土木工程专业毕业设计外文文献及翻译Word格式文档下载.doc
《土木工程专业毕业设计外文文献及翻译Word格式文档下载.doc》由会员分享,可在线阅读,更多相关《土木工程专业毕业设计外文文献及翻译Word格式文档下载.doc(44页珍藏版)》请在冰豆网上搜索。
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