University of Missouri, Rolla - Network for Earthquake Engineering ...

ParticipantsUniversity of Nevada, RenoDavid Sanders (Project PI)• 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(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 ActionsSystem to Component to System• Functional Constraints - curved or skewedbridges• Geometric Considerations - uneven spans ordifferent column heights• Multi-directional Earthquake Motions -significant vertical motions input or nearfield fling impacts• Structural Constraints - stiff deck, movementjoints, soil condition and foundations

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 Responseaxial force: kN310029002700250023002100190017001500Santa Monica Freeway, Pier 6TransverseTrans + LongTrans + Vert8 8.5 9 9.5 10 10.5 11time: seconds

Significance of Torsion• Interaction of Shear-Torsion results in early coverspalling of non-circular/rectangular cross-sectionsdue to circulatory shear stresses.• What are the effects of warping on the flexural andshear capacity of columns?• What is the impact of multiple loadings on thintubetheory?• What are the effects on the curvature ductility andlocation of the plastic hinge?

M-V-T InteractionsBending-ShearShear-TorsionCombination ofBending-Shear-Torsion

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 moderateseismicity• Bidirectional bending moment -non-circularcross-sections• Type of Loading – Slow Cyclic, Pseudo-dynamicand shake table/dynamic

Pre-test System Analysis• Perform seismic simulations of bridge systemsunder combined actions to study effects of variousbridge components on global and local seismicresponse behavior of bridge system• Bridge superstructure• Columns (Piers)• Foundations and surrounding soil• Embankments• Nonlinear soil-foundationfoundation-structure interaction• Multi-directional motions

Analysis• Selected 4 ground motion suites that incorporate thesite-dependent probabilistic hazard analysis and groundmotion disaggregation analysis.• Selected 2 bridge prototypes that are distinctive interms of structural characteristics and dynamicproperties.• Conducted time history analysis of prototype bridgessubjected to multi-directional ground shakings andevaluate the effect of vertical motions on seismicdemand.• Implemented nonlinear structural and foundationelements.

StructuralCharacteristicsSpan/SpanLengthPier TypeAbutment TypeFoundationExpansionJointsForce ResistingMechanismExamples of Prototype BridgesDesign Example #4 Design Example #8Three-span continuous,320 ft longTwo-column integral bent,pinned at baseSeatSpread FootingExpansion Bearings &Shear KeysLongitudinal: intermediatebents & free movement atabutmentsTransverse: intermediatebent columns &abutmentsFive-span continuous,500 ft longTwo-column integral bent,monolithic at top and baseStub abutment/diaphragmPileExpansion BearingsLongitudinal: intermediatebents and abutment backfillTransverse: intermediatebent columns and abutmentbackfill

axial force(kip)Structural Response of Bridge #85.0E+02time(s)0.0E+00-5.0E+020.0 5.0 10.0 15.0 20.0shear force_x(kip)shear force_z(kip)1.0E+03-1.0E+03-1.5E+03-2.0E+03-2.5E+031.5E+021.0E+025.0E+010.0E+000.0-5.0E+015.0 10.0 15.0 20.0-1.0E+02time(s)-1.5E+028.0E+026.0E+024.0E+022.0E+02-4.0E+02-6.0E+02-8.0E+02Force DemandBottom of Column inBent#3Top of Column in Bent#10.0E+00-2.0E+020.0 5.0 10.0 15.0 20.0time(s)Bottom of Column in Bent#1relative disp._z(ft)axial relative disp.(ft)relative disp._x(ft)1.0E-015.0E-020.0E+000.0 5.0 10.0 15.0 20.0-5.0E-02-1.0E-018.0E-016.0E-014.0E-012.0E-01-4.0E-01-6.0E-015.0E-03-5.0E-03-1.0E-02-1.5E-02Displacement Demand0.0E+000.0 5.0 10.0 15.0 20.0Column in Bent#3Column in Bent#1time(s)0.0E+00-2.0E-010.0 5.0 10.0 15.0 20.0Column in Bent#1time(s)Tensiontime(s)1986 N. Palm Springs Earthquake

Pre-test Component Analysis• Perform pretest simulations of test specimenswith 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 theframework of UI-Simcorfor pseudo-dynamic dynamic hybridtesting

Analytical Program• Development Inelastic Models for RC Sectionsunder 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

Development Inelastic Models for RCSections under Combined LoadingDeficiencies of Available Analytical Models:• Current Inelastic Frame software Packages(e.g. OpenSees, , Zeus-NL,FedeasLab) ) focuson flexural behavior of RC members only.• The combined axial/shear/flexural/torsionalbehavior is not considered in current models.

