土木建筑外文翻譯外文文獻(xiàn)英文文獻(xiàn)消防自動(dòng)噴水滅火系統(tǒng)抗震設(shè)計(jì)

1、TheEvolutionofSeismicDesignofFireSprinklerSystemsRussellP.Fleming,P.E.ExecutiveVicePresidentNationalFireSprinklerAssociationPatterson,NYSpecialfiresprinklersysteminstallationguidanceintendedtoguardagainstdamageduetoearthquakesfirstappearedintheNorthAmericansprinklerinstallationstandardin1947,andwasl

2、argelybasedonexperienceintheLongBeachearthquakeof1930.AtthattimemanybuildingcodesinuseintheUnitedStatesdidnotevenaddressthesubjectofearthquakes.InsurancereportsoftheLongBeachearthquakehadindicated90damagedsprinklersystems.Thefirstguidance,containedonlyintheappendix,calledfor1to2inchesclearancearound

3、pipes,flexiblecouplingsinrisersand"someformoflateralandlongitudinalbracing"forfeedandcrossmains.Inthe1951editionrequirementswereplacedinthebodyofthestandardforplacementoflongitudinalandlateralbraceswithspacingindicatedas"30to40ft",amaximumslendernessratioofbracemembersof200,andfl

4、exiblecouplingsonriserswhereitwasnecessarytoprotectsystemsagainstearthquakes.Thestatedintentwastolaterallybracefor50%ofweightofwater-filledpipingandattachments.InthedecadessincethendeliberateeffortshavebeenmadetoclarifytherulesandimproveprotectionwithinthetextofNFPA13-InstallationofSprinklerSystems,

5、butalwayswiththeintentofaddressing"how"systemsaretobeprotectedagainstearthquakes,not"where"suchpisotecbioiprovided.Itwasrecognizedthatbuildingcodesandotherauthoritiesmadethebasicdecisionswithregardtothelocationofearthquake-proneareas.AlthoughtheearliestguidancecontainedinNFPA13ca

6、mefromtheinsuranceindustryinthewesternstates,theNFPACommitteeonAutomaticSprinklersformedanEarthquakeProtectionSubcommitteein1985.Oneofthegoalsofthissubcommitteewastodevelopameanstoaddressthebracingofsprinklersystemsinthesamemannerthattheapplicationofsystemhydraulicshadbeenaccomplished.Althoughacompl

7、exsubject,itwasbelievedthatmanyofthedesignaspectscouldbepre-engineeredintotablesandthenproperlyappliedbythetechnicianswhonormallylayoutanddetailfiresprinklersystems.The1983standardcontainednoinformationonthesizingorfasteningofbracingrelativetoloads.Amethodwasproposedin1984wherebyzonesofinfluence&quo

8、t;couldbeevaluatedtodeterminetotalloadsforproposedbracelocations.Tableswereproposedfordeterminingmaximumbraceloadsandallowablefastenerloadsbasedonsixdifferentcombinationsofbraceandfastenerorientationandanglefromvertical.Thisconceptandtheaccompanyingtableswereacceptedintotheappendixofthestandardinthe

9、1987edition,andinthe1989editionthetableswereexpandedtoninecombinationsoforientationandangleandmovedintothebodyofthestandard.2007StructuresCongress:NewHorizonsandBetterPractices?2007ASCECopyrightASCE2007StructuresCongress2007Downloaded06Mar2009toRedistributionsubjecttoASCElicenseorcopyright;seeNFPA13

10、EarthquakeProtectionSubcommitteewasinplaceatthetimeoftheLomaPrietaandNorthridgeearthquakesin1989and1994,andheldpublichearingsincooperationwiththeNationalFireSprinklerAssociationandtheSocietyofFireProtectionEngineersfollowingthoseeventsinordertoevaluatehowfiresprinklersystemsperformedduringtheearthqu

11、akesandstodevelopsuggestionsforimprovementstotheprotectioncriteriawithinthestandard.Ingeneral,theperformanceoffiresprinklersystemsinthoseearthquakeswasjudgedtobegood,withastrongcorrelationbetweenobservedfailuresanddeparturesfromtherulesofNFPA13.Oneareaacknowledgedtobeinneedofimprovementwastheinterac

12、tionofsprinklersandceilings;impactofsprinklersagainstrigidceilingsresultedinaseveralhigh-profileincidentsinwhichanumberofsprinklersopenedandwaterdamageresulted.In1999theNFPAsprinklerprojectwasreorganized.ResponsibilitiesfortheearthquakeprotectionrulesweregiventoanewNFPATechnicalCommitteeonHangingand

