板式楼梯梯板厚度确定The thickness of the plate staircase is determineddoc.docx
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板式楼梯梯板厚度确定The thickness of the plate staircase is determineddoc.docx
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板式楼梯梯板厚度确定Thethicknessoftheplatestaircaseisdetermineddoc
板式楼梯梯板厚度确定(Thethicknessoftheplatestaircaseisdetermined)
[collectionofdocuments]:
thethicknessoftheplatestaircaseisdetermined
Thethicknessoftheplatestaircaseisdetermined
Time:
Theplatethicknessoftheboardis1/25~1/30l,andthenetstepoftheboardstairis4M,butmanyframestructuresarelargerthan4M,andhowshouldthethicknessoftheplatebedetermined?
(onlysteponthesideoftheladderbeam,andontheothersideoftherestplatform)
ASA:
Accordingtotheactualplatespanof1/25,ifthethicknessoftheplateisgreaterthan250mm,itisindicatedthatthestructureplanischanged
HHH:
Itissaidthat"thenetstepoftheboardstair"ismainlyfromaneconomicpointofview,andtheactualprojectis6meterscommon.Whenthespanislarge,thethicknessoftheboardismainlycontrolledbydeflection,and1/25-1/30lisreasonable
Newx:
A3,600-spanstaircase,thethicknessoftheboardshouldbemadeof140,seemsalittletoothick,
Thefollowingisattachedwiththeslidebookofthetable:
tb-2
I.basicinformation:
Projectname:
project1
Thestairstype:
platetypeA(╱)bearingcondition:
elasticonbothends
ThehorizontalprojectionlengthoftheladderisLo1=3600mm,whichisequaltoLo1=3600mm
NetwidthofladderplateB=1200mm
Slabthicknessh1=140mm
HeightHv=1500mmstaircaseseriesn=10
Lowersupportwidthd1=200mmuppersupportwidthd2=200mm
LinearconstantloadPk=0.00kN/m
Uniformliveloadqk=3.00kN/mbitsofc=0.7bitsofq=0.6
Thicknessofsurfacelayerc1=25mmceilingthicknessc2=20mm
Surface,ceilingdensitygammac=20.00kN/mstairweightdensitygammab=25.00kN/m
Strengthgradeofconcrete:
C25
Fc=11.94ft=1.27FTK=1.78N/mmEc=27871N/mm
Steelbarintensitydesignvaluefy=210n/mmEs=210000n/mm
Thelongitudinalreinforcementpointstothenearedgedistanceas=25mm
2.Calculationresults:
1.Stairgeometryparameters:
Stepheightt=Hv/n=1500/10=150.0mm
Stepwidthw=Lo1/(n-1)=3600/(10-1)=400.0mm
BenchrampAnglealpha=ArcTan(t/w)=ArcTan(150.0/400.0)=20.6°
LaddersectionofthelengthoftheinclinedplateLx=Lo1/cosinealpha=3600/Cos20.6°=3845mm
Ladderplatethicknesstotheverticalheightoftheh1'=h1/cosinealpha=140/Cos20.6°=150mm
T=(T+2*h1')/2=(150+2*150)/2=225mm
Ladderplateeffectiveheight:
h1o=h1-as=140-25=115mm
2.Loaddesignvalue:
(1)standardvalueoftheuniformlydistributedvalue:
1.
Gk1=gammab*T=25.00*0.225=0.225kN/m
2.
