《土木工程专业英语 第2版》 课件 Unit5 Composite Construction；Unit6 Introduction to Foundation Analysis and Design

Unit5CompositeConstructionEnglishforCivilEngineering——Teacher：Prof.ZhengLu（SchoolofCivilEngineering,TONGJIUNIVERSITY）Unit5CompositeConstruction5.1Overview（概述）5.1.1CompositeSteel-ConcreteBeam（钢-混凝土组合梁）5.1.2CompositeSlabs（组合楼板）5.1.3SteelReinforcedConcrete(SRC)（型钢混凝土）5.1.4ConcreteFilledTube(CFT)Columns（钢管混凝土）5.2Pre-stressedConcreteCompositeSlabs（预应力混凝土组合楼板）5.2.1Introduction（简介）5.2.2OverviewofPre-stressedConcreteCompositePlate（预应力混凝土组合楼板综述）5.2.3TheResearchandApplicationofPre-stressedCompositeSlabs（预应力组合楼板的研究及应用）5.2.4Conclusion（结论）In1988,BankofChinaTowerinHongKong(Fig.5-1)wascompleted.ThismagnificentbuildingwasthetallestbuildinginAsiaatthattime.Thebuildingwasconstructedusingcompositesteel-concretestructures,whichisanimportantmilestonesincethedevelopmentofthecompositeconstruction.中银大厦是组合结构史上的里程碑compositesteel-concretestructures钢-混凝土组合结构；milestone里程碑5.1OverviewCompositeconstructionisamethodofconstructionthatisusedinavarietyofengineeringandbuildingapplications.Employingdissimilarcomponents,suchasconcreteandsteelorfiberglassandfoam,forasingleuseorstructureiscalledcompositeconstruction.Thegoalisunifyingoftheindividualcomponentpropertiestocreateacompositematerialthatpossessesthedesiredpropertiesofallcomponentpieces.组合结构定义dissimilar不同的；fiberglass玻璃纤维；foam泡沫橡胶；unify统一；possess具有5.1OverviewInstructuralengineering,compositeconstructionexistswhentwodifferentmaterialsareboundtogethersostronglythattheyacttogetherasasingleunitfromastructuralpointofview.Whenthisoccurs,itiscalledcompositeaction.Onecommonexampleinvolvessteelbeamssupportingconcretefloorslabs.Ifthebeamisnotconnectedfirmlytotheslab,thentheslabtransfersallofitsweighttothebeamandtheslabcontributesnothingtotheloadcarryingcapabilityofthebeam.However,iftheslabisconnectedpositivelytothebeamwithstuds,thenaportionoftheslabcanbeassumedtoactcompositelywiththebeam.Ineffect,thiscompositecreatesalargerandstrongerbeamthanthesteelbeamalone.Thestructuralengineermaycalculateatransformedsectionasonestepinanalyzingtheloadcarryingcapabilityofthecompositebeam.如何实现组合作用concretefloorslabs混凝土楼板；stud铆钉；beassumedto假定为；stud铆钉5.1OverviewCommonstructuralmembersofcompositeconstructioninclude①Steel-ConcreteCompositeBeams(Steel-ConcreteFloorCompositeStructure),②CompositeSlabs,③SteelReinforcedConcrete:SteelReinforcedBeams,SteelReinforcedColumns,SteelReinforcedWalls,④ConcreteFilledTube.组合结构分类5.1OverviewCompositesteel-concretebeamismadeupofsteelbeamandslabbyshear

connector.Inthistypeofcompositebeam,concreteandsteelbeamhavejointstressandcompatibilityofdeformation,whichmakefulluseofthecompressivestrengthofconcreteandthetensilestrengthofsteel.Soitremarkablyraisesthestiffnessandstabilityofbeams.钢-混凝土组合梁的组合形式shear

