PEB and IS-800-2007

30/04/2015 www.sefindia.org::ViewtopicPreEngineeredBuildingsandIS8002007

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Pre Engineered Buildings and IS 8002007Gotopage1,2Next

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shenoyBronzeSponsor

Joined:13Nov2008Posts:33Location:Bangalore,Mangalore,Kochi

Posted:MonFeb09,200912:57amPostsubject:PreEngineeredBuildingsandIS8002007

IwouldliketoreopenanissuerelatedtoPreEngineeredBuildings,withtheavailabilityofLatestIS8002007.

WhiletheAnalysisofanyStructurewouldbeuniversal,designsneedtobedoneasperthelocal/regionalcodes.OtherwisewhydifferentcountrieshavedifferentcodesofPractice?Forexample,IfaPEBisbuiltinIndia,TheloadcalculationsneedtobeasperthelatestIS875,thedesignsneedtobeasperIS800formainframemembers,asperIS801forthinrolledsecondarymembers(ZandCpurlinsandGirts).Ifacountrydoesnothaveacode,thebuildingmayfollowtheUBC,orthecodeofacountrynearbyIFsuitable.Tomakethesuperstructuremosteconomicalandverycompetitive,mostofthePEBvendorsselectthecodesasperTHEIRrequirement.Forexample,forastructurebuiltinIndia,theymightcalculatetheloadsasperIS875,butdothedesignasperAISCorAISI,MBMAanduseweldsasperAWS.IftheyfeelthattheSteelSectionislighterasperonecode,theywilladoptTHATclauseofthecodeandselectanotherclauseofanothercodeofanothercountryforthedesignofsomeotherpartofthesamebuilding.SomePEBvendorsselectsomeclausesofPreviousversionsoftheCodeandotherclausesoftheLatestVersions!Thisstyleisnotthesameeverytime.PEBDesignteamsareonconstantresearchintheSelectionofCodalprovisionsofVariouscountriesandareontrialswithdifferentclauses.Thiswayofvarieddesignisnotlegallyvalid.IftheloadsandCodesarenotspecifiedbythebuyer,ItisbindingonthePEBsuppliertousetheLocal/RegionalCodesofpractice.TheevolutionofaCodeofPracticeisbasedontheWeather&otherclimaticconditions,Material,LocalPractices,Skilllevelsatmanufacturing,Transporting,Assembling,erecting,finishingandmaintaining.HenceitisridiculoustouseIndianSteelplateofanyyieldstress,CutandmanufacturedinIndia,Loaded&transportedinIndianStyle,UnloadedandstackedinIndianStyle,Assembled&erectedbyIndian(skilled)Labour,FinishedbyIndianPaintersusingIndianpaints,MaintainedbyIndianClientinanIndianTownorvillageBUTDESIGNEDUSINGAMERICANCODE!Mostoftheclients,ArchitectsandEngineersinIndiafeelthatAmericanCodesareBetterthanIndian!Clients,ArchitectsandEngineersinIndia,Beware!ThePreEngineeredBuildingsarenotaNewConcept.ButtheJumpingCodePracticeistheNEWConceptandSTYLE.IfyouarenotSureoftheCodes,DONOTSIGNaPurchaseorderjustcopyingtheSpecificationsgivenbythePEBVendor.JustmentionsomewherethattheLatestRevisionsofIndianStandardCodesshouldbefollowed.Luckily,IndiahasallthecodesavailableforthedesignofallthePartsofaPEBstructure.IwishtogetCommentsfromyouall.

PremanandShenoy.M.Tech,MIE,FIAStructEStructuralConsultantandManagingPartnerRoy&Shenoy,India.

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abhayguptaSEFIRegulars

Joined:29Nov2008Posts:21

Posted:MonFeb09,20092:16amPostsubject:

IfullyagreewiththeviewsexpressedbyMr.ShenoyandIhaveexpressedsimilarattherecentlyconcludedTwodayworkshoponSteelStructuresfocussingonPEBs,atDelhiorganisedbyIAStructE.

ThoughIamHeadEngineeringforoneofthePEBmanufacturingcompanybutIalsosupportthatBuildingsinIndiashouldbeDesignedandManufacturedasperIndianCodes,asfarastheprovisionsareavailableinIScodes.OthercountrycodesmaybeusedforthiseitemswhicharenotproperlydefinedinIScodes.However,onlyforimprovedpracticesandbetterperformanceothercodesandliteraturemaybereferredbutnotforeconmisation.Aholisticapproachisbetterthanahybridoneaimedforeconomyonly.Evenwhentheclientspecifiesforothercountrycode,weshouldexplainthemthatwhyIScodesarerelevantinIndiaanduseIScodes.