Gk2=gammac*c1*[n*t+(n-1)*w]/Lo
[=20.00*0.025*10*0.150+(10-1)*0.400]/3.600=0.71kN/m
Thetopoftheceiling:
gk3'=gammac*c2=20.00*0.020=0.40
Lx/Lo==gk3'gk3*0.40*3.845/3.600=0.43kN/m
Gk=gk1+gk2+gk3=6.75kN/m
(2)designvalueofuniformlydistributedload:
Controlledbytheliveloadloaddesignvalueofp(L)=1.2+1.4**gkqk=12.30kN/m
Byconstantloadcontrolloaddesignvalueofp(D)=1.35+1.4**gkbitsofc*qk=12.05kN/m
Themostunfavorableloaddesignvalueofp=Max{p(L),p(D)}=12.30kN/m
3.Calculationofshearbearingcapacityofobliquesection:
Vmaxislessthanorequalto0.7*ft*b*ho
VmaxLo*cosinealpha==0.5*p*0.5*12.30*3600*Cos20.6°
=22137*0.9363=20727n
7*ft*b*ho=0.7*1.27*1000*115=102311N
VMax=20727N,meettherequirements.
4.Calculationofbendingbearingcapacityofnormalsection:
CalculatespanL=Min{Lo+(d1+d2)/2,1.05*Lo}
=Min{3800,3780}=3780mm
AcrosstheMmax=p*L^^2/10=12.30*12.302/10=17.572kN·M
As=541mmrho=0.47%
(Ⅱ)Φ12@175(As=646)
BearingMmin=p*L^^2/24=12.30*12.302/24=7.322kN·M
As=311mmrho=0.27%rhomin=As*=381mm0.27%
Phi10@170(As=462)
5.Cross-mediumdeflectioncalculation:
Mk--thebendingmomentvaluecalculatedaccordingtothestandardcombinationoftheloadeffect
Themomentvalueofthequasi-permanentcompositecalculatedbytheloadeffect
(1)parametersofdeflectioncalculation:
Mk=13.93kN·MMq=12.21kN·M
(2)underthecombinationofthestandardcombinationoftheloadeffect,theshort-termstiffnessofthebendingmember:
1.Thedifferentialcoefficientoftensionofthelongitudinaltensilesteelreinforcementiscalculatedaccordingtothefollowingformula:
Psi=1.1-0.65*FTK/rhote/sigmask(concretespecification8.1.2-2)
Sigmask=Mk/0.87/ho/As(concretespecification8.1.3-3)
Sigmask=13929097/0.87/115/646=215n/mm
Rectangularcrosssection,Ate=0.5*b*h=0.5*1000*140=70000mm
Rhote=As/Ate(concretespecification8.1.2-4)
Rhote=646/70000=0.92%
Psi=1.1-0.65*1.78/0.00923/215=0.518
Theratiooftheelasticmodulusofthesteeltotheconcretemodulusis
AlphaE=Es/Ec=210000/27871=7.53
Theratioofthecompressionflangeareatotheeffectiveareaoftheabdominalplategammaf':
Therectangularcrosssection,gammaf'=0
TheratioofsteelreinforcementtolongitudinaltensilereinforcementisequaltoAs/b/ho=646/1000/115=0.00562
TheBsofthebendingmemberofthereinforcedconcreteiscalculatedbytheformula(8.2.3-1ofconcretespecification):
Bs=Es*As*ho^2/alpha[bitsof1.15+0.2+6*E*rho/(1+3.5gammaf')]
Bs=210000*646*115m^2/[*0.518+0.2+1.15
6*7.53*7.53/(1+3.5*0.000)]=1708.86kN·M
(3)consideringtheinfluenceoflong-termeffectcombinationofloadonthedeflectioninfluencecoefficienttheta:
Accordingtosection8.2.5ofconcretespecification,whenrho'=0,theta=2.0
(4)thelong-termstiffnessBoftheflexuralmembercanbecalculatedaccordingtothefollowingformula:
B=Mk/[Mq*(theta-1)+Mk]*Bs(concretespecification8.2.2)
B=13.93/[(2-1)+12.21*12.21]*1708.86=910.47kN·M
(5),midspandeflectionf=3.0/384*Qk*L^4/Bl
F=0.00781*9.75*9.75*1000=^4/910.4717.1mm
F/Lo=1/211
Waterdrop.