13、BracingofWater-BasedFireProtectionSystems,oneoffourseparatetechnicalcommitteescoordinatedthroughaTechnicalCorrelatingCommitteeresponsibleforNFPA13.Thisallowedthedirectinputofmoreearthquakeengineeringexpertiseintothestandarddevelopmentprocess.Majorchangesinbuildingcoderequirementsforearthquakeprotect

14、ionhavetakenplaceinthepasttwentyyears,mainlyduetotheNationalEarthquakeHazardsReductionProgram(NEHRP)provisionsdevelopedwithfundingfromtheFederalEmergencyManagementAgency.TheNEHRPprovisionsinitiallyfoundtheirwayintothecodesthroughdirectadoption,andmorerecentlythroughreferencetotheAmericanSocietyofCiv

15、ilEngineer'sstandardASCE/SEI7.Asaresult,thegoalofthecommitteethatpreparesNFPA13hasevolvedduringtheyears.Fromtheoriginalgoalofindependentlyprovidingameansofprotectingsprinklersystemsagainstearthquakeforces,thecommitteeinrecentyearshasbeentryingtokeeppacewithamovingtargetassuccessiveeditionsofASCE

16、/SEI7addressprotectionofarchitecturalandmechanicalsystems.ThereisadifficulttransitionperiodtakingplacerightnowinvolvingtheseismicprovisionsofNFPA13andthe2003editionoftheInternationalBuildingCode?(IBC).BecauseofthereferencetoASCE/SEI7,the2003IBCdoesnotcontainthedetailedseismicrequirementsthathadbeeni

17、ncludedinthe2000editionofthe舊C.Althoughgeneralreferencetothe1999editionofNFPA13iscontainedinthe2003舊C,asectionofASCE/SEI7thatmadespecialreferencetotheuseofNFPA13forearthquakeprotectionwasomittedduringtheadoptionprocess,leadingsometobelievethatsprinklerpipingmustbeprotectedthesameasothermechanicalpip

18、ing.However,sprinklersystempipingisnotarrangedlikeothermechanicalpipingsystems,andsomeoftherulesofNFPA13havebeenspecificallydevelopedtopreventsystemdamageduringearthquakemovement.Forexample,whilemostmechanicalpipingsupportedbyhangerrodslessthan12in.(400mm)inlengthisexemptfrombracingundercurrentcodes

19、,comparativeexperienceofsprinklersystemswiththatexemptionversustheNFPAexemptionofonly6in(150m)wasprovidedbythe1987NewZealandearthquake.The2007StructuresCongress:NewHorizonsandBetterPractices?2007ASCECopyrightASCE2007StructuresCongress2007Downloaded06Mar2009toRedistributionsubjecttoASCElicenseorcopyr

20、ight;seeconclusionwasthatsystemsinstalledinaccordancewithNFPA13withstoodtheearthquake,whilethosenotsodesignedfailed.OverthepasttwodecadestherehavebeenanumerousrefinementsinthelanguageofNFPA13thatreflectthelessonslearnedinearthquakesaswellastheinfluenceoftheNEHRPprovisions.Thesecanbeevaluatedbylookin

21、gathowthevarioussectionsofNFPA13haveevolvedintwentykeyareas:ApplicabilityofNFPA13EarthquakeProtectionProvisions1983-Wheresubjecttoearthquakes1996-Whensprinklersystems-aretobeprotectedagainstdamagefromearthquakes1999-Wheresprinklersystemsorabovegroundfireservicemainsarerequiredtobeprotectedagainstdam

22、agefromearthquakes2002-Wherewater-basedfireprotectionsystemsarerequiredtobeprotectedagainstdamagefromearthquakesGeneralIntentofEarthquakeProtectionProvisions1983-Minimizeorpreventpipebreakage1991-Preventpipebreakage1999-ProtectagainstdamageFlexibleCouplings-General1983-Forpiping3?in.orlarger1994-For

23、piping2?in.orlarger;"Flexiblelistedpipecoupling"definedas"alistedcouplingorfittingthatallowsaxialdisplacement,rotation,andatleast1degreeofangularmovementofthepipewithoutinducingharmonthepipe”(minimum0.5degreesfor8-in.andlarger)2007-Flexiblecouplingsandclearanceidentifiedasaddressingdi

24、splacementduetostorydriftFlexibleCouplingsforRisersinMulti-StoryBuildings1983-Atceilingofeachintermediatefloor1994-Within12in.aboveandbelowthefloorinmultistorybuildingssuchthattheflexiblecouplingbelowthefloorisbelowthemainsupplyingthatfloor2007StructuresCongress:NewHorizonsandBetterPractices?2007ASC

