混凝土梁柱联接部位的加固英文翻译.docx

混凝土梁柱联接部位的加固英文翻译.docx

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混凝土梁柱联接部位的加固英文翻译

本科毕业设计（论文）

英文专题

专业名称：

土木矿建

年级班级：

土木单招06-1班

学生姓名：

XXX

指导教师：

余永强

河南理工大学土木工程学院

二○一○年六月十日

Reinforcementofconcretebeam–columnconnectionswithhybridFRPsheet

AbstractThepaperdescribestheresultsoftestsonprototypesizereinforcedconcreteframespecimenswhichweredesignedtorepresentthecolumn–beamconnectionsinplaneframes.Thetestsweredevisedtoinvestigatetheinfluenceoffibrereinforcedplastic（FRPreinforcementappliedtoexternalsurfacesadjacenttothebeam–columnconnectiononthebehaviourofthetestspecimensunderstaticloading.OfparticularinterestunderstaticloadingwastheinfluenceofFRPreinforcementonthestrengthandstiffnessofbeam–columnconnection.Asakeytothestudy,thehybridFRPcompositesofE-glasswovenroving（WR）andplaincarboncloth,combinedwithchoppedstrandmat（CSM）,glassfibertape（GFT）withavinyl-esterresinweredesignedtoexternallyreinforcethejointoftheconcreteframe.TheresultsshowthatretrofittingcriticalsectionsofconcreteframeswithFRPreinforcementcanprovidesignificationstrengtheningandstiffeningtoconcreteframesandimprovetheirbehaviourunderdifferenttypesofloading.TheselectionsoftypesofFRPandthearchitectureofcompositesinordertoimprovethebondingandstrengthoftheretro-fittingwerealsodiscussed.

AuthorKeywords:

Concretestructure;Strengthening;Rehabilitation;HybridFRPcomposite;Wrappingtechnique

1.Introduction

Awidelyadoptedtechniqueforretrofittingconcretestructureistousesteeljacketsplacedaroundexistingconcretecolumns[1and2].Theuseofsteelencasementtoprovidelateralconfinementtotheconcreteincompressionhasbeenstudiedextensively[3and4],andhasshownincreaseinthecompressionloadcarryingcapacityandductilityoftheconcretecolumns.However,theshortcomingsofthistechniquearethatitsuffersfromcorrosionsaswellasinherentdifficultiesduringpracticalapplications.Fibrereinforcedplastic（FRP）,ontheotherhand,isincreasinglybeingusedtoreinforceconcrete,masonryandtimberstructures.TheloadcarryingcapacityandserviceabilityofexistingstructurescanbesignificantlyaugmentedthroughexternallyretrofittingcriticalsectionswithFRPsheeting.InrecentyearsFRPmaterialswithwiderangeoffibretypesofglass,aramidorcarbonprovidedesignerswithanadaptableandcost-effectiveconstructionmaterialwithalargerangeofmodulusandstrengthcharacteristics.Comparingwithtraditionalrehabilitationtechniques,theFRPcompositeshavehighspecificstrength/stiffness,flexibilityindesignandreplacementaswellasrobustnessinunfriendlyenvironments.WithFRPcompositesitispossibleandalsonecessarytoachievethebeststrengtheningresultsbyoptimisingtheconstitutematerialsandarchitecture.OptimisationoftheconstitutematerialsandarchitecturebecomesessentialinordertoutilisethesuperiorityofFRPcompositesinapplicationofrehabilitation[5,6,7,8and9].Itwasfoundthatwindingofcarbonfiber/epoxycompositesaroundsquareconcretecolumnscanincreasetheloadcarryingcapacityby8–22%,dependingontheamountoffibresusedandtreatmentsofsubstratesurface[10].Theuseofresininfusiontechniquewasshowntocontributetosubstantialimprovementsincompositewrappingefficiency,andtheuseofwovenglassroving,asthereinforcementincompositeswrapping,wasfoundtosignificantlyincreasebothloadcarryingcapacityanddeformationresistancecapacityoftheconcretestubs[2].Furthermore,throughtheuseofglass/carbonhybridreinforcementswithanepoxyresin,replicationofinitialperformanceofconcretestubssubjectedtodeteriorationwasshownpossible,withasimultaneousfurtherimprovementinloadcarryingcapacity.Intermsoftheeffectsoforientationandthicknessofthecompositeswarps,itwasfoundthatthepredominantuseofreinforcementsinthehoopdirectionwouldresultinhighefficiency[11].Despitethelargenumberofresearchcarriedout,oneshortcomingofmoststudieshasbeenthattheywerelimitedtosimplesmallsizecomponents,suchasconcretecylinders,ratherthanrealstructures.Furthermore,itisessentialtostudytheoptimisationofcompositesarchitecturesintermsofcosteffectivenessincludingmaterialsandprocessingmethods.ThisimpliesthatthereinforcementofinfrastructurewithFRPcompositesshouldutilisetheadvantagesofvariousmaterials,notonlycarbonfiberswithepoxyresin,butalsoglassfiberorhybridofcarbon/glassfibreswithotherpolymerresins.Inthisexperimentalinvestigation,ahybridofcarbon/E-glasswithvinyl-esterresincompositesjacketwasdesignedtoreinforceatypicalbuildingcomponents,namelyacolumn–beamconnection.StatictestswerethenconductedonFRPreinforcedandnon-reinforcedspecimenswithextensiveinstrumentationtostudytheinfluenceofthedesignedcompositereinforcement.

