Strain Hardening Cement Composites: Structural Design and Performance: State-of-the-Art Report of the RILEM Technical Committee 208-HFC, SC3 PDF
Preview Strain Hardening Cement Composites: Structural Design and Performance: State-of-the-Art Report of the RILEM Technical Committee 208-HFC, SC3
Strain Hardening Cement Composites: Structural Design and Performance RILEM STATE-OF-THE-ART REPORTS Volume6 RILEM, The International Union of Laboratories and Experts in Construction Materials, SystemsandStructures,foundedin 1947,is a non-governmentalscien- tificassociationwhosegoalistocontributetoprogressintheconstructionsciences, techniques and industries, essentially by means of the communication it fosters betweenresearchandpractice.RILEM’sfocusisonconstructionmaterialsandtheir useinbuildingandcivilengineeringstructures,coveringallphasesofthebuilding processfrommanufactureto use and recyclingof materials. More informationon RILEManditspreviouspublicationscanbefoundonwww.RILEM.net. The RILEM State-of-the-Art Reports (STAR) are produced by the Technical Committees. They represent one of the most important outputs that RILEM generates– high level scientific and engineeringreportsthat providecutting edge knowledgeinagivenfield.TheworkoftheTCsisoneofRILEM’skeyfunctions. Members of a TC are experts in their field and give their time freely to share theirexpertise.Asa result,the broaderscientific communitybenefitsgreatlyfrom RILEM’sactivities. RILEM’sstatedobjectiveistodisseminatethisinformationaswidelyaspossible tothescientificcommunity.RILEMthereforeconsiderstheSTARreportsofitsTCs asofhighestimportance,andencouragestheirpublicationwheneverpossible. Theinformationinthisandsimilarreportsismostlypre-normativeinthesense thatitprovidestheunderlyingscientificfundamentalsonwhichstandardsandcodes ofpracticearebased.Withoutsuchasolidscientificbasis,constructionpracticewill belessthanefficientoreconomical. It is RILEM’s hope that this information will be of wide use to the scientific community. Forfurthervolumes: http://www.springer.com/series/8780 Keitetsu Rokugo • Tetsushi Kanda Editors Strain Hardening Cement Composites: Structural Design and Performance State-of-the-Art Report of the RILEM Technical Committee 208-HFC, SC3 123 Editors KeitetsuRokugo TetsushiKanda GifuUniversity KajimaTechnical Gifu ResearchInstitute Japan Tokyo Japan ISBN978-94-007-4835-4 ISBN978-94-007-4836-1(eBook) DOI10.1007/978-94-007-4836-1 SpringerDordrechtHeidelbergNewYorkLondon LibraryofCongressControlNumber:2012941160 ©RILEM2013 Nopartofthisworkmaybereproduced,storedinaretrievalsystem,ortransmittedinanyformorby anymeans,electronic,mechanical,photocopying,microfilming,recordingorotherwise,withoutwritten permissionfromthePublisher,withtheexceptionofanymaterialsuppliedspecificallyforthepurpose ofbeingenteredandexecutedonacomputersystem,forexclusiveusebythepurchaserofthework. Printedonacid-freepaper SpringerispartofSpringerScience+BusinessMedia(www.springer.com) Contents 1 Introduction ................................................................... 1 2 StructuralBehaviorandDesignofR/SHCCElements................... 3 2.1 FlexuralCharacteristicsandDesign..................................... 3 2.1.1 FlexuralCapacityofSHCCMembers.......................... 3 2.1.2 FlexuralCrackingBehavior..................................... 9 2.1.3 SizeEffectonFlexuralBehavior................................ 12 2.2 ShearCharacteristicsandDesign ....................................... 14 2.2.1 Introduction...................................................... 14 2.2.2 ReviewofPreviousStudies ..................................... 15 2.2.3 EvaluationofShearCapacityofStructuralMembers.......... 28 2.2.4 ConcludingRemarks ............................................ 40 2.3 FiniteElementModeling ................................................ 41 2.3.1 Introduction...................................................... 41 2.3.2 ContinuumBasedModels....................................... 41 2.3.3 SmearedCrackandHomogenizationBasedModels........... 43 2.3.4 ModifiedConcreteModels...................................... 46 2.3.5 IndividualCrackBasedModel.................................. 