IhaveproposedthatadiscussionplatformbetweenPEBdesignersandConsultantsshouldbeorganisedbySEFIorIAStructEtostreamlinethepractice.WeareatthethresholdofanerafromwherewearereadytoembarktowardstheEteelintensiveconstructioninIndiaandthisistheappropriatetimeforcorrectingthepractice.

Plcomeforward.

Regards,AbhayGupta

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padamkr1SEFIMember

Joined:26Jan2003Posts:18

Posted:MonFeb09,20097:47amPostsubject:PreEngineeredBuildingsandIS8002007

MRABHAYGUPTA,

COULDYOUPLZ.UPLOADURPRESENTATIONONSEFI,GIVENATSEMINARONSTEELSTRUCTURESASPROMISEDBYYOURSELF

padamkumar

OnMon,9/2/09,abhayguptawrote:Quote:

From:abhayguptaSubject:[SEFI]Re:PreEngineeredBuildingsandIS8002007To:[email protected]:Monday,9February,2009,7:46AM


ThoughIamHeadEngineeringforoneofthePEBmanufacturingcompanybutIalsosupportthatBuildingsinIndiashouldbeDesignedandManufacturedasperIndianCodes,asfarastheprovisionsareavailableinIScodes.OthercountrycodesmaybeusedforthiseitemswhicharenotproperlydefinedinIScodes.However,onlyforimprovedpracticesandbetterperformanceothercodesandliteraturemaybereferredbutnotforeconmisation.Aholisticapproachisbetterthanahybridoneaimedforeconomyonly.


Plcomeforward.

Regards,AbhayGupta

Cricketonyourmind?Visittheultimatecricketwebsite.Enternow!

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Dr.N.SubramanianGeneralSponsor

Posted:TueFeb10,20093:46pmPostsubject:PreEngineeredBuildingsandIS8002007

Hiall,



Joined:21Feb2008Posts:4876Location:Gaithersburg,MD,U.S.A.

IalsofullyagreewiththestatementsmadebyMr.Shenoy.Itwillbedangeroustodesignastructurebytakingdifferentclausesfromdifferentcodes,justbecauseyoulikethemortheyareconvenienttoyou!

WehavedesignedafewPEBbuildings.OneofthebuildingsisinTICyclesfactory,Chennai.ItwasdesignedlongagoandIhopeitmaybeoneoftheearliestbuildingsinIndiabuiltusingPEBconcept.ThecoldformedsectionsandsheetingsweresuppliedbyTIMetalsections(India).WeusedIS801fordesigningit.UnfortunatelyTIMetalsectionswentoutofbusiness,duetoseveralreasonsandthecompanywasboughtbyTigerSteels.(WeevendesignedtheChassisofacarusingcoldformedsections,withhelpfromProf.ARSanthakumarofAnnaUniv.NowheisinIITM.WealsodesignedAirporttrolliesforaSaudicompany,withhelpfrommyfriendDr.G.MuthuveerappanofIITMMech.Engg.dept)

IS800:2007doesnotcontainprovisionsforthedesignofcoldformedsections.ThereisnoharminusingIS801fordesigningcoldformedsections.OnlythingisthatitusesAllowablestressmethodandusestheeffectivewidthconcept,proposedbyProf.Winterin1950s(TheapplicabilityoftheeffectivewidthconcepttounstiffenedelementsunderuniformcompressionwasstudiedindetailbyProf.Kalyanaramanetal.(1977),whotestedalargenumberofbeamsandshortcolumnsthatcontainedwebelementsthatwerefullyeffective.TestsofasimilarnaturepreviouslyreportedbyWinter(1947,1970)andtheexperimentalandanalyticalresearchbyKalyanaramanetal.(1977),ledtotheadoptionoftheeffectivewidthapproachforuniformlycompressedunstiffenedelementsinthe1986editionoftheAISISpecificationandsubsequentlyinIS801.

TheAustralian,BritishandEuropeancodesallowaccuratecalculationoftheelasticbucklingcoefficient,howeverthesameeffectivewidthequationforcompressedelementsisusedforelementswithstressgradients.Inallcases,thedesignprovisionsproducebendingcapacitiesupto50%conservativeforsectionscontainingunstiffenedelementsunderstressgradients).Recently,BambachandRasmussen(2002),havedevelopedageneraldesignprocedureforsectionsthatcontainunstiffenedelementsunderstressgradients,beyondthepointofinitiationofyieldinginthesection,usingtheplasticeffectivewidth.ThecurrentAISIspecificationsarebasedontheDirectDesignmethoddevelopedbyProf.Dr.Schafer.Hiswebsitecontainsanumberoflinkspertainingtodesignofcoldformedsectionswww.ce.jhu.edu/bschafer

IS801isunderrevision.Maybetherevisededitionofthecode,inlimitsstatesdesignformat,willbereleasedbyBISin2014!