25、ECopyrightASCE2007StructuresCongress2007Downloaded06Mar2009toRedistributionsubjecttoASCElicenseorcopyright;see1999-Within12in.aboveandwithin24in.belowthefloorinmultistorybuildings;Additionalcouplingrequiredonverticalportionoftie-inpipingwheretie-inisbelowtheupperflexiblecouplingontheriser2007-Additi

26、onalflexiblecouplingcanbeprovidedeitherontheverticalportionoftie-inpipingorwithin24in.onhorizontaltie-inpipingDropstoHoseLines,SprinklersinRacks,andPortionsofSystems1983-Fittingswithflexiblejointsatthetopofdropstohoselines(regardlessofsize);Swingjointsassembledwithflexiblefittingsondropstoracksover3

27、in.1987-Flexiblecouplingsatthetopofdropstohoselines(regardlessofsize);Swingjointswithflexiblefittingsondropstoracks(regardlessofsize)1989-Flexiblecouplingatthetopofdropstohoselines,racksprinklersandmezzanines(regardlessofsize);Flexiblecouplingatthetopofdropsexceeding15ft.tosprinklersorportionsofsyst

28、ems(regardlessofsize)1991-Flexiblecouplingwithin24in.oftheceilingattopofdropstohoselines,racksprinklersandmezzanines(regardlessofsize);Flexiblecouplingwithin24in.oftheceilingattopofdropsexceeding15ft.toportionsofsystemssupplyingmorethanonesprinkler(regardlessofsize)1994-Deleted"oftheceiling&quo

29、t;1996-Added"attopandbottom"ofdropssupplyinghoselines,racksprinklersandmezzanines2007-Additionalflexiblecouplingsfordropsrequiredwithinn24in.abovetheuppermostdropsupportor,wherenodropsupportisprovided,within24in.abovethebottomofthedropFlexibleCouplingsforExpansionJoints1983-Ononesideofbuil

30、dingexpansionjoints1987-Atornearbuildingexpansionjoints;Seismicseparationassemblyneededforseismicseparationjoints1999-Within24in.ofbuildingexpansionjointsSeismicSeparationAssemblies2007StructuresCongress:NewHorizonsandBetterPractices?2007ASCECopyrightASCE2007StructuresCongress2007Downloaded06Mar2009

31、toRedistributionsubjecttoASCElicenseorcopyright;see-Swingjointsassembledwithflexiblefittingsrequiredwherepipingcrossesseismicjoints;Figureaddedtoappendix1989-Addedaregardlessofsize”1991-Designatedas"seismicseparationassemblieswithflexiblefittings"Addedapplicabilityonly"abovegroundleve

32、l"2007-Expandedtoaflexiblefittingsorflexiblehose"andspecifiedminimumcapabilityofallowingmovementtoaccommodateclosingoftheseparation,openingofseparationtotwicenormalsize,andmovementrelativetotheseparationintheothertwodimensionsinanamountequaltotheseparationdistanceClearances1983-Clearanceth

33、roughwalls,floors,platformsandfoundations1in.allsidesthrough3?-inpipe,2in.allsides4-inchandlarger;Exceptionaddedtopermitpipesleevesofnominaldiameter2in.largerthrough3?-in.pipe(4in.largerfor4-inchandlargerpipe);Anotherexceptionaddedforpipepassingthroughgypsumboardorequallyfrangibleconstructionnotrequ

34、iredtohaveafire-resistancerating1985-Flexiblejointspermittedtosubstituteforclearanceforpipeenteringabasementwallwithgroundwaterconditions1987-Flexiblecouplingsorswingjointswithinonefootofbothsidespermittedtosubstituteforclearanceinanywall1994-Flexiblecouplingwithin1ft.ofeachsideacceptedasalternative

35、forwalls,platformsandfoundations2002-Clearancedimensionstobeconsiderednominal;Clearancenotrequiredforhorizontalpipingpassingperpendicularlythroughsuccessivestudsorjoiststhatformawall/ceilingassembly;Clearancenotrequiredfornonmetallicpipehavingflexibilityequaltoflexiblecouplingswithin1ft.ofbothsides.

