera data capture • Simulation Coordinator UI-SIMCOR for multi-site hybrid simulation

17. Small Scale Testing Facility, UIUC

18. UNR Shake Table Facility

19. UNR Shake Table Facility

20. UNR Shake Table Facility

21. Tested Structure UI-SIMCOR Disp. Disp. Force Force Structural Module (Zeus-NL) Soil & Foundation Module (OpenSees) UMR Test at UIUC

22. UMR Program

23. UIUC – MUST-SIM Program

24. UNR Program

25. International Cooperation • University of Mexico • E-Defense - ?????

26. Educational Activities • UCIST shake tables incorporated for hands-on exercises and experiments • Existing K-12 outreach programs will be enhanced with additional modules • UNR: Summer camps and ME2L program • UIUC: Engineering Open House • UMR: High school engineering summer course • WU: GK-12 Program

27. Educational Activities • Modules to be developed to enhance curriculum on undergraduate and graduate levels • Undergraduates involved in research through REU programs • Encourage students from underrepresented groups through Minority Engineering Program, GAMES, MERGE, and GetSet program • Online continuing education course to be developed at UMR for practicing Engineers

28. Questions??