Ref:1.Kalyanaraman,V.,Pekoz,T.andWinter,G.(1977)."UnstiffenedCompressionElements."JournaloftheStructuralDivision,ASCE,103(ST9),183318482.Bambach,M.R.andRasmussen,K.J.R.(2002a)."DesignmodelsforThinWalledSectionsinBendingcontainingUnstiffenedElements."ResearchReport,R820,DepartmentofCivilEngineering,UniversityofSydney,Sydney.

Dr.N.Subramanian,

OnMon,2/9/09,abhayguptawrote:Quote:

From:abhayguptaSubject:[SEFI]Re:PreEngineeredBuildingsandIS8002007To:[email protected]:Monday,February9,2009,7:46AM


ThoughIamHeadEngineeringforoneofthePEBmanufacturingcompanybutIalsosupportthatBuildingsinIndiashouldbeDesignedandManufacturedasperIndianCodes,asfarastheprovisionsareavailableinIScodes.OthercountrycodesmaybeusedforthiseitemswhicharenotproperlydefinedinIScodes.However,onlyforimprovedpracticesandbetterperformanceothercodesandliteraturemaybereferredbutnotforeconmisation.Aholisticapproachisbetterthanahybridoneaimedforeconomyonly.




Plcomeforward.

Regards,AbhayGupta

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shenoyBronzeSponsor


Posted:WedFeb11,20094:51amPostsubject:PreEngineeredBuildingsandIndianCodes

IthankDr.AbhayGupta&Dr.NSubramanianfortheircomments.

IamhappythatProfessionalStructuralEngineersarebreakingtheirshelltotelltheirfeelings.

PEBisnotacommoditywhichcanbesoldlikeapenorblanket,wherethesalestakeplacemainlyuponthecapabilityofthesalesman.

ManyofthebuyersarehappytogetthesuperstructureofthewholebuildingsuppliedtotheminalesstimeforaLumpsumamount,allinclusive.IwastoldbyoneofthePEBsuppliersthatthesectionsalsodependonthefinancialnegotiations!

LetustaketheadvantagesofOptimumcostoftheentirebuilding(NotonlythePEBsuperstructure),QualityManufacture,inlessamountoftime,erectedbyqualified&trainedskilledworkers,maintainedbytheclientattheminimumcost.

AllthePEBsuppliersneedtoquotefortheentirebuilding,notonlythesuperstructure.

AsDr.AbhayGuptasuggesteditistimethatwehadacommonforumtodiscusstheseissues.

PremanandShenoy.

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amarjeetsingh...

Joined:09Nov2008Posts:129Location:newdelhi

Posted:WedFeb11,20097:32amPostsubject:PreEngineeredBuildingsandIS8002007

dearall,

themajorproblembeingfacedisthattheconsultantsarenotabletogetthedrawings/datafromthePEBvendorintime.ThePEBvendorishappytoshareonlytheanalysisinputfileandtheoutputfilesanditisnexttoimpossibletodiscussthedesignoftheweld,weldthickness,connectiondetailssuchasrafterrafter,raftercolumn,baseplatedesign,boltsdesignetc.

TheclientgoesforPEBtosavetimeandthevendortakesadvantageofthesamebyalwaystakingshelterbehindthetimelines.

Theloadcombinationusedinanalysisanddesignalsovaryfromvendortovendor.Itisverydifficult(notimpossible)tochecktheweldthicknessesatsiteandtheywillalwaysasktheconsultanttocheckthesameinfactory.

ThemainconsultantissharingtheresponibilitywiththePEBvendorsanditishightimethattheytheyshouldalsoopenup.

regrds

amarjeetsingh

OnWed,Feb11,2009at10:21AM,shenoywrote:Quote:




ManyofthebuyersarehappytogetthesuperstructureofthewholebuildingsuppliedtotheminalesstimeforaLumpsumamount,allinclusive.IwastoldbyoneofthePEB



suppliersthatthesectionsalsodependonthefinancialnegotiations!




PremanandShenoy.