connector剪力连接键；joint共同的5.1.1CompositeSteel-ConcreteBeamCompositesteel-concretebeamshavebeendevelopedveryfastinrecentyears,andmoreandmorewidelyusedasthehorizontalelementscarryingheavyloadsinbuildingsandbridges,obtainingnotableeconomicandsocialbenefits.组合结构定义horizontalelements水平构件5.1.1CompositeSteel-ConcreteBeamAdvantagesofcompositebeams:1. Theconcreteandsteelisutilizedeffectively.2. Moreeconomicalsteelsectionisusedincompositeconstructionthanconventionalnon-compositeconstructionforthesamespanandloading.3. Depthandweightofsteelbeamrequiredisreduced.So,theconstructiondepthalsoreducesincreasingtheheadroomofthebuilding.组合梁的优点utilize利用；conventional传统的；headroom净空5.1.1CompositeSteel-ConcreteBeam4. Compositebeamshavehigherstiffness,thustheyhavelessdeflectionthansteelbeams.5. Compositebeams(Fig.5-2)cancoverforlargespacewithouttheneedofanyintermediatecolumns.6. Compositeconstructionisfasterbecauseofusingrolledsteelandpre-fabricatedcomponentsthancast-in-situconcrete.7. Encasedsteelbeamhavehigherresistancetofireandcorrosion.组合梁的优点intermediatecolumns中柱；rolledsteel轧制钢；pre-fabricatedcomponents预制构件；cast-in-situconcrete现浇混凝土；encasedsteelbeam内置钢梁；corrosion腐蚀5.1.1CompositeSteel-ConcreteBeamCompositeslabscommonlyreferstosteeldeckreinforcedcompositeslabs(Fig.5-3)whichareformedbypouringconcreteonthesteelplateofdifferentkindsofconcaveandconvexribsordifferentkindsgrooves.Theyrelyonvariousformsofconcaveandconvexribsorgroovesandthensteelandconcretewillbeconnectedtogether.组合板steeldeck钢板；concaveandconvexribs凹凸肋；groove凹槽5.1.2CompositeSlabsSteelreinforcedconcrete(Fig.5-4)compositestructures(shortastheSRCcompositestructure)ismadeupofprofilesteel,longitudinalreinforcement,stirrupsandconcrete.Thatisconcretestructurewithprofilesteelinthecoreofstructurecomponentsandwithstirrupsandappropriate

verticalreinforcementoutofstructurecomponents.Itisdividedintotwotypesofstructure:allstructurecomponentsaresteelreinforcedconcretecompositestructuresandpartofstructurecomponentsaresteelreinforcedconcretecompositestructures.型钢—钢筋混凝土组合结构的组成成分profilesteel型钢；longitudinalreinforcement纵向钢筋；stirrup箍筋；appropriate适量的；verticalreinforcement竖向钢筋（应为纵向钢筋）；5.1.3SteelReinforcedConcrete(SRC)Concrete-filledtubecolumnsconsistofasteeltubefilledwithconcrete.Theconcretecoreaddsstiffnessandcompressivestrengthtothetubularcolumnandreducesthepotentialforinwardlocalbuckling.Conversely,thesteeltubeactsaslongitudinalandlateralreinforcementfortheconcretecorehelpingittoresisttension,bendingmomentandshearandprovidingconfinementfortheconcrete.钢管混凝土柱的组成及优点inwardlocalbuckling向内的局部屈曲；lateralreinforcement侧向支承；confinement约束5.1.4ConcreteFilledTube(CFT)ColumnsDuetothebenefitofcompositeactionofthetwomaterials,theCFTcolumnsprovideexcellentseismiceventresistantstructuralpropertiessuchashighstrength,highductilityandlargeenergyabsorptioncapacity.Also,circularhollowsectionspossessmanyadvantagesoveropensections,includingaestheticappearanceandeconomyintermsofmaterialcosts.钢管混凝土柱抗震性能好ductility延性；aestheticappearance美观5.1.4ConcreteFilledTube(CFT)ColumnsDuetothecomplexityofconnectionsbetweensteelbeamsandcircularhollowsections,theiruseinstructuralsteelworkislimited.Thisisbecausetheuseofstandardboltingisnotfeasibleandcostlyunpopularweldedconnectionsarethenormalsolutions.Concrete-filledsteeltube(CFT)columnscombinetheadvantagesofductility,generallyassociatedwithsteelstructures,withthestiffnessofaconcretestructuralsystem.钢管混凝土柱同时具有钢结构和混凝土两种材料的优点，不过不能使用常规螺栓进行连接feasible可行的5.1.4ConcreteFilledTube(CFT)ColumnsInallkindsoffloors,concreteslabsoccupythedominantposition.Concreteslabscanbedividedintotwomajorcategories,thecast-in-placeslabandtheprecastslab.Thecast-in-placeslabhasgoodstructuralintegrity,however,itneedson-siteconcretepouringprocedure,largeconcretewetconstruction,instableconstructionquality,morescaffoldingandtemplates,highcostsandlongconstructionperiod.Theprecastslabisproducedinthefactoryandhasadvantagesoflessconcretewetconstruction,stableconstructionquality,lessscaffoldingandtemplates,lowconstructionnoise,reducibleengineeringcostandshortconstructionperiod.Butitsstructural

