土木工程专业毕业设计外文文献及翻译

-1-英文原文：RehabilitationofrectangularsimplysupportedRCbeamswithsheardeficienciesusingCFRPcompositesAhmedKhalifaa,*,AntonioNannibaDepartmentofStructuralEngineering,UniversityofAlexandria,Alexandria21544,EgyptbDepartmentofCivilEngineering,UniversityofMissouriatRolla,Rolla,MO65409,USAReceived28April1999;receivedinrevisedform30October2001;accepted10January2002AbstractThepresentstudyexaminestheshearperformanceandmodesoffailureofrectangularsimplysupportedreinforcedconcrete(RC)beamsdesignedwithsheardeficiencies.Thesememberswerestrengthenedwithexternallybondedcarbonfiberreinforcedpolymer(CFRP)sheetsandevaluatedinthelaboratory.Theexperimentalprogramconsistedoftwelvefull-scaleRCbeamstestedtofailinshear.Thevariablesinvestigatedwithinthisprogramincludedsteelstirrups,andtheshearspan-to-effectivedepthratio,aswellasamountanddistributionofCFRP.TheexperimentalresultsindicatedthatthecontributionofexternallybondedCFRPtotheshearcapacitywassignificant.Theshearcapacitywasalsoshowntobedependentuponthevariablesinvestigated.Testresultswereusedtovalidateasheardesignapproach,whichshowedconservativeandacceptablepredictions.○C2002ElsevierScienceLtd.Allrightsreserved.Keywords:Rehabilitation;Shear;Carbonfiberreinforcedpolymer1.IntroductionFiberreinforcedpolymer(FRP)compositesystems,composedoffibersembeddedinapolymericmatrix,canbeusedforshearstrengtheningofreinforcedcon-crete(RC)members[1–7].ManyexistingRCbeamsaredeficientandinneedofstrengthening.TheshearfailureofanRCbeamisclearlydifferentfromitsflexuralfailure.Inshear,thebeamfailssuddenlywithoutsufficientwarninganddiagonalshearcracksareconsid-erablywiderthantheflexuralcracks[8].Theobjectivesofthisprogramwereto:1.InvestigateperformanceandmodeoffailureofsimplysupportedrectangularRCbeamswithsheardeficien-ciesafterstrengtheningwithexternallybondedCFRPsheets.2.Addressthefactorsthatinfluenceshearcapacityofstrengthenedbeamssuchas:-2-steelstirrups,shearspan-to-effectivedepthratio(a/dratio),andamountanddistributionofCFRP.3.Increasetheexperimentaldatabaseonshearstrength-eningwithexternallybondedFRPreinforcement.4.Validatethedesignapproachpreviouslyproposedbytheauthors[9].Fortheseobjectives,12full-scale,RCbeamsdesignedtofailinshearwerestrengthenedwithdifferentCFRPschemes.Thesemembersweretestedassimplebeamsusingafour-pointloadingconfigurationwithtwodifferenta/dratios.2.Experimentalprogram2.1.TestspecimensandmaterialsTwelvefull-scalebeamspecimenswithatotalspanof3050mm.andarectangularcross-sectionof150-mm-wideand305-mm-deepweretested.ThespecimensweregroupedintotwomainseriesdesignatedSWandSOdependingonthepresenceofsteelstirrupsintheshearspanofinterest.SeriesSWconsistedoffourspecimens.ThedetailsanddimensionsofthespecimensdesignatedseriesSWareillustratedinFig.1a.Inthisseries,four32-mmsteelbarswereusedaslongitudinalreinforcementwithtwoattopandtwoatbottomfaceofthecross-sectiontoinduceashearfailure.Thespecimenswerereinforcedwith10-mmsteelstirrupsthroughouttheirentirespan.Thestirrupsspacingintheshearspanofinterest,righthalf,wasselectedtoallowfailureinthatspan.SeriesSOconsistedofeightbeamspecimens,whichhadthesamecross-sectiondimensionandlongitudinalsteelreinforcementasforseriesSW.Nostirrupswereprovidedinthetesthalfspanasillustrated.Eachmainseries(i.e.seriesSWandSO)wassubdividedintotwosubgroupsaccordingtoshearspan-to-effectivedepthratio.Thiswasselectedtobea/d=3and4,resultinginthefollowingfoursubgroups:SW3;SW4;SO3;andSO4.ThemechanicalpropertiesofthematerialsusedformanufacturingthetestspecimensarelistedinTable1.FabricationofthespecimensincludingsurfacepreparationandCFRPinstallationisdescribedelsewhere[10].2.2.StrengtheningschemesOnespecimenfromeachseries(SW3-1,SW4-1,SO3-1andSO4-1)wasleftwithoutstrengtheningasacontrolspecimen,whereaseightbeamspecimenswerestrengthenedwithexternallybondedCFRPsheetsfollowingthreedifferentschemesasillustratedinFig.2.-3-InseriesSW3,specimenSW3-2wasstrengthenedwithtwoCFRPplieshavingperpendicularfiberdirections(90°/0°).ThefirstplywasattachedintheformofcontinuousU-wrapwiththefiberdirectionorientedperpendiculartothelongitudinalaxisofthespecimen(90°).Thesecondplywasbondedonthetwosidesofthespecimenwiththefiberdirectionparalleltothebeamaxis（0°）.Thisply[i.e.0°ply]wasselectedtoinvestigatetheimpactofadditionalhorizontalrestraintonshearstrength.InseriesSW4,specimenSW4-2wasstrengthenedwithtwoCFRPplieshavingperpendicularfiberdirection(90°/0°)asforspecimenSW3-2.FourbeamspecimenswerestrengthenedinseriesSO3.SpecimenSO3-2wasstrengthenedwithone-plyCFRPstripsintheformofU-wrapwith90°-fiberorientation.Thestripwidthwas50mmwithcenter-to-centerspacingof125mm.SpecimenSO3-3wasstrengthenedinamannersimilartothatofspecimenSO3-2,butwithstripwidthequalto75mm.SpecimenSO3-4wasstrengthenedwithone-plycontinuousU-wrap(90°).SpecimenSO3-5wasstrengthenedwithtwoCFRPplies(90°/0°)similartospecimensSW3-2andSW4-2.InseriesSO4,twobeamspecimenswerestrengthened.SpecimenSO4-2wasstrengthenedwithone-plyCFRPstripsintheformofU-wrapsimilartospecimenSO3-2.SpecimenSO4-3wasstrengthenedwithone-plycontinuousU-wrap(90°)similartoSO3-4.2.3.Testset