36、SwayBracing-General1983-Pipingtobetiedtothestructureforminimumrelativemovement,butallowingforexpansion,anddifferentialmovementwithinandbetweenstructures;Topsofriserssecuredagainstdriftinginanydirectionusing4-waybrace1987-Zoneofinfluencemethodaddedtoappendixwithmaximumloadtablesforpipe,angles,rodsand

37、flatsbasedonthreerangesofanglefromverticalandmaximumslendernessratioof2002007StructuresCongress:NewHorizonsandBetterPractices?2007ASCECopyrightASCE2007StructuresCongress2007Downloaded06Mar2009toRedistributionsubjecttoASCElicenseorcopyright;see-Tableformaximumbraceloadsmovedtobodyofstandard1994-Syste

38、mpipingtobesupportedtoresistbothlateralandlongitudinalhorizontalloads1996-Systempipingtobesupportedtoresistbothlateralandlongitudinalhorizontalloadsandverticalloads;Eachrunofpipebetweenachangeindirectiontobeprovidedwithbothlateralandlongitudinalbracing;Exceptionforrunslessthan12ft.inlengthsupportedb

39、ybracesonadjacentruns;Tension-onlybracingallowediflistedfortheapplication2002-Clarificationthat4-waybracingisrequiredatthetopsofrisersexceeding3ftinlength;Maximumverticaldistancebetween4-waybraceslimitedto25ft2007-BracesandrestraintsidentifiedaspossibleobstructionstosprinklerdischargeSwayBracing-Loa

40、ds1983-Swaybracingtowithstandaforceintensionorcompressionequivalenttonotlessthanhalftheweightofwater-filledpiping1989-Assignedloadtableadded.Alternativepermittedforzoneofinfluencemethod:Forlateralbraces-allbranchlinesandmainswithinzoneForlongitudinalbraces-allmainswithinzone1994-Multiplierspermitted

41、forhorizontalforcefactorFp=0.5WpwhereuseofotherforcefactorsrequiredorpermittedbyAHJ1996-"Whenthehorizontalforcefactorusedexceeds0.5Wpandthebraceangleislessthan45ofromverticalorwhenthehorizontalforcefactorusedexceeds1.0Wpandthebraceangleislessthan60ofromvertical,thebracesshallbearrangedtoresistt

42、henetverticalreactionproducedbythehorizontalload"1999-Assignedloadtabledeleted2002-Factorof1.15Wptobeusedtoaccountfortheaddedweightoffittings,valvesandotherdevices2007-Tableincludedof"SeismicCoefficients"toallowdeterminationofhorizontalseismicloadsbasedonmappedvaluesofshortperiodrespo

43、nseparameterSS;Seismiccoefficienttobe0.5wherenospecifiedbytheAuthorityHavingJurisdiction;Loadsinallowablebraceloadtablereducedbyfactorof1.4tobringintolinewithallowablestressapproachSwayBracing-LongitudinalBraces2007StructuresCongress:NewHorizonsandBetterPractices?2007ASCECopyrightASCE2007StructuresC

44、ongress2007Downloaded06Mar2009toRedistributionsubjecttoASCElicenseorcopyright;see-Braceforfeedandcrossmains;Lateralbracesmayactaslongitudinalifwithin24in.ofcenterlineofpipingbracedlongitudinally1987-Longitudinalbracingrequiredatmaximum80ft.oncenter1994-Omissionoflongitudinalbracespermittedforpipessu

45、pportedbyrodslessthan6inchesinlength1996-Deletionof6-inchrodexemptionforlongitudinalbraces1999-Longitudinalbracerequiredwithin40ftoftheendofamainSwayBracing-LateralBraces1983-Lastlengthofpipeatendoffeedorcrossmaintobeprovidedwithlateralbrace;Appendixfiguresshowlateralbraces"about40ft.”1985-Late

46、ralbracingatmaximum40ft.centers1989-Maximumspacingto50ft.whenbuildingprimarystructuralmembersexceed40ft.oncenter1996-Distancebetweenlastbraceandendofpipelimitedto20ft.(25ftwherebracesupto50ft.o.c.);Longitudinalbracespermittedtoserveaslateralbraceswhenwithin24inofcenterlineofpipingbracedlaterally2007

47、-Tableaddedtoallowmaximumloadperbracebasedonspacingfrom20ftto40ftalongwithsizeandtypeofpipe;Allowanceformaximumspacingover40fteliminated;Distancebetweenlastbraceandendofpipelimitedto6ftSwayBracingforExcessiveFlexibility1983-Aswaybracerequiredwithin24in.offlexiblecouplingsusedotherthanforearthquakepr

48、otection1989-Alateralbracerequiredwithin24in.ofeveryother(such)coupling,butnotmorethan40ft.oncenterShortHangerExceptiontoBracing1983-Swaybracingmaybeomittedwhenhangerrodslessthan6in.longareused1985-Movedtobecomeexceptiontorequirementforlateralbracing1994-Allowedforoneeditiontoalsoapplytolongitudinal