integrityneedstobeimproved.Therefore,compositeslabswhichcombinetheadvantagesofcast-in-placeslabsandprecastslabsbecomepopular.Itsbottompanelismanufacturedinfactoryandassembledonthespot.Thentheconcreteispouredinplacetoformthecompositeslab.Thisslabisprovidedwithadvantagesofgoodstructuralintegrity,lessscaffoldingandtemplates,shortconstructionperiod,goodeconomicefficiency,soithaspromisingdevelopmentprospects.组合楼板结合了现浇板和预制板优点dominantposition主导地位；category类别；on-siteconcretepouringprocedure现场混凝土浇筑；scaffolding脚手架；template模板；structuralintegrity结构完整性；bottompanel底板；spot现场5.2.1IntroductionThecompositeslabwithpre-stressedbottompanelisthemostwidelyusedcompositeslab.InChina,thepre-stressedthinslabwasproducedupto1957.In1970s,thepre-stressedcompositebeamandslabwasproducedwithcold-drawnlow-carbonsteelwires.In1980s,thestandarddrawingofpre-stressedcompositeslabswascompiled.Nowadays,thecompositeslabhasbeenwidelyusedinthehousingconstruction.Integratedprefabricatedhyperstaticstructureswithcompositecomponents,formedbypre-stressedcompositeslabsandpre-stressedhollowcompositebeams,havebeenappliedintallbuildings.组合板的发展cold-drawnlow-carbonsteelwires冷拔低碳钢丝；standarddrawing标准图册；compile编制；integratedprefabricatedhyperstaticstructures整体预制的超静定结构；pre-stressedhollowcompositebeams预应力空心组合梁5.2.2OverviewofPre-stressedConcreteCompositePlateThebottompanelofcompositeslabsmostlyemploysthefirst-tensionedpre-stressedpanel.Thebottompanelcanalsobeusedaspermanentformworks.Accordingtowhetherornotthebracesaresetunderbottompanels,thecompositeslabcanbesortedintoone-stageloadingcompositeslabandtwo-stageloadingcompositeslab.组合板分类first-tensionedpre-stressedpanel先张拉预应力板；permanentformworks永久性模板；one-stageloadingcompositeslab一阶段加载组合板；two-stageloadingcompositeslab两阶段加载组合板5.2.2OverviewofPre-stressedConcreteCompositePlateTheone-stageloadingcompositeslabhasslenderbottompanel,soitshouldbesupportedbytemporarybracesbeforethebottompanelsareassembled.Thepost-pouredconcretelayerandbottompanelbegintoworktogetherafterpost-pouredconcreteishardened.Theone-stageloadingcompositeslabissimilarwiththecast-in-placeslabinmechanicalbehavior.