土木工程专业毕业设计外文文献及翻译.doc

土木工程专业毕业设计外文文献及翻译.doc

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山东建筑大学毕业设计外文文献及译文

英文原文：

RehabilitationofrectangularsimplysupportedRCbeamswithsheardeficienciesusingCFRPcomposites

AhmedKhalifaa,*,AntonioNannib

aDepartmentofStructuralEngineering,UniversityofAlexandria,Alexandria21544,Egypt

bDepartmentofCivilEngineering,UniversityofMissouriatRolla,Rolla,MO65409,USA

Received28April1999;receivedinrevisedform30October2001;accepted10January2002

Abstract

Thepresentstudyexaminestheshearperformanceandmodesoffailureofrectangularsimplysupportedreinforcedconcrete（RC）beamsdesignedwithsheardeficiencies.Thesememberswerestrengthenedwithexternallybondedcarbonfiberreinforcedpolymer（CFRP）sheetsandevaluatedinthelaboratory.Theexperimentalprogramconsistedoftwelvefull-scaleRCbeamstestedtofailinshear.Thevariablesinvestigatedwithinthisprogramincludedsteelstirrups,andtheshearspan-to-effectivedepthratio,aswellasamountanddistributionofCFRP.TheexperimentalresultsindicatedthatthecontributionofexternallybondedCFRPtotheshearcapacitywassignificant.Theshearcapacitywasalsoshowntobedependentuponthevariablesinvestigated.Testresultswereusedtovalidateasheardesignapproach,whichshowedconservativeandacceptablepredictions.2002ElsevierScienceLtd.Allrightsreserved.

Keywords:

Rehabilitation;Shear;Carbonfiberreinforcedpolymer

1.Introduction

Fiberreinforcedpolymer（FRP）compositesystems,composedoffibersembeddedinapolymericmatrix,canbeusedforshearstrengtheningofreinforcedcon-crete（RC）members[1–7].ManyexistingRCbeamsaredeficientandinneedofstrengthening.TheshearfailureofanRCbeamisclearlydifferentfromitsflexuralfailure.Inshear,thebeamfailssuddenlywithoutsufficientwarninganddiagonalshearcracksareconsid-erablywiderthantheflexuralcracks[8].

Theobjectivesofthisprogramwereto:

1.InvestigateperformanceandmodeoffailureofsimplysupportedrectangularRCbeamswithsheardeficien-ciesafterstrengtheningwithexternallybondedCFRPsheets.

2.Addressthefactorsthatinfluenceshearcapacityofstrengthenedbeamssuchas:

steelstirrups,shearspan-to-effectivedepthratio（a/dratio）,andamountanddistributionofCFRP.

3.Increasetheexperimentaldatabaseonshearstrength-eningwithexternallybondedFRPreinforcement.

4.Validatethedesignapproachpreviouslyproposedbytheauthors[9].

Fortheseobjectives,12full-scale,RCbeamsdesignedtofailinshearwerestrengthenedwithdifferentCFRPschemes.Thesemembersweretestedassimplebeamsusingafour-pointloadingconfigurationwithtwodifferenta/dratios.

2.Experimentalprogram

2.1.Testspecimensandmaterials

Twelvefull-scalebeamspecimenswithatotalspanof3050mm.andarectangularcross-sectionof150-mm-wideand305-mm-deepweretested.ThespecimensweregroupedintotwomainseriesdesignatedSWandSOdependingonthepresenceofsteelstirrupsintheshearspanofinterest.

SeriesSWconsistedoffourspecimens.ThedetailsanddimensionsofthespecimensdesignatedseriesSWareillustratedinFig.1a.Inthisseries,four32-mmsteelbarswereusedaslongitudinalreinforcementwithtwoattopandtwoatbottomfaceofthecross-sectiontoinduceashearfailure.Thespecimenswerereinforcedwith10-mmsteelstirrupsthroughouttheirentirespan.Thestirrupsspacingintheshearspanofinterest,righthalf,wasselectedtoallowfailureinthatspan.

SeriesSOconsistedofeightbeamspecimens,whichhadthesamecross-sectiondimensionandlongitudinalsteelreinforcementasforseriesSW.NostirrupswereprovidedinthetesthalfspanasillustratedinFig.1b.

Eachmainseries（i.e.seriesSWandSO）wassubdividedintotwosubgroupsaccordingtoshearspan-to-effectivedepthratio.Thiswasselectedtobea/d=3and4,resultinginthefollowingfoursubgroups:

SW3;SW4;SO3;andSO4.

ThemechanicalpropertiesofthematerialsusedformanufacturingthetestspecimensarelistedinTable1.FabricationofthespecimensincludingsurfacepreparationandCFRPinstallationisdescribedelsewhere[10].

Table1

2.2.Strengtheningschemes

Onespecimenfromeachseries（SW3-1,SW4-1,SO3-1andSO4-1）wasleftwithoutstrengtheningasacontrolspecimen,whereaseightbeamspecimenswerestrengthenedwithexternallybondedCFRPsheetsfollowingthreedifferentschemesasillustratedinFig.2.

InseriesSW3,specimenSW3-2wasstrengthenedwithtwoCFRPplieshavingperpendicularfiberdirections（90°/0°）.ThefirstplywasattachedintheformofcontinuousU-wrapwiththefiberdirectionorientedperpendiculartothelongitudinalaxisofthespecimen（90°）.Thesecondplywasbondedonthetwosidesofthespecimenwiththefiberdirectionparalleltothebeamaxis（0°）.Thisply[i.e.0°ply]wasselectedtoinvestigatetheimpactofadditionalhorizon