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 System to Component to System Causes of Combined Actions System to Component to System 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

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. What are the effects of warping on the flexural and shear capacity of columns? What is the impact of multiple loadings on thin- tube theory? 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

Analysis Selected 4 ground motion suites that incorporate the site-dependent probabilistic hazard analysis and ground motion disaggregation analysis. Selected 4 ground motion suites that incorporate the site-dependent probabilistic hazard analysis and ground motion disaggregation analysis. Selected 2 bridge prototypes that are distinctive in terms of structural characteristics and dynamic properties. Selected 2 bridge prototypes that are distinctive in terms of structural characteristics and dynamic properties. Conducted time history analysis of prototype bridges subjected to multi-directional ground shakings and evaluate the effect of vertical motions on seismic demand. Conducted time history analysis of prototype bridges subjected to multi-directional ground shakings and evaluate the effect of vertical motions on seismic demand. Implemented nonlinear structural and foundation elements. Implemented nonlinear structural and foundation elements.

Examples of Prototype Bridges Structural Characteristics Design Example #4 Design Example #8 Span/Span Length Three-span continuous, 320 ft long Five-span continuous, 500 ft long Pier Type Two-column integral bent, pinned at base Two-column integral bent, monolithic at top and base Abutment Type Seat Stub abutment/diaphragm Foundation Spread Footing Pile Expansion Joints Expansion Bearings & Shear Keys Expansion Bearings Force Resisting Mechanism Longitudinal: intermediate bents & free movement at abutments Transverse: intermediate bent columns & abutments Longitudinal: intermediate bents and abutment backfill Transverse: intermediate bent columns and abutment backfill

Column in Bent#3 Column in Bent#1 Displacement Demand Tension Bottom of Column in Bent#1 Structural Response of Bridge #8 Bottom of Column in Bent#3 Top of Column in Bent#1 Force Demand 1986 N. Palm Springs Earthquake

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

Development Inelastic Models for RC Sections under Combined Loading Deficiencies of Available Analytical Models: Current Inelastic Frame software Packages (e.g. OpenSees, Zeus-NL, FedeasLab) focus on flexural behavior of RC members only. Current Inelastic Frame software Packages (e.g. OpenSees, Zeus-NL, FedeasLab) focus on flexural behavior of RC members only. The combined axial/shear/flexural/torsional behavior is not considered in current models. The combined axial/shear/flexural/torsional behavior is not considered in current models.

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

Test Setup

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

Shape Ht. Scale Design Directions Description M :2 High U, A1 Level 1axial-high shear- flexure(I01) (a) M :2 High U, T, A1 M01 with torsion (e) M :2 High U, T, A1 M02 with high torsion (c) M :2 High U, T, A1 high torsion (d) M :2 Mod. U, A1 M01 with moderate details (b) M :2 High T, A2 Level 2 axial-torsion (g) M :2 High U, T, A2 Level 2 Axial (f) M10 -24x :2 High U (m) Level 1 axial-low shear- (b) M11 -24x :2 High U (M) M10 with bidirectional M (b) M x :2 High U, T (m) M10 with torsion (d) M x :2 High U, T (M) M11 with torsion (d) M x :2 High U Level 1 axial-high shear (a) M x :2 Mod. U, T M14 with high torsion and moderate details (c) M x :2 Mod. U, T M15 with high torsion and moderate details (d) M :2 High Earthquake Prototype bridge evaluation– DONE AT UIUC by UMR. Testing in June UMR Test Matrix

Column Fabrication

Column Testing Specimen M07: Ductility 8

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

UIUC Experiment UIUC Experiment MISST test (previous multi-site test at UIUC) will provide the test bed for the loading protocols MISST test (previous multi-site test at UIUC) will provide the test bed for the loading protocols Tests of 3 large scale and 4 small scale bridge columns with different aspect ratios and seismic design details using MUST-SIM Facility Tests of 3 large scale and 4 small scale bridge columns with different aspect ratios and seismic design details using MUST-SIM Facility Column test with UMR under different loading conditions Column test with UMR under different loading conditions  Verify local and global analytical part of the hybrid simulation  Provide an opportunity for researchers outside of a NEES facility  Detailed design of UIUC and UNR experiments will be guided by bridge system analysis Test at UIUC Small Scale Test Large Scale Test Test with UMR NEES-R

Small-Scale Testing Current testing Current testing Several 1/16 scaled piers are currently being tested Several 1/16 scaled piers are currently being tested Used to evaluate system and material/pier design Used to evaluate system and material/pier design Test Setup After Test

UNR Shake Table Facility   Previous Tests have Focused on Unidirectional Motion.   System of Decoupling the Vertical Load and Inertial Mass has been used.   Vertical Load was Held Constant. A system will now be used to decouple variable axial load from the inertial load with bi-directional lateral shaking.

UNR Program

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

International Cooperation University of Mexico University of Mexico

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

UMR as NEES-POP UMR

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