一阶段加载组合板的做法及特点temporarybraces临时支撑；bottompanels底板5.2.2OverviewofPre-stressedConcreteCompositePlateThebottompaneloftwo-stagecompositeslabhasenoughbendingstiffnessandneedsnotemporarybracesduringconstruction.Soconstructiondurationcanbeshortenedandtheprojectcostcanbereduced.Differentfromthecast-in-placeslab,thecross-sectiondimensionsandreinforcementsofthecompositeslabaredecidedbyconstructionstage,notbyservicestage.Beforethepost-pouredconcretelayerishardened,itbearsnoloads.Inthemeanwhile,thebottompanelitselfbearsitsdeadweight,post-pouredconcrete’sdeadweightandconstructionloads.Afterthepost-pouredconcretelayerishardened,itbeginstoworktogetherwithbottompaneltoformcompositeslab,whichbearsthedeadweightofpost-pouredconcretelayer,floorsurfaceandceilingandliveloadduringservicestage.两阶段加载组合板的做法及特点cross-sectiondimensions截面尺寸；reinforcement配筋5.2.2OverviewofPre-stressedConcreteCompositePlateThebottompanelpatterndeterminesthebondingbehaviorofthecompositeslabandtheedgejointdetailsinfluencesitscrackresistance.Theroughnessofbottompanelsurfacecanaffectthebondforceofcompositeslabs.Accordingtoroughness,thebottompanelcanbedividedintonaturalroughbottompanel,artificialroughbottompanelandshear-resistantreinforcedbottompanel.Accordingtocrosssection,thebottompanelcanbeclassifiedintoflatbottompanel,precastribbedbottompanel,hollowbottompanelandsandwichbottompanel.组合板根据底板粗糙程度和截面形状分类bottompanelpattern底板形状；bondingbehavior粘结性能；crackresistance抗裂性能5.2.3TheResearchandApplicationofPre-stressedCompositeSlabsCompositeslabwithflatbottompanel.Thebottompanelofthecompositeslabwithflatbottompanelispretensionedprestressedsolidslab,whichistheearliesttypeofcompositeslab.平底板混凝土组合板pretensionedprestressedsolidslab先张法预应力实心板5.2.3TheResearchandApplicationofPre-stressedCompositeSlabsThecompositeslabwithflatbottompanelhasinadequatestructuralintegrity.Itsbondperformanceandcrackresistanceofedgejointdetailsneedtobeimproved;thecompositeslabwithbartrussreinforcedprecastconcretebottompanelhasenoughbondforce,butitsstorageandtransportationareinconvenient;theconcretecompositeslabwithprecastribbedpanelhasgoodstructuralintegrityandconvenientconstructionprocedure;thecompositeslabwithhollowbottompanelandthecompositeslabwithsandwichbottompanelhavethefunctionofsoundinsulationandthermalpreservation,howevertheyareinadequatetoresistbendingmomentandhavecomplexconstructionprocedure.Itisconsideredinthispaperthatamongcompositeslabsmentionedabove,theconcretecompositeslabwithprecastribbedpanelhasmoreadvantagesforimprovement.各种形式的组合板的优缺点总结inadequate不足的；bartrussreinforced桁架钢筋；precastribbedpanel预制肋形板；sandwichbottompanel夹心底板；soundinsulationandthermalpreservation隔声保温5.2.4ConclusionUnit6IntroductiontoFoundationAnalysisandDesignEnglishforCivilEngineering——Unit6

IntroductiontoFoundationAnalysisandDesign

6.1Foundations-definitionandPurpose(基础的定义和用途）6.2FoundationClassifications（基础的分类）6.3FoundationSiteandSystemEconomics(基础选址和系统经济）6.4GeneralRequirementsofFoundations（基础的一般要求）6.5FoundationSelection（基础的选择）6.6SIandFPSUnits（SI和FPS单位）

6.7ComputationalAccuracyVersusDesignPrecision（计算精度与设计精度）Allstructuresdesignedtobesupportedbytheearth,includingbuildings,bridges,earthfills,andconcretedams,consistoftwoparts.Thesearethesuperstructure,orupperpart,andthesubstructureelementwhichinterfacesthesuperstructureandsupportingground.Inthecaseofearthfillsanddams,thereisoftennotaclearlineofdemarcationbetweenthesuperstructureandsubstructure.Thefoundationcanbedefinedasthesubstructureandthatadjacentzoneofsoiland/orrockwhichwillbeaffectedbyboththesubstructureelementanditsloads.基础的定义fills

填土；dams

大坝；substructure

下部结构；interfaces

相互作用；demarcation

界限；adjacent

相邻的

6.1Foundations-definitionandPurpose

Thefoundationengineeristhatpersonwhobyreasonofexperienceandtrainingcanproducesolutionsfordesignproblemsinvolvingthispartoftheengineeredsystem.Inthiscontext,foundationengineeringcanbedefinedasthescienceandartofapplyingtheprinciplesofsoilandstructuralmechanicstogetherwithengineeringjudgment(the“art”)tosolvetheinterfacingproblem.Thefoundationengineerisconcerneddirectlywiththestructuralmemberswhichaffectthetransferofloadfromthesuperstructuretothesoilsuchthattheresultingsoilstabilityandestimateddeformationsaretolerable.Sincethedesigngeometryandlocationofthesubstructureelementoftenhaveaneffectonhowthesoilresponds,thefoundationengineermustbereasonablyversedinstructuraldesign.基础工程师的定义mechanics

力学；stability

稳定性；estimated

估计；tolerable

可容忍的；6.1Foundations-definitionandPurpose

6.1Foundations-definitionandPurpose

Itisnowrecognizedthatbothsoilstabilityanddeformationaredependentonthestresshistoryofthemass.Ithasbeencommonuntilrecentlytoassociatefoundationengineeringsolelywithsoilmechanicsconcerns,leavingtheinterfacingelementstothestructural(orother)designer.Currenttrendsaretorecognizethatfoundationengineeringisasystemsproblemandcannotbenicelycompartmentalizedassomepersonswouldprefer.Readersmaydeterminethevalidityofthisstatementastheyprogressthroughthetext.基础是整体结构的一部分solely

单独的；

trends

趋势；

compartmentalized

区别；validity

正确性；6.1Foundations-definitionandPurpose

Thescienceofsoilmechanicsanditsrelationshiptogeologicalprocesseshasprogressedconsiderablyoverthepastfiftyyears.However,becauseofthenaturalvariabilityofsoilandtheresultingproblemsassociatedwithtesting,thedesignofafoundationstilldependstoalargedegreeupon“art”,ortheapplicationofengineeringjudgment.

Asubsetofthisapplicationistheassessmentofthetolerableriskassociatedwiththefoundation.基础设计有不确定性geological

地质学；progressed

发展；variability

变化性；

assessment

估计；6.1Foundations-definitionandPurpose

Theprimaryfocusofthistextwillbeonanalysisanddesignoftheinterfacingelementsforbuildingsandretainingstructuresandthosesoilmechanicsprinciplesparticularlyapplicabletotheseelements.Theseinterfacingelementsincludebothnearsurfacememberssuchasfootingsandmatsanddeepelementssuchaspilesandcaissons.Retainingstructuresofconcrete(commonlytermedretainingwalls)andmetal(assheetpiling)areconsideredinlaterchapters.Soilmechanicsprinciplesincludebothstability,includingsoilwatereffects,anddeformationanalyses.Soilstabilitycanoftenbeenhancedbyvariousimprovementtechniques,themostcommonbeingcompaction.本文关注重点retainingwalls

挡土墙；metal

金属；enhanced

加强；compaction

压实；6.2FoundationClassifications

Foundationsforstructuressuchasbuildings,fromthesmallestresidentialtothetallesthigh—rise,andbridgesareforthepurposeoftransmittingthesuperstructureloads.Theseloadscomefromcolumn—typememberswithstressintensitiesrangingfromperhaps140MPaforsteelto10MPaforconcretetothesupportingcapacityofthesoil,whichisseldomover500kPabutmoreoftenontheorderof200to250kPa.Thereadercanreadilynotethatthisinterfaceconnectsmaterialswhosedifferencesinusefulengineeringstrengthcanvarybyafactorofseveralhundred.交界面材料强度的差距residential

住宅楼；transmitting

传递；intensities

强度；readily

容易的；6.2FoundationClassifications

Typicalfoundationtypesare:Foundationsforbuildings(eithershallowordeep)Foundationsforsmokestacks,radioandtelevisiontowers,bridgepiers,industrialequipment,etc.(eithershallowordeep)Foundationsforportormarinestructures(maybeshallowordeepandwithretainingstructuresextensivelyused)Foundationsforrotating,reciprocating,andimpactmachinery,andforturbines,generators,etc.(eithershallowordeepandmayrequirevibrationcontrol)典型基础的种类smokestacks