49、braces(repealedin1996)2007StructuresCongress:NewHorizonsandBetterPractices?2007ASCECopyrightASCE2007StructuresCongress2007Downloaded06Mar2009toRedistributionsubjecttoASCElicenseorcopyright;see-ClarifiedthatlengthofhangerrodismeasuredbetweentopofpipeandthepointofattachmenttothestructureBracing/Restra

50、intofBranchLines1987-Swaybracingnotrequiredforbranchlines;Exceptionrequiresrestraintofendsprinkleronlineagainstexcessivemovementbywrap-aroundU-hookorotherapprovedmeans1989-Secondexceptionaddedtorequirelateralbracingforbranchlines2?in.orlarger1991-Thirdexceptionaddedtorequirewrap-aroundU-hook,lateral

51、ervalswithin2ft.ofhangerwhereupwardorlateralmovementofsprinklerswouldresultinimpactagainstbuildingstructure,equipmentorfinishmaterials1994-Sprig-upsexceeding8ft.inlengthtoberestrainedagainstlateralmovement1996-Sprig-ups4ft.orlongertoberestrainedagains

52、tlateralmovement1999-Restraintclarifiedtobe"alesserdegreeofresistingloadsthanbracing"U-hooksusedtosatisfyrequirementsforrestraintrequiredtohavelegsbentout30ofromvertical2007-Exceptwherebranchlinesaresupportedbyrodslessthan6in.(150mm)inlength,restraintofallbranchlinesisrequired,withmaximumd

53、istancebetweenrestraintsrangingfrom27to55ft(8.2to16.7m)dependingonthesizeofthebranchlineandtheforcelevel;Additionalhangeratminimum45-degreeanglefromverticalcanbeusedasrestraintifslendernessratiodoesnotexceed300Ceiling/SprinklerInteraction1983-Minimizeorpreventpipebreakage1991-Preventpipebreakage;For

54、branchlines,restraintrequiredwithin2ftofhangersatmaximum30-ftintervalswhereupwardorlateralmovementofsprinklerswouldresultinimpactagainstbuildingstructure,equipmentorfinishmaterials2002-Clarificationofintenttopreventdamagetosprinklers,nottopreventimpactSwayBracing-BraceComponents1983-Swaybracingtobed

55、esignedtowithstandaforceintensionorcompression1985-Forindividualbraces,theslendernessratiol/rlimitedto200see-2007StructuresCongress:NewHorizonsandBetterPractices?2007ASCECopyrightASCE2007StructuresCongress2007Downloaded06Mar2009toRedistributionsubjecttoASCElicenseorcopyright;Maximumlengthloadtablesa

56、ddedtoappendixbasedonthreerangesofanglefromvertical1989-Maximumlengthandloadtablesmovedfromappendixtobodyofstandard1994-Allowableslendernessratioincreasedto3001996-Swaybraceassembliesrequiredtobelistedforamaximumallowableload;Loadstobereducedpertableforangleslessthan90ofromvertical;Wherepipe,angles,

57、flatsorrodsusedasbraces,exceptiontorequirelistingofbracefittingsandconnectionsonly;Anotherexceptiontopermittension-onlybracingsystemswhenlistedforthisserviceandinstalledinaccordancewithlistinglimitation;ThreadedpipeusedaspartofaswaybraceassemblytobenotlessthanSchedule30;Appendixmaterialaddedtorecomm

58、endswaybracemembersbecontinuous,butthatwheresplicesarenecessarytheyshouldbedesignedandconstructedtoensurethatbraceintegrityismaintained1999-SampleformsaddedtoappendixtoassistinbracecalculationsU-HooksasSwayBraces1983-U-typehangerssatisfybracingrequirementsexceptlongitudinalbraceneededfor2?-inandlarg

59、erpiping;U-typehangersusedaslateralbracestohavelegsbentat10degreesfromvertical1987-U-typehangerssatisfyrequirementsforlateralswaybracing1991-Wrap-aroundU-typehangerspermittedaslateralswaybracingprovidedlegsarebentout30degreesfromverticalandslendernessratiocriteriasatisfied1996-AllowanceextendedtoU-t

60、ypehooksarrangedtokeepthepipetighttotheundersideofthestructuralelementSwayBracing-FastenerstoStructure1983-Pipenottobefastenedtobuildingsectionswhichwillmovedifferently1987-C-typeclamps(withorwithoutretainingstraps)prohibitedfrombraceattachment;Fastenerloadtablesaddedtoappendixbasedonsixorientation/angleconditions1989-Fastenerloadtablesmovedfromappendixtobodyofstandardandexpandedtonineorientation/anglecondi