47 2.4 DuctilityandAnti-seismicDesign ...................................... 49 2.4.1 ComparisonofStructuralBehaviorBetween R/SHCCElementsandR/CElements.......................... 49 2.4.2 DesignConceptofRCElementsandAdvantage ofSHCCUtilization............................................. 52 References...................................................................... 54 3 ApplicationofSHCC ......................................................... 59 3.1 Introduction .............................................................. 59 3.2 AConceptforUseofNewMaterials ................................... 60 3.2.1 PerformanceBasedDesignforSHCCApplication............ 60 3.2.2 PotentialApplication............................................ 61 3.3 SHCC’sMaterialCharacterizationforApplication.................... 63 v vi Contents 3.4 ApplicationExamples ................................................... 66 3.4.1 AdvantagesforR/SHCCApplication........................... 66 3.4.2 UseofTensilePerformanceforTunnelLining................. 67 3.4.3 UseofTensileResistanceforSteelFloorDeck................ 69 3.4.4 UseofSteelProtectionCapabilityforSurface ProtectionAgainstCarbonation................................. 70 3.4.5 Seismic Application of Coupled Tensile ResistanceandSteelProtectionCapability..................... 73 3.4.6 JointandOverlayApplications ................................. 73 3.5 ConclusionsandFutureTasks........................................... 76 References...................................................................... 77 RILEMPublications.............................................................. 79 RILEMPublicationspublishedbySpringer................................... 87 Index................................................................................ 89 Chapter 1 Introduction Strain Hardening Cement Composites, SHCC hereafter, demonstrate excellent mechanicalbehaviorshowingtensilestrainhardeningandmultiplefinecracks.This strainhardeningbehaviorimprovesthedurabilityofconcretestructuresemploying SHCCandthemultiplefinecracksenhancestructuralperformance.Reliabletensile performance of SHCC enables us to design structures explicitly accounting for SHCC’s tensile properties. Reinforced SHCC elements (R/SHCC) indicate large energyabsorbingperformanceunderlargeseismicexcitation. Reinforcedconcretestructuresaresubjectedtovarioustypesofloading,suchas deadload,liveload,andseismic load.Againstthoseloads,R/SHCC elementscan bedesignedbysuperimposingre-barperformanceandSHCC’stensileperformance. TheestimationofSHCC’sshearresistancecontributionindesign,whichisdeduced from SHCC’s tensile property, requires various investigations since the shear resistancemechanismisusuallycomplicated. This State-of-the-Art Report is written collectively by members of Sub- committeethreeoftheRILEMTC208-HFC.Thereportfocusesonflexuraldesign, sheardesign,FEmodelingandanti-seismicdesignofR/SHCCelementsaswellas applicationexamples.Establishingdesignmethodsfornewmaterialsusuallyleads toexploringapplicationareasandthistrendshouldbedemonstratedbycollecting actualapplicationexamplesofSHCCinstructures. Exploring SHCC applications necessitates establishing structural design and constructionpracticemanualsataveryearlyopportunity.Hence,theJapanSociety ofCivilEngineerspublishedthe“Recommendationsfordesignandconstructionof highperformancefiberreinforcedcementcompositewithmultiplecracks”in2007, which contains technical knowledge accumulated in conjunction with the activity of RILEM TC 208-HFC. This recommendation can be freely obtained from the websiteofJSCE.TheRILEMTC208-HFCSubcommitteethreeactivitiesdescribed inthisreportareintendedtodevelopmorereliableandpracticalrecommendations byreflectingthelatestresearchresults. (K.Rokugo) K.RokugoandT.Kanda(eds.),StrainHardeningCementComposites: 1 StructuralDesignandPerformance,RILEMState-of-the-ArtReports6, DOI10.1007/978-94-007-4836-1 1,©RILEM2013 Chapter 2 Structural Behavior and Design of R/SHCC Elements Abstract Structural behavior of steel reinforced SHCC (R/SHCC) elements are discussedinthischapter.Basedonthediscussion,designapproachesforR/SHCC