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

UMR Test SetupStrong W all Load CellHydralic JackLoad StubHydraulic ActuatorsSteel Strands(Inside C olum n)Test UnitSupport BlocksStrong Floor

Test SetupStrong WallStrong WallLoading FrameHydraulic ActuatorsLoad StubTest Unit

UMR Test SetupPosition of (2) Horizontal Actuators.Actuators Position for S-PatternloadingTest Unit (InterlockingSpiral Column Setup for Bi-AxialBending Shown)ψθLoading FrameRotation Angle –Twist/TorsionTest Unit Offset Anglefor Bi-Axial BendingLoadingFrame

Shape Ht. Scale Design Directions DescriptionM01 -24 108 1:2 High U, A1Level 1axial-high shearflexure(I01)(a)M02 -24 108 1:2 High U, T, A1 M01 with torsion (e)M05 -24 108 1:2 High U, T, A1 M02 with high torsion (c)M06 -24 150 1:2 High U, T, A1 high torsion (d)M07 -24 150 1:2 Mod. U, A1 M01 with moderate details (b)M08 -24 150 1:2 High T, A2 Level 2 axial-torsion (g)M09 -24 150 1:2 High U, T, A2 Level 2 Axial (f)M10 -24x48 150 1:2 High U (m) Level 1 axial-low shear- (b)M11 -24x48 150 1:2 High U (M) M10 with bidirectional M (b)M12 - 24x48 150 1:2 High U, T (m) M10 with torsion (d)M13 - 24x48 150 1:2 High U, T (M) M11 with torsion (d)M14 - 24x24 108 1:2 High U Level 1 axial-high shear (a)M15- 24x24108 1:2 Mod. U, TM14 with high torsion andM16M17- 24x24-24-24-24156 1:2 Mod. U, T144156108UMR Test Matrix1:21:21:2HighHighHighEarthquakeTesting in Junemoderate details (c)M15 with high torsion andmoderate details (d)Prototype bridge evaluation –DONE AT UIUC by UMR.

Column Fabrication

Column TestingSpecimen M07:Ductility 8

Large Testing Facility, UIUC

Large Testing Facility, UIUC• Three 6 DOF loading and boundarycondition boxes of capacity 3000kNto 4500kN• Displacement capacity +/- 250 mmper box• Reaction wall ~15x9x8 meters• Three advanced high speed DACsystems• Video and J-Camera Jdata capture• Simulation Coordinator UI-SIMCORfor multi-site hybrid simulationDisp.Forc.UI-SimCorForc.Disp.ExperimentModuleStatic AnalysisModule

Small Scale Testing Facility, UIUC

UIUC Experiment• MISST test (previous multi-site test at UIUC) will provide the test bedfor the loading protocols• Tests of 3 large scale and 4 small scale bridge columns with differentferentaspect ratios and seismic design details using MUST-SIM SIM Facility• 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 bridgesystem analysisTest at UIUCSmall Scale Test Large Scale Test Test with UMRNEES-R

• Current testingSmall-Scale Scale Testing• Several 1/16 scaled piers are currently being tested• Used to evaluate system and material/pier designTest SetupAfter Test

UNR Shake Table Facility•Previous Tests haveFocused on UnidirectionalMotion.•System of Decoupling theVertical Load and InertialMass has been used.•Vertical Load wasHeld Constant.A system will now be used to decouple variableaxial load from the inertial load with bi-directional lateral shaking.

UNR ProgramShape Ht. Scale Design Directions Description104CA,E1,E2 Constant axial, low1:3 High,T shear, torsion104VA,E1,E2 N01 but with variable1:3 High,T axial load72CA,E1,E2 Constant axial, high1:3 High,T shear, torsion72VA,E1,E2 N03 but with variable1:3 High,T axial load72Variable axial, high- 12x20 1:4 High VA,E1,E2shear- 12x20 72VA,E1,E21:4 HighN05 with torsion,T- 12x20 72VA,E3,E4 N06 with near field1:4 High,T motions72VA,E1,E2- 12x20 1:4 HighN07 with high torsion,T2N01 - 16N02 - 16N03 - 16N04 - 16N05N06N07N08

UMR Test at UIUCUI-SIMCORTested StructureDisp.Structural ModuleForce(Zeus-NL)ForceDisp.Soil & FoundationModule(OpenSees)

International Cooperation• University of MexicoShape Ht. Scale Design Directions DescriptionX01 - 20 x 20 80 1:1.2 High CA, U Strengthened priorto testingX02 - 20 x 20 80 1:1.2 High CA, U X01 with secondrepair schemeX03 - 20x80 120 1:2 High CA, U1 BidirectionalMotion 1X04 - 20x80 120 1:2 High CA, U2 BidirectionalMotion 2

Educational Activities• UCIST shake tablesincorporated forhands-on exercisesand experiments• Existing K-12 Koutreach programs will beenhanced with additional modules• UNR: Summer camps and ME2L program• UIUC: Engineering Open House• UMR: High school engineering summer course• WU: GK-12 Program

Educational Activities• Modules to be developed to enhance curriculum onundergraduate and graduate levels• Undergraduates involved in research through REUprograms• Encourage students from underrepresented groupsthrough Minority Engineering Program, GAMES,MERGE, and GetSet program• Online continuing education course to be developed atUMR for practicing Engineers

UMR as NEES-POPUMR

UMR as NEES-POP

UMR as NEES-POP

Questions??