会员注册 | 登录 | 微信快捷登录 QQ登录 微博登录 | 帮助中心 人人文库renrendoc.com美如初恋!
站内搜索 百度文库

热门搜索: 直缝焊接机 矿井提升机 循环球式转向器图纸 机器人手爪发展史 管道机器人dwg 动平衡试验台设计

外文翻译--应用新型延性纤维增强聚合物对混凝土梁的加固 英文版.pdf外文翻译--应用新型延性纤维增强聚合物对混凝土梁的加固 英文版.pdf -- 5 元

宽屏显示 收藏 分享

资源预览需要最新版本的Flash Player支持。
您尚未安装或版本过低,建议您

692ACIStructuralJournal/SeptemberOctober2002ACIStructuralJournal,V.99,No.5,SeptemberOctober2002.MSNo.01349receivedOctober23,2001,andreviewedunderInstitutepublicationpolicies.Copyright©2002,AmericanConcreteInstitute.Allrightsreserved,includingthemakingofcopiesunlesspermissionisobtainedfromthecopyrightproprietors.PertinentdiscussionwillbepublishedintheJulyAugust2003ACIStructuralJournalifreceivedbyMarch1,2003.ACISTRUCTURALJOURNALTECHNICALPAPERAninnovative,uniaxialductilefiberreinforcedpolymerFRPfabrichasbeenresearched,developed,andmanufacturedintheStructuralTestingCenteratLawrenceTechnologicalUniversityforstrengtheningstructures.Thefabricisahybridoftwotypesofcarbonfibersandonetypeofglassfiber,andhasbeendesignedtoprovideapseudoductilebehaviorwithalowyieldequivalentstrainvalueintension.Theeffectivenessandductilityofthedevelopedfabrichasbeeninvestigatedbystrengtheningandtestingeightconcretebeamsunderflexuralload.Similarbeamsstrengthenedwithcurrentlyavailableuniaxialcarbonfibersheets,fabrics,andplateswerealsotestedtocomparetheirbehaviorwiththosestrengthenedwiththedevelopedfabric.Thefabrichasbeendesignedsothatithasthepotentialtoyieldsimultaneouslywiththesteelreinforcementofstrengthenedbeamsandhence,aductileplateausimilartothatforthenonstrengthenedbeamscanbeachieved.Thebeamsstrengthenedwiththedevelopedfabricexhibitedhigheryieldloadsandachievedhigherductilityindexesthanthosestrengthenedwiththecurrentlyavailablecarbonfiberstrengtheningsystems.Thedevelopedfabricshowsamoreeffectivecontributiontothestrengtheningmechanism.Keywordsconcreteductilityfiberreinforcementflexure.INTRODUCTIONTheuseofexternallybondedfiberreinforcedpolymerFRPsheetsandstripshasrecentlybeenestablishedasaneffectivetoolforrehabilitatingandstrengtheningreinforcedconcretestructures.SeveralexperimentalinvestigationshavebeenreportedonthebehaviorofconcretebeamsstrengthenedforflexureusingexternallybondedFRPplates,sheets,orfabrics.SaadatmaneshandEhsani1991examinedthebehaviorofconcretebeamsstrengthenedforflexureusingglassfiberreinforcedpolymerGFRPplates.Ritchieetal.1991testedreinforcedconcretebeamsstrengthenedforflexureusingGFRP,carbonfiberreinforcedpolymerCFRP,andG/CFRPplates.Graceetal.1999andTriantafillou1992studiedthebehaviorofreinforcedconcretebeamsstrengthenedforflexureusingCFRPsheets.Norris,Saadatmanesh,andEhsani1997investigatedthebehaviorofconcretebeamsstrengthenedusingCFRPunidirectionalsheetsandCFRPwovenfabrics.Inalloftheseinvestigations,thestrengthenedbeamsshowedhigherultimateloadscomparedtothenonstrengthenedones.Oneofthedrawbacksexperiencedbymostofthesestrengthenedbeamswasaconsiderablelossinbeamductility.Anexaminationoftheloaddeflectionbehaviorofthebeams,however,showedthatthemajorityofthegainedincreaseinloadwasexperiencedaftertheyieldofthesteelreinforcement.Inotherwords,asignificantincreaseinultimateloadwasexperiencedwithoutmuchincreaseinyieldload.Hence