毕业论文翻译材料VIP

毕业论文翻译材料毕业论文翻译材料 翻译材料题目预应力碳纤维布加固钢筋混凝土梁抗弯性能研究出处W eb Miningand Web based Application xx WMWA 09 Second Pacific Asia Conference 目录第一节1Abstract 12英文论文原文部分 1第二节1汉语翻译部分 81第一章Research onDefl ection ofStrengtheni ngConcrete Beamwi thPrestressed CFRPSheets WANGXi angyang JI Shaobo ZHAO Guanghui Schoolof Transportation Wuhan Universityof TechnologyWuhan China 430063Wangxyxx 163 AbstractCFRP sheetshave beenwidely usedin strengtheningconcrete structuresas anew materialand prestressed CFRP sheetscan improvethe carryingcapacity of beams This paperresearched theaffection aboutthe deflectionand rigidityof concretestructures afterstrengthening with prestressed CFRP sheets and derivedrelated theoretic formulas It isshown that the prestressedCFRP sheetscan notdramatically changethe deflection of thestructures becausethe prestressedCFRP sheets are generallythin withsmall moment of inertiafor thestructural sectionsKeywords prestressed strengthening theoreticformula s deflection 21Introduction Carbon fiber reinforcedplastic CFRP sheets whichare characteristicof high strength light weightand anticorrosionare widelyadopted instrengthening but thecapacity of highstrengthin CFRPcan t fullyexert withgeneral strengtheningmethod Prestressed CFRP sheets as shownin Fig 1 can improvethe mechanical behaviors of the membersin usageand beargreat significancein promotingthe researchesof thistechnology andfor theengineering practices Fi gure1Carbonfiberrei nforcedplasti csheets Takingthe currentlywidely usedbox girderbridges as a model this paperderives themethod ofcalculating the deflectionof bridges strengthenedwith prestressedCFRP sheetsand theoreticallyanalyzes themechanicalbehaviorsof thestructures after the strengthening 2Calculation of the deflection2 1Calculation principleWhen strengtheningconcrete beamswithprestressedCFRP sheetsthe ponentsare monlyunder the action ofloads the reinforcedbar have already beenunder sometensile strainand the concrete in the tensile area mayhavealreadyhad cracks The deflectionof thestructures inusage should be calculatedseparately Taking B type prestressedconcrete memberasareference aording toReference 3 3the bendingrigidity is calculated segmentby segmentaording tothe moment of thebination forshort term actioneffects under the action of crackingmoment crMB0 0 95EC I0 1 underthe actionofmoment Ms Mcr Bcr EcIcr 2 The impactsof prestressedCFRP sheetson deflectionmainly liein altering the rigidityof thesection andcausing displacementin the members The deflectionof prestressedconcrete ponentsis posedof twoparts the displacement generated by eentricpretension anddeflection generatedby externalload permanent load and live load For prestressedconcrete membersof prestressedCFRP sheets thedisplacementgeneratedbyCFRP sheets prestress shouldbe considered The deflectionof prestressedCFRP sheetsmainly includesthe followingfour parts 1 Deflection underthe actionof permanentload2 Displacement generatedby prestressed steel bars3 Deflection undertheactionof liveload4 Displacement generatedby prestressedCFRP sheets2 2Deflection underthe permanentand liveload crs McrM MWMdsBoBcr 3 In which M p bending momentcaused by theactionof permanentloadandliveloadat any section x M x bending momentat anysection atvirtual statex I0 converted second moment ofcross sectionafter thestrengthening of CFRP sheets I cr converted secondmoment ofcracking sectionafterthestrengthening ofCFRP sheets 2 3 Displacement generatedby theprestressed steel4Under theprestress of steel strands the moment of inertia of prestressedconcrete membersshould adoptthat of the pretensionstage The displacementis calculatedaording tothe followingformula 0 95Xpec nMMpedsEI 4 In which M pe bending momentcaused byexisting pretensionofsteelstrands at anysection x I n momentof inertiaof the membersat thestage oflongitudinal