NEESR-SG-2005 Seismic Simulation 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

Participants University of Nevada, Reno David Sanders (Project PI) University of Missouri, Rolla University of Missouri, Rolla Abdeldjelil “DJ” Belarbi (co-PI) Abdeldjelil “DJ” Belarbi (co-PI) Pedro Silva Pedro Silva Ashraf Ayoub Ashraf Ayoub University of Illinois- Champaign-Urbana University of Illinois- Champaign-Urbana Amr Elnashai (co-PI) Amr Elnashai (co-PI) Reginald DesRoches (GaTech) 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

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

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

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

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?

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

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

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 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 Bridge superstructure Columns (Piers) Columns (Piers) Foundations and surrounding soil Foundations and surrounding soil Embankments Embankments Nonlinear soil-foundation-structure interaction Nonlinear soil-foundation-structure interaction Multi-directional motions Multi-directional motions

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

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

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

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

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

Large Testing Facility, UIUC

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

Small Scale Testing Facility, UIUC

UNR Shake Table Facility

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

UMR Program

UIUC – MUST-SIM Program

UNR Program

International Cooperation University of Mexico University of Mexico E-Defense - ????? E-Defense - ?????

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

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

Questions??