烟囱；reciprocating

往复的；turbines

涡轮机；generators

发电机；Abuildingfoundationmustbeadequateifthestructureistoperformsatisfactorilyandbesafeforoccupancy.Otherfoundationsmustbeadequatetoperformtheirintendedfunctionsinasatisfactoryandsafemanner;however,buildingsusuallyhavemorestringentcriteriaforsafetyandperformancethanotherstructures—notableexceptionsbeingnuclear—plantfacilities,turbinesforpowergeneration,andcertaintypesofradio—antennaequipment.Foundationsfornuclearplantsrequireextremelyrigiddesign/performancecriteriaforsafetyreasons.Theotherfoundationssupportextremelyexpensivemachinerywhichisoftenverysensitivetosmallsoildeformations.不同结构基础设计要求不同satisfactorily

令人满意的；occupancy

居住；stringent

严格的；notable

值得注意的；6.3FoundationSiteandSystemEconomics

6.3FoundationSiteandSystemEconomics

Morerecently,andafterlossoflifefromseveralavoidablefailures,damdesignswheresoilistheprincipalconstructionmaterialarebeingmorecarefullymade.Onemightnotethatmoreprinciplesofsoilmechanicsandgeologyapplytoearthdamsthantothemajorityoffoundationengineeringproblems.Inadditiontothestringentcriteriaofthesuperstructure,instabilityandwaterflowthroughthebasesoilareseriousconsiderations.Afurtherareaofconcernistheinevitabledeformationofthebasesoilandsubsidenceinthesuperstructure(damfillmaterial).大坝的设计受到重视avoidable

可避免的；inevitable

不可避免的；subsidence

下沉；6.3FoundationSiteandSystemEconomics

Almostanyreasonablestructurecanbebuiltandsafelysupportedifthereisunlimitedfinancing.Unfortunately,intherealsituationthisisseldom,ifever,thecase,andthefoundationengineerhasthedilemmaofmakingadecisionundermuchlessthantheidealcondition.Also,eventhoughthemistakemaybeburied,theresultsfromtheerrorarenotandcanshowuprelativelysoon—andprobablybeforeanystatuteoflimitationsexpires.Therearereportedcaseswherethefoundationdefects(suchascrackedwallsorbrokenmechanicalfixtures)haveshownupyearslater—alsocaseswherethedefectshaveshownupeitherduringconstructionofthesuperstructureorimmediatelythereafter.工程造价限制带来的问题dilemma

困境；statute

条例；expires

期满；defects瑕疵；thereafter

从那以后6.3FoundationSiteandSystemEconomics

Sincethesubstructureisburied,orisbeneaththesuperstructure,insuchaconfigurationthataccesswillbedifficultshouldfoundationinadequaciesdevelopafterthesuperstructureisinplace,itiscommonpracticetobeconservative.Aoneortwopercentoverdesignintheseareasproducesalargerpotentialinvestmentreturnthaninthesuperstructure.

基础的保险设计beneath

在…下方；configuration

配置；conservative

保守的；overdesign

保险设计；investment

投入6.3FoundationSiteandSystemEconomics

Thedesignerisalwaysfacedwiththequestionofwhatconstitutesasafe,economicaldesignwhilesimultaneouslycontendingwiththeinevitablenaturalsoilheterogeneityatasite.Nowadaysthatproblemmaybecompoundedbylandscarcityrequiringreclamationofareaswhichhavebeenusedassanitarylandfills,garbagedumps,orevenhazardouswastedisposalareas.

基础选址存在的问题constitutes

在…下方；simultaneously

配置；heterogeneity

不均匀性；compounded

组成；reclamation

回收；hazardous危险的6.3FoundationSiteandSystemEconomics

Thefoundationengineermustlookattheentiresystem:thebuildingpurpose,probableservice—lifeloading,typeofframing,soilprofile,constructionmethods,andconstructioncoststoarriveatadesignthatisconsistentwiththeclient/owner’sneedsanddosenotexcessivelydegradetheenvironment.Thismustbedonewithasafetyfactorwhichproducesatolerableriskleveltoboththepublicandtheowner.基础设计考虑整个系统的建设profile

剖面；consistent

一致；client

客户；degrade

降级6.3FoundationSiteandSystemEconomics

Consideringtheseseveralareasofuncertainly,itfollowsthatriskandliabilityinsuranceforpersonsengagedinfoundationengineeringisverycostly.Inattemptstoreducethesecostsaswellasproduceadesignwhichcouldbeobtainedfromseveralengineeringfirms(i.e.a“consensus”design)thereisactivediscussion(andthepracticehasalreadybeenundertakeninseveralareas)ofhavingthefoundationengineersubmittheproposeddesigntoaboardofqualifiedengineersfora“peerreview.”