steelstrands pretension 2 4 Displacement generatedby prestressedCFRP sheetsUnder CFRP sheetsprestress the momentofinertiaof prestressedconcrete membersshould takethe convertedsecondmomentof areaatthestrengthening stage The displacementis calculatedaording tothe followingformula cfecfcrMxMBeds 5 In whichM cfe bending momentcaused byCFRP sheetsexisting pretensionatanysectionx 3 Analysis ofrigidity RigidityB0and Bcr aredecided by0I and Icr The paperis toderive thecalculation methodof prestressedCFRP strengtheningconcrete boxgirders section I0and Icr underthe premisethat the depth of the tensile area iscovered by the web as shownin Fig 2 Aording toReference 5 thememberswork withcracks At the tensileareathe concretefails andtransforms thetension onit tothe longitudinalreinforcement whichat thisstage doesnot yieldand thepressive stressof the concrete takesthe shapeof triangle With the CFRP sheets the sectional area of the steel bar andCFRP sheetsshouldbeconverted intothe concretesectionalareawhich islocated atthe gravitycenter of the steelbar and theCFRP sheets separately 53 1Calculation ofIcr Themomentofinertia Icr of the convertedsection ofcracking sectionfor centralaxis is 3 2 Calculation of0I0I iscalculatedby thesection posedof thecross sectionarea of theconcreteandtheconverted areaof plainreinforced bars prestressed steelstrands andprestressedCFRPsheets In which X the depth of pressionx canbe calculatedbythestatic balancingof the tensilearea the pressionarea andthe neutralaxis b the width of theweb of the I Section h thedepth of theweb of the I Section33221 23221 0 131 b 6ffssppcffssppppfeIcrb xbxhA hxA x aA h axAxa Ahx 01h1 13232 3bhbh 122hf122122222 1 0 1 1 222 1 0 1 hfIxfhffhfxfhffhf hxsAshxsAs xapAphapxpAp hapcfAfehx b b b b b b b b 7 6 fb the effectivewidth ofthe pressedflange ofthe I Section the effectivedepthofthe pressedflange ofthe I Section b f the effectivewidthofthetensileflange ofthe I Section h f the effectivedepthofthetensileflange ofthe I Section s the ratiooftheelastic modulusofthesteelbarto that oftheconcrete p the ratiooftheelastic modulusoftheprestressedsteelstrands to thatoftheconcretecf the ratiooftheelastic modulusoftheCFRPsheetstothatoftheconcrete Aordingto equations 6 and 7 the reinforcementofCFRPsheets changesthe rigidityofthesection ina verylimited way Though CFRPsheets areof highstrength they arequite thinand ofsmall areaand a small sectionmoment inertia Therefore theygenerally havea smallimpact onthe rigidity This iswhy thestrengthening ofCFRPsheetsdoes littlein changingthe rigidityofthestructure inlong span bridges 4 Conclusions Theanalysis aboveshows that The influencesof prestressedCFRPsheetson deflectionmainly liein alteringthe rigidityofthesection andcausing displacementinthemembers For longspanbridges alteringthethickness ofCFRPsheetscan notdramatically amelioratethedeflectionof midspanin bridges This canbe provedbytheway ofFEM though CFRPsheetsareof highstrength they arequite thinand ofsmall areaand asmall sectionmomentofinertia Therefore theygenerally haveasmallimpact onthe rigidity 7References 1 Chinese NationalStandards Concrete StructureDesign Specification GB50367 xx Beijing ChinaArchitecture0I 用碳纤维布加固混凝土后横截面的二次转换弯矩 Icr 用碳纤维布加固混凝土后开裂截面的二次转换弯矩 102 3预应力钢筋产生的位移在钢绞线的预拉力作用下 预应力混凝 土的惯性矩通常应该采用预拉阶段的惯性矩 位移的计算应采用以下公式0 95Xpec nMMpedsEI 4 其中peM 在任意截面由于现存钢绞线的预应力产生的弯矩n I 在纵筋钢绞线预拉阶段构件的惯性矩 2 4预应力碳纤维布作用下产生的位移在预应力碳纤维布作用下 预 应力混凝土的惯性矩应该采用预拉阶段的惯性矩 位移按照下列公式计算 5 其中cefM 在任意截面x由于现存的碳纤维布预应力所产生的弯矩3刚度的分析 刚度0B和Bcr由0I和crI所决定 刚度分析的目的在于推导预应力碳纤维布加固箱梁0I和crI的计算方 法 在受拉区 0I和crI受拉区的深度由腹板传递 如图2所示 按照参考文献 5 构件带裂缝工作 受拉区混凝土破坏并且将拉力 传递给纵筋 在这个阶段钢筋没有屈服受压区混凝土的应力呈三角 形分布 3 1Icr的计算裂缝截面对中心轴的折算偏心距由以下公式来进行计 算 cfecfcrMxMBeds 33221 23221 0 11 b 3 6ffssppcffssppppfeIcrb xbx hAhxAxaA haxA xaA hx 113 2f h 的计算0I要根据组成的混凝土截面和折算钢筋截面 普通钢筋 预应力钢绞线和预应力碳纤维布 来计算 01h1 132323bhbh 122hf122122222 1 0 1 1 222 1 0 1 h