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sdec.inSilverSponsor

Joined:26Jan2003Posts:473

Posted:WedFeb11,20098:01amPostsubject:PreEngineeredBuildingsandIS8002007

DearMrShenoyIhopeyouareawarethatalmostallthePEBsuppliersinIndia(andevenabroad)areonlyPEBvendorsandnotequippedwithanyRCCorCivilworkstafforequipmentsorexperiencetothateffect.So,muchaswewouldlikethemtoquotefortheotherwork,theyareneitheradequatelyequippedtohandlethatworknorareinterestedintakinguptheadditionalheadacheorburden(anditalsogivesthemascapegoattoblameincaseofdelays!!)Andinmostcases,theyonlyquotepersqmofcoveredarea,withoutgivinganydetailsaboutthedesignsbeingfollowedorwhetherIndian/AmericanCodesarebeingfollowed,unlesscompelledtodothat.OnehastousethePEBproducts,withawordofcaution,andframethecontractprovisionsaccordingly.Wearefairlyclosetoadaywhensteelbuildingsshouldbetherule,ratherthanbeingtheexception,ifweworktogethertogivetheClient,bestvalueforhismoney.RegardsSangeetaWij

Quote:

OriginalMessageFrom:shenoy([email protected])To:[email protected]([email protected])Sent:11February,200910:21AMSubject:[SEFI]Re:PreEngineeredBuildingsandIS8002007




ManyofthebuyersarehappytogetthesuperstructureofthewholebuildingsuppliedtotheminalesstimeforaLumpsumamount,allinclusive.IwastoldbyoneofthePEBsuppliersthatthesectionsalsodependonthefinancialnegotiations!




PremanandShenoy.

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thensenamarmpProgressiveMember

Joined:31Jul2008Posts:46

Posted:WedFeb11,200911:56amPostsubject:

dearall,whatisthemethodologyofanalysis&designingofpebbuilding's.



regardsthensenamarmp

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Dr.N.SubramanianGeneralSponsor

Joined:21Feb2008Posts:4876Location:Gaithersburg,MD,U.S.A.

Posted:WedFeb11,20091:48pmPostsubject:PreEngineeredBuildingsandIS8002007

HiMr.Thensenamar,

Analysisissamelikeanyotherstructure,youhavetoonlychangethepropertiesasperthesectionsused.IfyouareusingColdformedsteelsections,youhavetouseIS801fordesign!

Bestwishes

NS

OnWed,2/11/09,thensenamarmpwrote:Quote:

From:thensenamarmpSubject:[SEFI]Re:PreEngineeredBuildingsandIS8002007To:[email protected]:Wednesday,February11,2009,5:26PM

dearall,whatisthemethodologyofanalysis&designingofpebbuilding's.

regardsthensenamarmp

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shenoyBronzeSponsor


Posted:WedFeb11,20092:11pmPostsubject:DesignofPEBsanOverview

DearThensenamar,

IwouldliketoelaboratetoyouasanextensiontothepostbyDr.Subramanian.

TheLoadcalculationsaredoneasinthecaseofaregularframe.Normally,thecriticalcasegoverningthedesignswouldbeDL+WLconditionsasthePEBslopesareminor(like1in10).

ThesupportconditionsarenormallyHinged,butitissometimesbeneficial,onaselectivebasistouseafixedconditiongivingagussettedbaseplateandAnchorboltcombination.

InHingedbasecondition,thesectionisnormallytapereddownandprovidedwithaBoltedconnectiontothebase.

AlltheotherJointswouldbeNormallydesignedasRigidjointsandsteelconnectionsaremomentconnections,transferringtheaxial,momentandshearvaluesbetweenthesectionsconnected.

IntheWindloadcalculations,theBasicWindspeedaremultipliedbyCoefftslikek1,k2,k3(andnowmoreaspertheDraftcodeofIS875Part3),AlgebraicCombinationsofExternalandInternalPressurecoefficientsCpe&Cpi,forvariouspermeabilityconditionsofwallfacingthewindandthedirectionofwind.

SincetheSectionswouldbetaperedtoeconomisethesteel,ItwouldbedifficulttoanalysetheFramemanually(unlessyoufollowanIterativeanddifficultmMdiagramsandIntergratingthemtoequatethedifflections,thattooforaninclinedmemberlikeRafter).Henceacomputerhelpissought.TherearemanysoftwarepackagesdevelopedinhousebytheVenders.ButIftheyaretobeproducedasAuthentic(?)STAADoranyothersoftwareisused,whichhasthecapabilityofhandlingNonPrismatic



(Tapered)Members.ButOnecanUseanyothersoftwaretoo,bydescretisingtheTaperedmembertoalotofprismaticmembers,toasufficientaccuracyrequired.

GettheBM,SF,AxialForcesfortheentiresectionsoftheFrame.ByPractice,onewillknowthecriticalsections.DesignallthesectionsForalltheindividualandcombinedeffectsofBending,ShearandAxialStressesandcheckthemagainstpermissiblevaluesincaseofWorkingstressmethod.ThemainpointtobenotedhereisthepossibilityoflocalbucklingofindividualplatesofflangesandWeb.(Iflimitstatemethodistobefollowed,FactoriseindividualBM/SF/AxialforcesfortherequiredcombinationsofDL/IL/WLorEL(onlyWLorELisappliedatatime,notBoth)andcheckagainstthelimitingStresses.

IwouldsuggestanexcellentandtheLatestBookbyDr.N.Subramanianhimself,"DesignofSteelStructures",publishedbyOxfordUniversityPress,forallthese.(Iamproudtosaythis,Heisjustshytotellyouthisreference)

Usually,CheckingtheCombinationStressesandcomparingwiththelimitingwalues(inLSDorWSD)isdoneusinganinteractivesoftware,whichcalculatestheExploitationefficiencyofthesection.ieiftheActualStress/permittedstressis0.95,itmeansthatthethesectionisexploitedfor95%ofitsstrength.Forthisthetotalweightoftheframeiscalculated.Ano.oftrailsaredonesuchthatsectionsaredesignedwithVariableslikeFlangethk,Webthk,FlangeWidth,WebDepth,sothattheEntireframebecomestheoreticallysafe,andisofminimumwt!(IndianCodeIS800).RememberthatIfyougoonreducingthethicknessoftheplates,theWidth/thicknessvalueofplateswillgrowandtheentiresectionalareawillnotbeeffective.

Checkingfordefectionsisthenextstep.manytimessectionsneedtoberevisedtoholdthetheoreticalmaximumdeflectionswithinthepermissibleones.(ThedeflectionsaretobecalculatedforActualLoadsonly,NotforFactoredLoads,SinceDeflectionisaserviceLimitstate)

SomeVendorsexploit90%ofthesection,leaving10%forprobablelapsesinmanufacturing,transporting,assembling&erection.Butthecompetitionhasmade(forced)peoplebelievethattherearenolapsesanywhere!

TheNextimportantstepistodesigntheweldsbetweentheflangesandWebs.Heretoo,Efficiencyoftheweldplaysanimportantpart.Hence,PEBpeoplewillavoidanyweldatthesite,becausea4.5mmweldattheshopmaybebetterthan6or8mmweldatthesite.

NextstepistodesigntheFieldjoints(Wherethepartsareassembledatthesite).Theresultantforcesareknownatthejoints,designaboltedconnection,preferablyperpandiculartotheplaneofframe,toexploittensilecapacityofboltsforBMsratherthantheshearcapacities.henceNoofboltsrequiredfortheconnectionwillreduce,probably,willaskforaconnectionplateperpendiculartotheframeplane.ThesejointsarealsoplacedatOptimumlocations!Optimisationeverywhere.

ThesecondarymemberslikePurlinsandGirtsaredesignedaspercodesforthinColdFormedSections,withorwithoutlip.OnecanusemanyspanreducingandLateralsupportingtechniqueslikesagrodsandkneebracings,tierodstoOptimisethesections(IndiancodeIS801).

CompetitionhasleadthethePEBvendorsdoresearchinthewaysofoptimisationtoo.SelectionofCodestoreducetheweight,butsatisfysomecodalprovisionsisoneofthem.HenceyoumightfindaSupplierjumpingfromIScodetoAISCorMBMAguidelineclaimingthat'THATCODEIStheLATEST'.AslongastheintentionistomaketheBestbuildingeverythingshouldbeacceptedgreedily.Butiftheintentionsaretoreducethematerialinputtothebuilding,VendorsbecomeCheapSellerswhoreducethequalityaccordingtotheBargainsonthePrice.

ManyPEBVendorsconfinethemselvesto'SUPPLYTOYOURSITE'only.TheClientneedstofindanagencytoerectthestructure.ButthePEBVendorHELPSyou(atnoextracost)findanapprovedagencytodothesame.YoucanusehiserviceswithnobindingonthePEBVendor.

Nowtoendthispost,LetmequoteSangeethaWij(withherpermission?)

"OnehastousethePEBproducts,withawordofcaution,andframethecontractprovisionsaccordingly.Wearefairlyclosetoadaywhensteelbuildingsshouldbetherule,ratherthanbeingtheexception,ifweworktogethertogivetheClient,bestvalueforhismoney."

Irepeat,thebestvalueforhismoney(includingthestructuralconsultant'sfees).

PremanandShenoy.(Hew!!DidItypethismuch?!!,Thensenamar,Haveyoureaditfully??)



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