风险和责任保险liability

责任；undertaken

一致；submit

提交；peer

同行Afoundationmustbecapableofsatisfyingseveralstabilityanddeformationrequirementssuchas:Depthmustbeadequatetoavoidlateralexpulsionofmaterialfrombeneaththefoundation—particularlyforfootingsandmats.Depthmustbebelowthezoneofseasonalvolumechangescausedbyfreezing,thawing,andplantgrowth.Systemmustbesafeagainstoverturning,rotation,sliding,orsoilrupture(shear—strengthfailure).基础的要求expulsion

排挤；seasonal

季节的；thawing

融化；sliding

滑动；rupture破裂6.4GeneralRequirementsofFoundations

6.4GeneralRequirementsofFoundations

Systemmustbesafeagainstcorrosionordeteriorationduetoharmfulmaterialspresentinthesoil.Thisisaparticularconcerninreclaimingsanitarylandfillsandsometimesformarinefoundations.Systemshouldbeadequatetosustainsomechangesinlatersiteorconstructiongeometry,andbeeasilymodifiedshouldlaterchangesbemajorinscope.Thefoundationshouldbeeconomicalintermsofthemethodofinstallation.Totalearthmovements(generallysettlements)anddifferentialmovementsshouldbetolerableforboththefoundationandsuperstructureelements.Thefoundation,anditsconstruction,mustmeetenvironmentalprotectionstandards.基础的要求sustain

排挤；modified

修改；installation

安装；movements

运动；settlements沉降6.5Foundationsselection

基础种类和适用土壤条件Spreadfooting

扩展基础；

stratum

层；

differential不均匀；

consolidation

固结；FoundationtypeUseApplicablesoilconditionsSpreadfooting,wallfootingsIndividualcolumns,walls,bridgepiersAnyconditionswherebearingcapacityisadequateforappliedload.Mayuseonsinglestratum:firmlayeroversoftlayerorsoftlayeroverfirmlayer.Checkimmediate,differential,andconsolidationsettlements.FoundationtypeUseApplicablesoilconditionsSpreadfooting,wallfootingsIndividualcolumns,walls,bridgepiersAnyconditionswherebearingcapacityisadequateforappliedload.Mayuseonsinglestratum:firmlayeroversoftlayerorsoftlayeroverfirmlayer.Checkimmediate,differential,andconsolidationsettlements.

基础类型用途适用的土壤条件

扩展基础，墙基础独立柱，墙壁，桥墩

承载力足以满足所施加载荷的任何情况。可以在单一土层上使用：硬层上覆软层或软层上覆硬层。需验算短期，局部以及总沉降。6.5Foundationsselection

6.5Foundationsselection

基础种类和适用土壤条件Spreadfooting

阀板基础；

basement地下室；

Corrosive

腐蚀性的；MatfoundationSameasspreadandwallfootings.Veryheavycolumnloads.UsuallyreducesdifferentialsettlementsandtotalsettlementsGenerally,soilbearingvalueislessthanforspreadfootingsoverone-halfareaofbuildingcoveredbyindividualfootings.Checksettlements.PilefoundationsFloatingIngroups(atleast2)tocarryheavycolumn,wallloads;requirespilecapPoorsurfaceandnearsurfacesoils.Soilsofhighbearingcapacity20-50mbelowbasementorgroundsurface,butbydisturbingloadalongpileshaftsoilstrengthisadequate.Corrosivesoilsmayrequireuseoftimberorconcretepilematerial.

MatfoundationSameasspreadandwallfootings.Veryheavycolumnloads.UsuallyreducesdifferentialsettlementsandtotalsettlementsGenerally,soilbearingvalueislessthanforspreadfootingsoverone-halfareaofbuildingcoveredbyindividualfootings.Checksettlements.PilefoundationsFloatingIngroups(atleast2)tocarryheavycolumn,wallloads;requires