,asignificantincreaseinservicelevelloadscouldhardlybegained.Apartfromtheconditionoftheconcreteelementbeforestrengthening,thesteelreinforcementcontributessignificantlytotheflexuralresponseofthestrengthenedbeam.Unfortunately,availableFRPstrengtheningmaterialshaveabehaviorthatisdifferentfromsteel.AlthoughFRPmaterialshavehighstrengths,mostofthemstretchtorelativelyhighstrainvaluesbeforeprovidingtheirfullstrength.BecausesteelhasarelativelylowyieldstrainvaluewhencomparedwiththeultimatestrainsofmostoftheFRPmaterials,thecontributionofboththesteelandthestrengtheningFRPmaterialsdifferwiththedeformationofthestrengthenedelement.Asaresult,steelreinforcementmayyieldbeforethestrengthenedelementgainsanymeasurableloadincrease.SomedesignersplaceagreaterFRPcrosssection,whichgenerallyincreasesthecostofthestrengthening,toprovideameasurablecontribution,evenwhendeformationsarelimitedbeforetheyieldofsteel.Debondingofthestrengtheningmaterialfromthesurfaceoftheconcrete,however,ismorelikelytohappeninthesecasesduetohigherstressconcentrations.Debondingisoneofthenondesiredbrittlefailuresinvolvedwiththistechniqueofstrengthening.Althoughusingsomespeciallowstrainfiberssuchasultrahighmoduluscarbonfibersmayappeartobeasolution,itwouldresultinbrittlefailuresduetothefailureoffibers.TheobjectiveofthispaperistointroduceanewpseudoductileFRPfabricthathasalowstrainatyieldsothatithasthepotentialtoyieldsimultaneouslywiththesteelreinforcement,yetprovidethedesiredstrengtheninglevel.RESEARCHSIGNIFICANCEFRPshavebeenincreasinglyusedasmaterialsforrehabilitatingandstrengtheningreinforcedconcretestructures.CurrentlyavailableFRPmaterials,however,lacktheductilityandhavedissimilarbehaviorstosteelreinforcement.Asaresult,thestrengthenedbeamsmayexhibitareducedductility,lackthedesiredstrengtheninglevel,orboth.ThisstudypresentsaninnovativepseudoductileFRPstrengtheningfabric.ThefabricprovidesmeasurablyhigheryieldloadsforthestrengthenedbeamsandhelpstoavoidthelossofductilitythatiscommonwiththeuseofcurrentlyavailableFRP.DEVELOPMENTOFHYBRIDFABRICToovercomethedrawbacksmentionedpreviously,aductileFRPmaterialwithlowyieldstrainvalueisneeded.Titleno.99S71StrengtheningofConcreteBeamsUsingInnovativeDuctileFiberReinforcedPolymerFabricbyNabilF.Grace,GeorgeAbdelSayed,andWaelF.Ragheb693ACIStructuralJournal/SeptemberOctober2002LiteraturereviewonhybridizationTodevelopthismaterial,hybridizationfordifferentfiberswasconsidered.Hybridizationofmorethanonetypeoffibrousmaterialswastheinterestofmanymaterialsscienceresearchers.Mostoftheirworkwasconcernedwithcombiningtwotypesoffiberstoenhancethemechanicalpropertiesofeithertypeactingaloneandtoreducethecost.ThishasbeenreportedinseveralpublicationssuchasBunsellandHarris1974,Philips1976,MandersandBader1981,ChowandKelly1980,andFukudaandChow1981.HybridizationinterestedstructuralengineersasatooltoovercometheproblemofalackofductilityinFRPreinforcingbars.Nanni,Henneke,andOkamoto1994studiedbarsofbraidedaramidfibersaroundasteelcore.TamuzsandTepfers1995reportedexperimentalinvestigationsforhybridfiberbarsusingdifferentcombinationsofcarbonandaramidfibers.Somboonsong,Frank,andHarris1998developedahybridFRPreinforcingbarusingbraidedaramidfibersaroundacarbonfibercore.Harris,Somboonsong,andFrank1998usedthesebarsinreinforcingconcretebeamstoachievethegeneralloaddeflectionbehaviorofconcretebeamsreinforcedwithconventionalsteel.DesignconceptandmaterialsTogenerateductility,ahybridizationtechniqueofdifferenttypesoffibershasbeenimplemented.Threefibershavebeenselectedwithadifferentmagnitudeofelongationsatfailure.Figure1showsthestressstraincurvesintensionfortheselectedcompositefibers,andTable1showstheirmechanicalproperties.Thetechniqueisbasedoncombiningthesefiberstogetherandcontrollingthemixtureratiosothatwhentheyareloadedtogetherintension,thefiberswiththelowestelongationLEfailfirst,allowingastrainrelaxationanincreaseinstrainwithoutanincreaseinloadforthehybrid.TheremaininghighelongationHEfibersareproportionedtosustainthetotalloaduptofailure.ThestrainvalueatfailureoftheLEfiberspresentsthevalueoftheyieldequivalentstrainofthehybrid,whiletheHEfiberstrainatfailurepresentsthevalueofultimatestrain.TheloadcorrespondingtofailureofLEfiberspresentstheyieldequivalentloadvalue,andthemaximumloadcarriedbytheHEfibersistheultimateloadvalue.UltrahighmoduluscarbonfibersCarbonNo.1havebeenusedasLEfiberstohaveaslowastrainaspossible,butnotlessthantheyieldstrainofsteelapproximately0.2forGrade60steel.Ontheotherhand,EglassfiberswereusedasHEfiberstoprovideashighastrainaspossibletoproduceahighductilityindextheratiobetweendeformationatfailureanddeformationatyield.HighmoduluscarbonfibersCarbonNo.2wereselectedasmediumelongationMEfiberstominimizethepossibleloaddropduringthestrainrelaxationthatoccursafterfailureoftheLEfibers,andalsotoprovideagradualloadtransitionfromtheLEfiberstotheHEfibers.Basedonthisconcept,auniaxialfabricwasfabricatedandtestedtocompareitsbehaviorintensionwiththetheoreticalpredictedloadingbehavior.Thetheoreticalbehaviorisbasedontheruleofmixtures,inwhichtheaxialstiffnessofthehybridiscalculatedbyasummationoftherelativestiffnessofeachofitscomponents.Thefabricwasmanufacturedbycombiningdifferentfibersasadjacentyarnsandimpregnatingtheminsideamoldbyanepoxyresin.Figure2showsaphotoofoneofthefabricatedsamples.Wovenglassfibertabswereprovidedatbothendsofthetestcouponstoeliminatestressconcentrationsatendfixturesduringtesting.Thecouponshadathicknessof2mm0.08in.andawidthof25.4mmACImemberNabilF.GraceisaprofessorandChairoftheStructuralTestingCenter,DepartmentofCivilEngineering,LawrenceTechnologicalUniversity,Southfield,Mich.HeisamemberofACICommittee440,FiberReinforcedPolymerReinforcementandJointACIASCECommittee343,ConcreteBridgeDesign.Hisresearchinterestsincludetheuseoffiberreinforcedpolymerinreinforcedandprestressedconcretestructures.GeorgeAbdelSayedisProfessorEmeritusintheDepartmentofCivilandEnvironmentalEngineering,UniversityofWindsor,Windsor,Ontario,Canada.Hisresearchinterestsincludesoilstructureinteraction.WaelF.RaghebisaresearchassistantintheDepartmentofCivilEngineeringatLawrenceTechnologicalUniversity.HeisaPhDcandidateintheDepartmentofCivilandEnvironmentalEngineering,UniversityofWindsor,Windsor,Ontario,Canada.Fig.1Stressstrainbehaviorofcompositefibersandsteelreinforcingbars.Compositepropertiesarebasedon60fibervolumefraction.Table1MechanicalpropertiesofcompositefibersFibermaterialDescriptionModulusofelasticity,GPaMsiTensilestrength,MPaksiFailurestrain,CarbonNo.1Ultrahighmoduluscarbonfibers3795513241920.35CarbonNo.2Highmoduluscarbonfibers23133.524133500.9to1.0GlassEglassfibers48710341502.1Fig.2Testsamplefordevelopeduniaxialhybridfabric.Fig.3Resultsoftensiletestsfordevelopedhybridfabric.694ACIStructuralJournal/SeptemberOctober20021in.andweretestedintensionaccordingtoASTMD3039specifications.TheaverageloadstraincurveforfourtestedsamplesisshowninFig.3togetherwiththetheoreticalprediction.Itshouldbenotedthatthebehaviorislinearuptoastrainof0.35,whentheLEfibersstartedtofail.Atthispoint,thestrainincreasedatafasterratethantheload.Whenthestrainreached0.90,theMEfibersstartedtofail,resultinginanadditionalincreaseinstrainwithoutasignificantincreaseinload,uptothetotalfailureofthecouponbyfailureoftheHEfibers.Ayieldequivalentloadthefirstpointontheloadstraincurvewherethebehaviorbecomesnonlinearof0.46kN/mmwidth2.6kips/in.andanultimateloadof0.78kN/mm4.4kips/in.areobserved.BEAMTESTSBeamdetailsThirteenreinforcedconcretebeamswithcrosssectionaldimensionsof152x254mm6x10in.andlengthsof2744mm108in.werecast.TheflexurereinforcementofthebeamsconsistedoftwoNo.516mmtensionbarsnearthebottom,andtwoNo.39.5mmcompressionbarsnearthetop.Toavoidshearfailure,thebeamswereoverreinforcedforshearwithNo.39.5mmclosedstirrupsspacedat102mm4.0in..Fivebeamswereformedwithroundedcornersof25mm1in.radiustofacilitatetheinstallationofthestrengtheningmaterialontheirsidesandbottomfaceswithoutstressconcentrations.Figure4showsthebeamdimensions,reinforcementdetails,supportlocations,andlocationofloadingpoints.ThesteelusedwasGrade60withayieldstrengthof415MPa60,000psi,whiletheconcretecompressivestrengthatthetimeoftestingthebeamswas55.2MPa8000psi.StrengtheningmaterialsThedevelopedhybridfabricwasusedtostrengtheneightbeams.Twodifferentthicknessesoffabricwereused.ThefirstHsystem,t1.0mmhadathicknessof1.0mm0.04in.,andthesecondHsystem,t1.5mmhadathicknessof1.5mm0.06in..Fourotherbeamswerestrengthenedwiththreecurrentlyavailablecarbonfiberstrengtheningmaterials1auniaxialcarbonfibersheetwithanultimateloadof0.34kN/mm1.95kips/in.2twolayersofauniaxialcarbonfiberfabricwithanultimateloadof1.31kN/mm7.5kips/in.forthetwolayerscombinedand3apultrudedcarbonfiberplatewithanultimateloadof2.8kN/mm16kips/in..ThetestedloadstraindiagramsforFig.4Detailsoftestbeams.Fig.5Comparisonbetweencarbonfiberplate,fabric,sheet,anddevelopedhybridfabricHSystem.ACIStructuralJournal/SeptemberOctober2002695allthesematerialsareshowninFig.5.Table2showsthepropertiesofthestrengtheningmaterials,includingthedevelopedfabric.AdhesivesForthehybridfabric,anepoxyresinEpoxyAwasusedtoimpregnatethefibersandasanadhesivebetweenthefabricandtheconcretesurface.Thisepoxyhadanultimatestrainof4.4toensurethatitwouldnotfailbeforethefailureofthefibers.Forthebeamsstrengthenedwithcarbonfibersheets,plates,andfabric,anepoxyresinwithanultimatestrainof2.0wasusedEpoxyB.ThemechanicalpropertiesoftheadhesivesprovidedbytheirmanufacturesareshowninTable3.StrengtheningThebeambottomfacesandsidesweresandblastedtoroughenthesurface.Thebeamswerethencleanedwithacetonetoremovedirt.Twostrengtheningconfigurationswereused1strengtheningmaterialonthebottomfaceofthebeamonlyBeamGroupAand2strengtheningmaterialonthebottomfaceandextendedup152mm6in.onbothsidestocoverapproximatelyalltheflexuraltensionportionsofthebeamBeamGroupB.Thestrengtheningwasinstalledfor2.24m88in.,centeredalongthelengthofthebeam.Theepoxywasallowedtocureforatleast2weeksbeforethebeamsweretested.ForthebeamsstrengthenedwiththedevelopedhybridfabricHsystem,twobeamswerefabricatedandtestedforeachconfigurationtoverifytheresults.Table4summarizesthetestbeams.InstrumentationTheFRPstrainatmidspanwasmeasuredbythreestraingageslocatedatthebottomfaceofthebeam.ThesteeltensilestrainwasmeasuredbymonitoringthestrainonthesidesurfaceofthebeamatreinforcingbarlevelusingaDEMECdetachablemechanicalgagewithgagepointsforBeamGroupA,whilestraingageswereusedforBeamGroupB.Themidspandeflectionwasmeasuredusingastringpotentiometer.Thebeamswereloadedusingahydraulicactuator.Theloadwasmeasuredbymeansofaloadcell.Allthesensorswereconnectedtoadataacquisitionsystemtoscanandrecordthereadings.TESTRESULTSANDDISCUSSIONControlbeamThecontrolbeamhadayieldloadof82.3kN18.5kipsandanultimateloadof95.7kN21.5kips.Thebeamfailedbytheyieldingofsteel,followedbycompressionfailureofconcreteatthemidspan.TestresultsforthecontrolbeamareshowninthefiguresofthetestresultsofthestrengthenedbeamsFig.6through15.BeamGroupABeamGroupAcontainsthebeamsstrengthenedatthebottomfaceonly.Figure6to11showthetestresultsforthesebeams.TheresultsofBeamsH501andH751wereCommerciallyavailable.†Developedductilehybridsystem.Table2PropertiesofstrengtheningmaterialsTypeYieldequivalentload,kN/mmkips/in.Yieldequivalentstrain,Ultimateload,kN/mmkips/in.Ultimatestrain,Thickness,mmin.Carbonfibersheet0.341.951.20.130.005Carbonfiberplate2.816.01.41.30.05Carbonfiberfabric1.317.501.41.900.075Hsystem†t1mm0.231.300.350.392.241.741.00.04Hsystem†t1.5mm0.341.950.350.593.361.741.50.06Table3PropertiesofepoxyadhesivesEpoxytypeTensilestrength,MPaksiUltimatestrain,Compressivestrength,MPaksiA66.39.624.4109.215.84B68.910.02.086.212.50Fig.6BehaviorofBeamC1.Table4SummaryoftestbeamsBeamgroupBeamdesignationStrengtheningmaterialN/AControlN/AGroupAC1CarbonfibersheetC2CarbonfiberplateC3CarbonfiberfabricH501Hsystemt1mmH502H751Hsystemt1.5mmH752GroupBCSCarbonfibersheetHS501Hsystemt1mmHS502HS751Hsystemt1.5mmHS752
编号:201311171140195976    大小:520.24KB    格式:PDF    上传时间:2013-11-17
  【编辑】
5
关 键 词:
教育专区 外文翻译 精品文档 外文翻译
温馨提示:
1: 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
2: 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
3.本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
5. 人人文库网仅提供交流平台,并不能对任何下载内容负责。
6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。
  人人文库网所有资源均是用户自行上传分享,仅供网友学习交流,未经上传用户书面授权,请勿作他用。
0条评论

还可以输入200字符

暂无评论,赶快抢占沙发吧。

当前资源信息

4.0
 
(2人评价)
浏览:25次
英文资料库上传于2013-11-17

官方联系方式

客服手机:13961746681   
2:不支持迅雷下载,请使用浏览器下载   
3:不支持QQ浏览器下载,请用其他浏览器   
4:下载后的文档和图纸-无水印   
5:文档经过压缩,下载后原文更清晰   

相关资源

相关资源

相关搜索

教育专区   外文翻译   精品文档   外文翻译  
关于我们 - 网站声明 - 网站地图 - 友情链接 - 网站客服客服 - 联系我们
copyright@ 2015-2017 人人文库网网站版权所有
苏ICP备12009002号-5