Download - UNBONDED POST-TENSIONED HYBRID COUPLED WALLS
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UNBONDED POST-TENSIONEDHYBRID COUPLED WALLSYahya C. KURAMAUniversity of Notre DameNotre Dame, Indiana
Qiang SHEN, Michael MAY (graduate students)Cooperative Earthquake Research Program on Composite and Hybrid StructuresJune 24-25, 2001Berkeley, California
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UP COUPLED WALL SUBASSEMBLAGEbeamPT tendonconnectionregionPTanchorembeddedplateanglePT tendonwall regionspiralcover plateconcretesteel
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DEFORMED SHAPE AND COUPLING FORCEScontactregiongapopeningPPVcouplingVcouplingdbzlb
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BROAD OBJECTIVESInvestigate feasibility and limitationsDevelop seismic design approachEvaluate seismic responseRESEARCH ISSUESForce/deformation capacity of beam-wall connection regionYielding of the PT steelEnergy dissipationSelf-centeringOverall/local stabilityRESEARCH PHASESSubassemblage behavior: analytical and experimentalMulti-story coupled wall behavior: analytical
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ANALYTICAL WALL MODEL (DRAIN-2DX)fiberelementkinematicconstrainttrusselement wall beam wall
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MATERIAL PROPERTIESstressstrainTENSIONcompression-only steel fiberTENSIONstressstraincompression-only concrete fiber
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ANGLE MODELbolt orPT anchorT ay seat angle at tension yieldingfiber 1angle modelfiber 2axialforceTENSIONdef.axialforceTENSIONdeformationaxialforceTENSIONdeformation= +Kishi and Chen (1990)Tay
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FINITE ELEMENT MODEL (ABAQUS)
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BEAM STRESSES
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CONCRETE STRESSES
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DRAIN-2DX VERSUS ABAQUS80050ABAQUS (rigid)ABAQUS (deformable)beam shear (kN)beam rotation (%)05d = 718 mm1000DRAIN-2DX (deformable)ABAQUS (deformable)b d = 577 mmbbeam shear (kN)beam rotation (%)contact/beam depth 501.0DRAIN-2DX (deformable)ABAQUS (deformable)beam rotation (%)5DRAIN-2DX (rigid)ABAQUS (rigid)01000beam rotation (%)beam shear (kN)
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BEAM-WALL SUBASSEMBLAGEW21x182L8x8x1-1/8ap = 0.65 in2 (420 mm2) lw = 10 ft lb = 10 ft (3.0 m) lw = 10 ft Ffpi = 0.6 fpu
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LATERAL LOAD BEHAVIOR06-602500-2500L8x8x3/406-602500-2500L8x8x1-1/8beam rotation (%)beam moment (kN.m)beam rotation (%)beam moment (kN.m)02500-250006-6no anglebeam rotation (%)beam moment (kN.m)beam moment (kN.m)MpMycover plate yieldingtension angle yieldingdecompression603000 PT-yieldingbeam rotation (%)flange yld.
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PARAMETRIC INVESTIGATIONBeam cross-section Wall lengthBeam lengthPT steel areaInitial PT stressAngle sizeCover plate size DESIGN PARAMETERS RESPONSE PARAMETERSDecompressionTension angle yieldingCover plate yieldingBeam flange yieldingPT tendon yielding 30000 6beam moment (kN.m) beam rotation (%)analytical modelbilinear estimationdecompressioncover plate yieldingtension angle yieldingPT tendon yieldingbeam flange yieldingestimation points80 3000beam moment (kN.m) beam rotation (%)decompressioncover plate yieldingtension angle yieldingPT tendon yieldingbeam flange yieldingap=560mm2ap=420mm2ap=280mm2
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PROTOTYPE WALLW21x182ap = 0.868 in2 (560 mm2)fpi = 0.65 fpu 10 ft 10 ft 10 ft107 ft(32.6 m) (3.0m 3.0m 3.0 m)PLAN VIEW20 ft 20 ft 20 ft 20 ft 20 ft28 ft 28 ft 28 ft
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COUPLED WALL BEHAVIORbase moment (kip.ft)02.5 120000roof drift (%)coupled wallright wallleft wall04roof drift (%) 120000base moment (kip.ft)coupled walltwo uncoupled walls
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CYCLIC BEHAVIOR-1.501.5-100001000-1.501.5-100001000-1.501.5-100001000base shear (kips)roof drift (%)-100001000-303base shear (kips)roof drift (%)base shear (kips)roof drift (%)base shear (kips)roof drift (%)8-story precast wall w/ UP beams6-story precast wall w/ UP beams6-story CIP wall w/ UP beams6-story CIP wall w/ embedded beams
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base shear, V (kips)DESIGN APPROACH304500roof drift, D (%)1st beam angle yielding 1st beam flange yielding wall base concrete crushing Design EQSurvival EQKK(R/m)VdesVdes/RDdesDsur
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MAXIMUM DISPLACEMENT DEMAND(Nassar & Krawinkler, 1991) br = bs = 1/4, 1/3, 1/2 a = 0.02, 0.10 Moderate and High Seismicity Design-Level and Survival-Level Stiff Soil and Medium Soil ProfilesBilinear-Elastic (BE)Elasto-Plastic (EP)Bilinear-Elastic/ Elasto-Plastic (BP)+=FFFDDD(Fbe,Dbe)kbe(brFbe,Dbe)bskbe[(1+br)Fbe,Dbe](1+bs)kbeakbeakbeR=[c(m-1)+1]1/cc= + Ta bTa+1 T
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1403.5period, T (sec)1403.5Design EQ (SAC): a=3.83, b=0.87Survival EQ (SAC): a=1.08, b=0.89ductility demand, mperiod, T (sec)ductility demand, mDUCTILITY DEMAND SPECTRA0143.5 period, T (sec)0143.5 period, T (sec)ductility demand, mductility demand, mEP, meanBP, meanBE, meanSurvival EQ (SAC): BP versus EPSurvival EQ (SAC): BP versus BE
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EXPERIMENTAL PROGRAMObjectivesInvestigate beam M-q behaviorVerify analy. modelVerify design tools and proceduresBeam-wall connection subassemblagesTen half-scale tests (angle, beam, post-tensioning properties)W10x68PT strandL4x8x3/4ap = 0.217 in2 (140 mm2) lw = 5 ft lb = 5 ft (1.5 m) lw = 5 ft strong floorfpi = 0.65 fpuElevation View (half-scale)load block
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EXPERIMENTAL SET-UPbeamwallload blockactuators
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SUMMARY AND CONCLUSIONS
Beam BehaviorAnalytical models seem to work wellGap opening governs behaviorLarge self-centering, limited energy dissipationLarge deformations with little damageBilinear estimation for beam behaviorExperimental verification
Wall BehaviorLevel of coupling up to 60-65 percentTwo-level performance based design approach~25% larger displacements compared to embedded systems
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ONGOING WORKSubassemblage testsDesign/analysis of multi-story wallsDynamic analyses of multi-story wallsACKNOWLEDGMENTSNational Science Foundation (Dr. S. C. Liu)University of Notre DameCSR American Precast, Inc.Dywidag Systems International, U.S.A, Inc.Insteel Wire ProductsAmbassador SteelIvy Steel & WireDayton/Richmond Concrete Accessories