TheinvestigationreportedinthepaperformspartofacollaborativeresearchprogrambetweentheUniversityofTechnology,SydneyandtheCentreforAdvancedMaterialsTechnology,theUniversityofSydneyinrelationtoapplicationofadvancedfibrecompositestostrengthen,stiffenandhencerehabilitateconcretestructures.

2.Experimentalprocedures

Threeprototypesizereinforcedconcreteframespecimens,representingtypicalconcretecolumn–beamconnection,weredesignedforthisstudy.GeometryofthespecimenswithlocationofFRPcompositereinforcementisillustratedinFig.1.Amongthreespecimens,twoofthemareas-isconcretebeam–columnconnectiontype（nonecomposites-reinforced（Non-CR）specimens）andonespecimenwasreinforcedbythehybridofcarbonfiberandglassfibrecompositesaroundthecolumn–beamjoint（composites-reinforced（CR）specimen）.Allthreespecimenswerepre-castusingstandardcommercialmixgrade40concrete.ThesteelreinforcementoftheconcretespecimensarealsoshowninFig.1.ConcretecompressiontestsbasedontheAustralianStandard（AS1012–1986）wereconductedonthesamplestakenduringtheconcretepourinordertodeterminethemodulusofelasticityandultimatecompressionstrength（UCS）oftheconcrete.

2.1.Compositesarchitecture

Oneofthethreeconcreteframespecimenswasreinforcedwithhybridcomposites.Thehybridcompositesconsistsoffourbasicarchitectures,namelyE-glasswovenroving（WR/600g/m2）,choppedstrandmat（CSM-300g/m2）,carboncloth（plainweave-200g/m2）andglassfibretape（GFT-250g/mm2）.ThedetailsofthecompositesarchitectureareshowninTable1andFig.2.Detailsoflay-upareillustratedinFig.3.WRandcarbonclothareamulti-directionalreinforcementwithbiaxialplainweavingwhichprovideequivalentstrengthinbothaxialandhoopdirections.Theyplaythebasicreinforcementroleinthiscompositesarchitecture.GFTapplyingathoopdirectionprovidesverygoodconfinementandenhancesstructuralintegrity.Theselectionofresincuringsystemsismainlyconcernedwiththeresingel-timeatambienttemperature,whichiscriticaltowrappingprocess.Ingeneral,coldsettingresinsystems（ambienttemperaturecuring）canbeusedwhenwetlay-upprocessisapplied.Sincenolay-upmachineisavailableforthewrappingprocessdescribedinthisstudy,thehandlay-upmethodwasused.Thevinyl-esterresin,Dastar-R/VERPVE/SW/TP,wasmixedwith1.5%ofMEKP（methyl-ethyl-ketone-peroxide）,0.4%ofCoNap（Cobaltnapthenate）,and0.5%ofDMA（Dimethylaniline）atambienttemperature.Theresincuresatambienttemperature.Theweightratiobetweenresinandfibrelayerswas1:

1.5forWR/CSMlayersand1:

0.8forcarboncloth,respectively.Theconcreteframewaswrappedbyalames-woolrollerandaconsolidatingroller.Beforelayingthefirstfibrelayer,theconcretesurfaceswerecleanedupusingacetone,andathinresincoatwasappliedtosealmicroholesonthesurfaceofconcretecolumns.However,furthersurfacetreatmentsuchassandingsurfacetoexposetheaggregateswasintentionallyavoided.Eachcompositelayerwaswettedwiththeresinandrolledontotheconcreteframetoensurefullconsolidation.

Table1.Detailsoffivecompositesystemswithacompositearchitectures

2.2.Designofstatictests

Thestatictestsoftheconcreteframespecimensweresetupinahorizontalplane.Thethreesupportsoftheconcreteframe（noloadapplied）wererollertypeasshowninFig.4.Theendatwhichloadwasappliedwasalsoarollertypesupport,however,horizontalmovementswereobviouslynotprevented.Inordertoprovidetheidealrollertypeboundaryconditionsateachendasdesigned,aspecialsetupwasdevelopedwithcombinationofrollersandaswivelheadateachsupporting/loadingpoint（Fig.5）.Four1000-kN-hydraulicjackswereusedinthetests.Amongthem,theonlyactivejackwasthejackthatappliedloads,whileothersweresimplyactingasadjustablepackingtoprovidingthereactions.

Fig.4.Illustrativesketchoftestset-upforstatictest.

Fig.5.Set-upforstatictestofconcreteframe.

2.3.Instrumentationanddatalogging

Appliedloadaswellasreactionforcesweremeasuredusingfour998.8kNloadcellslocatedineachoffoursupporting/loadingpositions.Inordertoobtaindetailedflexuraldeflectioncurvesfortheconcreteframespecimens,twelvelinearvariabledisplacementtransducers（LVDTs）witharangefrom±2.5to±50mmwereusedatstrategiclocationstomeasuretheflexuraldeflections.ExtensivestraingaugingwasdesignedtocapturethestressdistributionofthetestingspecimensinordertovalidatetestsandgainaninsightintothebehaviouroftheconcreteframewithorwithoutFRPreinforcement.Thetotalnumberofstraingauges