arealsoinvestigated.First,inflexure,R/SHCCappearstoshowsimilarbehaviorto regularR/CanditsdesigncanbeachievedinextensionofR/Cdesignbyconsidering shortfibercontributionagainstflexuraltensilestress.Second,theshearbehaviorof SHCC clarified by Finite Element analysis is reviewed. Then the state of the art insheardesignapproachissummarized.Finally,structuralductilityunderseismic loadingandseismicdesignconceptforbeamsandcolumnsarediscussed. Keywords Flexural capacity • Shear capacity • Cracking • Ductility • Macro model • Finiteelementanalysis 2.1 Flexural Characteristics andDesign 2.1.1 FlexuralCapacityofSHCCMembers 2.1.1.1 General Due to its capability of bearing tensile forces after cracking by the bridging effect of fibers, the design of SHCC flexural members can be streamlined by directly incorporating this effect. In other words, design taking into account the tensile capacity of SHCC becomes possible by assuming a perfect elasto-plastic constitutivemodelasshowninFig.2.1. To make the effect of SHCC’s tensile properties on the cross-sectional perfor- manceofflexuralmemberseasytounderstand,Fig.2.2showstheconceptofstrain and stress distributions of a flexural member cross-section having SHCC on the tensionside incomparisonwiththose ofanordinaryreinforcedconcretemember. When SHCC is used on the tensionside, the entirecross-sectionincludingSHCC K.RokugoandT.Kanda(eds.),StrainHardeningCementComposites: 3 StructuralDesignandPerformance,RILEMState-of-the-ArtReports6, DOI10.1007/978-94-007-4836-1 2,©RILEM2013 4 2 StructuralBehaviorandDesignofR/SHCCElements Fig.2.1 Tensilestress–strain curveofSHCC ftyk gc s s e str e sil n e T 0 ftyk (Ec gc) etu Tensile strain a (comp.) Neutral Plain concrete axis Steel ECC (tens.) Strain distribution Stress distribution SHCC is used on the tension side b (comp.) Neutral axis Plain concrete Steel (tens.) Strain distribution Stress distribution Solid reinforced concrete Fig.2.2 Distributionofstressandstrain bears the tensile forces, reducing the tensile stress of tensile reinforcement even under the action of a tensile strain exceeding the yield strain of reinforcement. Underthesamebendingmoment,theneutralaxisofconcretehavingSHCConthe tensionsideshiftstothetensionsiderelativetosolidreinforcedconcrete,increasing the compression zone in the concrete. In other words, the use of SHCC on the tensionsidehasthesameeffectasanincreaseinthecross-sectionalareaoftensile reinforcement. Thecompressivestress–straincurveshouldbeassumedtocalculatetheultimate capacity of section failure for the members subjected to a bending moment or a bendingmomentandaxialcompressiveforces.Anexampleofacompressivestress– strainrelationship,whichisderivedfromtheresultsoftestsoncylinderspecimens 2.1 FlexuralCharacteristicsandDesign 5 Fig.2.3 Exampleof 50 Specimen 1 compressivestress–strain curve a) Specimen 2 P40 M Specimen 3 s ( es30 str e v si20 s e pr m 10 o C 0 0 0.2 0.4 0.6 0.8 1 Compressive strain (%) Fig.2.4 Compressive stress–straincurveinJSCE Recommendations 0.85 fc′d σ′c s s e str e v si s e pr m Co σc′ = 0.85 fc′d εc′ 2− εc′ εm′ εm′ 0 εm′ Compressive strainεc′ of100mmindiameterand200mminheight,isshowninFig.2.3.Asshowninthe figure,thestrainvalueatthepeakstressis0.4%(0.004)approximately.Thisstrain value is greater than 0.002, i.e. that of ordinary concrete. This shows one of the characteristicsofSHCC;thestressdecreasesslowlywithincreasingstrainafterthe maximumloadduetotheconfinementeffectoffiberbridging. TotakeintoaccounttheseSHCCmaterialcharacteristicsinstructuraldesign,itis necessarytodeterminethecompressivestress–strainrelationofSHCC.According totheJSCERecommendations,thestress–strainrelationshowninFig.2.4maybe usedforthecalculationoftheflexuralcapacityofthesectionwhenappropriatetest data are notavailable [1].The strain "’ at the peakstress can be set equalto the m strain at reachingthe compressivestrength obtainedfromthe compressiontest on thecylindricalspecimen. The influence of the exact shape of the compressive stress–strain curve on the flexuralcapacityofSHCCmembersismarginal,ifthecompressivestrengthandthe
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