ACI 336.2R-88 Suggested Analysis and Design Proced

ACI336.2R-88(Reapproved2002)SuggestedAnalysisandDesignProceduresforCombinedFootingsandMatsReportedbyACICommittee336EdwardJ.UlrichShyamN.ShuklaChairmanSecretaryClydeN.Baker,Jr.StevenC.BallJosephE.BowlesJosephP.ColacoXI.T.DavissonJohnA.Focht,Jr.M.GaynorJohnP.GnaedingerFritzKramrischHughS.Lacy.JimLewisJamesS.NotchIngvarSchousboeThisreportdealswiththedesignoffoundationscarryingmorethanasinglecolumnofwallload.Thesefoundationsarecalledcombinedfootingsandmats.Althoughitisprimarilyconcernedwiththestruc-turalaspectsofthedesign,considerationsofsoilmechanicscannotbeeliminatedandthedesignershouldfocusontheimportantinter-relationofthetwofieldsinconnectionwiththedesignofsuchstruc-turalelements.Thisreportislimitedtoverticaleffectsofallloadingconditions.Thereportexcludesslabsongrade.Chapter4-Combinedfootings,p.336.2R-74.l-Rectangular-shapedfootings4.2-Trapezoidalorirregularlyshapedfootings4.3-OverturningcalculationsKeywords:concretes;earthpressure:footings:foundations;loads(forces);matfoundations:reinforcedconcrete;soilmechanics;stresses;structuralanalysis;structuraldesign.Chapter5-Gridfoundationsandstripfootingssupportingmorethantwocolumns,p.336.2R-85.l-General5.2-Footingssupportingrigidstructures5.3-ColumnspacingCONTENTSChapter1-General,p.336.2R-25.4-Designprocedureforflexiblefootings5.5-Simplifiedprocedureforflexiblefootings1.1-Notation1.2-Scope1.3-Definitionsandloadings1.4-Loadingcombinations1.5-Allowablepressure1.6-Time-dependentconsiderations1.7-DesignoverviewChapter6-Matfoundations,p.336.2R-9Chapter2-Soilstructureinteraction,p.336.2R-42.1-General2.2-Factorstobeconsidered2.3-InvestigationrequiredtoevaluatevariablefactorsChapter3-Distributionofsoilreactions,p.336.2R-63.1-General6.1-General6.2-Finitedifferencemethod6.3-Finitegridmethod6.4-Finiteelementmethod6.5-Columnloads6.6-Symmetry6.7-Nodecouplingofsoileffects6.8-Consolidationsettlement6.9-Edgespringsformats6.10-Computeroutput6.11-Two-dimensionalorthree-dimensionalanalysis6.12--Matthickness6.13-Parametricstudies6.4-Matfoundationdetailing/construction3.2-Straight-linedistribution3.3-DistributionofsoilpressuregovernedbymodulusofsubgradereactionChapter7-Summary,p.336.2R-20ACICommitteeReports,Guides,StandardPractices,andCommentariesareintendedfor.guidanceindesigning,plan-ning,executing,orinspectingconstructionandinpreparingspecifications.ReferencetothesedocumentsshallnotbemadeintheProjectDocuments.IfitemsfoundinthesedocumentsaredesiredtobepartoftheProjectDocumentstheyshouldbephrasedinmandatorylanguageandincorporatedintotheProjectDocuments.ThisreportsupercedesACI336.2R-66(Reapproved1980).Copyright02002,AmericanConcreteInstitute.Allrightsreservedincludingrightsofreproductionanduseinanyformorbyanymeans,includingthemakingofcopiesbyanyphotoprocess,orbyanyelectronicormechanicaldevice,printed,written,ororal,orrecordingforsoundorvisualreproductionorforuseinanyknowledgeorretrievalsystemorde-vice,unlesspermissioninwritingisobtainedfromthecopyrightproprietors.JohnF.SeidenstickerBruceA.SuprenantJagdishS.SyalJohnJ.Zils336.2R-1336.2R-2MANUALOFCONCRETEPRACTICEChapter8-References,p.336.2R-218.1-Specifiedand/orrecommendedreferences8.2-CitedreferencesCHAPTER1-GENERAL1.1-NotationThefollowingdimensioningnotationisused:F=force;e=length;Q=dimensionless.A=b=B=Bm=Bp=c=D=Do=Df=baseareaoffooting,e2widthofpressededge,lDst=e=ei=E=Ec=E’=Es=Fvh=G=hw=H=Hci=AH=I=IB=IF=Iw=i=J=kp=ksi=k'si=ks=foundationwidth,orwidthofbeamcolumnelement,4matwidth,Pplatewidth,!distancefromresultantofverticalforcestooverturningedgeofthebase,!deadloadorrelatedinternalmomentsandforces,Fdeadloadforoverturningcalculations,FthedepthDfshouldbethedepthofsoilmeasuredadjacenttothepressededgeofthecombinedfootingormatatthetimetheloadsbeingconsideredareappliedstagedeadloadconsistingoftheunfactoreddeadloadofthestructureandfoundationataparticulartimeorstageofconstruction,Feccentricityofresultantofallverticalforces,Peccentricityofresultantofallverticalforceswithrespecttothex-andy-axes(exandey,respectively),!verticaleffectsofearthquakesimulatingforcesorrelatedin-ternalmomentorforce,Fmodulusofelasticityofconcrete,F/e2modulusofelasticityofthematerialsusedinthesuperstruc-ture,F/l?’soilmodulusofelasticity,F/e2verticaleffectsoflateralloadssuchasearthpressure,waterpressure,fillpressure,surchargepressure,orsimilarlateralloads,Fshearmodulusofconcrete,F/e’heightofanyshearwallsinstructure,esettlementoffoundationorpoint,!consolidation(orrecompression)settlementofpointi,lmagnitudeofcomputedfoundationsettlement,t’planmomentofinertiaoffooting(ormat)aboutanyaxisx(Ix)ory(Iy),f”momentofinertiaofoneunitwidthofthesuperstructure,t”momentofinertiaperoneunitwidthofthefoundation,t”baseshapefactordependingonfoundationshapeandflexi-bility,e4verticaldisplacementofanode,t!torsionconstantforfinitegridelements,e4coefficientofsubgradereactionfromaplateloadtest,F/l3coefficientofsubgradereactioncontributiontonodei,F/E’revisedcoefficientofsubgradereactioncontributiontonodei,F/4”,seeSection6.8q/6=coefficient(ormodulus)ofverticalsubgradereac-tion;generictermdependentondimens