Iwouldliketoaskyou,arethestairstairsuitableforthedesignofbothends?
Shouldconsiderthefixedendeffect,fromthetextbookformulas:
M=QL2/10canbeseen,soIcalculatemorecommonlyiscalculatebyelasticandincreasebearingreinforcementinreducingcrosstodetermine,Iusuallytake1/30forladdersectionthickness,thatisenough,thereisnoneedtobig.
Wj4112:
Howmuchthicknessisrelatedtotheloadsize.Wemadethestairs4kpaliveload,spanof5.8meters,thethicknessof250,spanandlargeit'sverydifficult.1/25~1/30isonlyreference,asageneralrule,thelargerthespan,thegreaterthethicknessgrowth.Usuallybeamaccordingtotheapproximatehinge(1/10),accordingtothestructurewithplateofnegativemomentreinforcementandliangofthetorsionbar,thereisnoneedtocalculatedaccordingtothefixedend.Infact,accordingtothefixedendcalculatingreinforcementinsteadbeunsafe,soisinsufficientbendingofreinforcement,negativebentbarusuallywon'tpullthrough,internalforceredistributioneffectislimited.
Wwily:
Thestairinclinedboardiscalculatedbytwoendsconsolidationcalculationisunfavorable,alsodidnotseewhatbooksocalculate
Thepreviousteachingmaterialwastotake1/10oftheslantingboard,whichwastosaythattheconstraintofthesupportwasconsidered,butsomeofthenewtextbookshadbeenchangedto1/8,whichispureandsimple.Thereasonissimple,thespanofthestairs,thegreatertherestrictioneffectbetweentheplateandbeam,themoreobvious,calculatedon1/10,forsmallspanboard,isthoughttobelessthan3metersisnotconsideredbefore,butnowcommonplatestairsspanlarger,wascalculatedat1/10,soyoushouldconsiderbeamsubjectedtotorsion.Becausethefieldtripfoundalotofcracksintheboard,resultinginthedecorationcracking.
Boardspan1/25~1/25,wegenerallytake1/30,becausestairrampisdifferentfromgeneraltablet,southeastuniversityhasbeenpublishedinjournalofbuildingstructuresridemanwouldbeanexperimentalresults,whichconsidertheladderboardsawtootheffectonthedeflection,provethatladderplatedeflectionismoreabundant.
Goodwill:
It'sverycommontohavealevelofover4m,
Aregenerallymadeofplate,theplatethicknessisgenerally1/30.Alsodidn'tseewhat'stheproblem,thebeamendconsolidationeffectisgenerallyconsidered,becauseIwasthetextbooksarewrittenso,calculateby1/10frombending,actualreinforcementisbigontheboardandboardband,issupposedtobeunreasonable,butwithbiggercancontrolcracks,sohasbeendesignedinthisway.
Yxm:
Whentherestplatformandfloorpanelconnectedwiththeladderbeamareinthepresentcasting,theladlesupportshallbeelastic,andtheladleshallbethick
T=ln/25~ln/30,lnisthehorizontalprojectionlengthoftheladder.
JGJG:
Theactualreinforcementisundertheboardandtheboardisthesamesize,shouldbeunreasonable,butthebiggerpointcancontrolthecrack,sothedesignisalwaysso.
Thisisalsoaproblemforme,thankyou!
Scoobydoo:
Morethan4msuitableforgirderstairs,thestructureisreasonable,andthebroker
Nhlyk:
Ialsothinkthethicknessoftheplateis1/30.
flysky2004
PleasesupportMmin=p*L^2/24howcome?
stirrup
Ithinkitshouldbeonbothsidestoconsiderasisconsolidation,sowillgetP*L^2/24
QNXX
Platethicknessismainlydeflectioncontrol(calculatedaccordingtoMorgain)
yaokd
Thedeflectionoftheboardstairisnotfoundinthegeneralbookdata,thethicknessoftheplatewillbeverylargeaccordingtothegenerals
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