Post on 02-Jun-2018
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Plant-Cast Precast Concrete% Concrete elements, cast and cured in a manufacturing plant,
then transported to the construction site!
% lant casting allo's increased e(ciency and higher )ualitycontrol!% *ura+le, permanent steel forms are reused many times, reducing
form'or costs compared to sitecast concrete!% -se of .ype """, high early strength cement and steam curing
allo' concrete mem+ers to +e cast and cured in as little as 2/hours!
% Controlled casting conditions and high )uality forms allo' forgreater control of surface nishes!
5 PRECAST CONCRETE FRAMING SYSTEMS
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lant1Cast recastConcrete
%tructural elementsare commonlyreinforced 'ithtightly stretchedpretensioned steelstrands, 'hich
pro$ide increasedstructural e(ciency!
% Con$entional steelreinforcing is addedfor resistance tothermal and othersecondary stresses!
5 PRECAST CONCRETE FRAMING SYSTEMS
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lant1Cast recastConcrete
% 3n the constructionsite, precastconcrete elementsare lifted into placeand assem+led intostructural assem+lies
in a process similarto that used forstructural steel!
% Compared to sitecastconcrete, precast
concrete erection isfaster and lessa4ected +y ad$erse'eather conditions! # $acuum lifting de$ice is used to lift and place
precast concrete prans!
5 PRECAST CONCRETE FRAMING SYSTEMS
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5 PRECAST CONCRETE FRAMING SYSTEMS
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recast Concrete la+s
% -sed for 8oor and roof decs!
% *eeper elements to'ard theright +elo': span further thanthose that are shallo'erto'ard the left:!
% Right: ;ollo' core sla+s
staced at the precasting plant!
PRECAST, PRESTRESSED CONCRETE STRUCTURAL ELEMENTS
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recast Concrete Beams and
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recast ConcreteColumns and >allanels
% ro$ide support for+eam and sla+elements!
% ince these elementscarry mainly a?ialloads 'ith little+ending force, theymay +econ$entionallyreinforced 'ithoutprestressing!
% 3r, long, slendermultistory elements
may +e prestressedto pro$ide resistanceto +ending forcesduring handling anderection (columns atright).
PRECAST, PRESTRESSED CONCRETE STRUCTURAL ELEMENTS
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recast Concrete Columnsand >all anels
% recast concrete 'all
panels may +e solid (right:,hollo', or sand'iched'ith an insulating core:!
% >all panels can +e ri++ed,to increase their $erticalspan capacity 'hileminimi@ing 'eight, orformed into other specialshapes (below)!
PRECAST, PRESTRESSED CONCRETE STRUCTURAL ELEMENTS
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3ther recast ConcreteElements
%recast concrete stairsbelow)
% -ni)uely shaped structuralelements for a sportsstadium (right)
% Etc!
PRECAST, PRESTRESSED CONCRETE STRUCTURAL ELEMENTS
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#ssem+ly Concepts forrecast ConcreteBuildings
% Aertical support can +epro$ided +y precastcolumns and +eamsabove:, 'all panelsbelow:, or acom+ination of all
three!% .he choice of roof and8oor sla+ elementsdepends mainly onspan re)uirements!
% recast sla+ elements
are fre)uently alsoused 'ith other $erticalload+earing systemssuch as sitecastconcrete, reinforcedmasonry, or steel!
PRECAST, PRESTRESSED CONCRETE STRUCTURAL ELEMENTS
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#ssem+ly Concepts forrecast ConcreteBuildings
% Above:recastconcrete structureconsisting of solid'all panels andhollo' core sla+s!
% Below: # single story'arehouse consistingof dou+le teessupported +yinsulated sand'ich
'all panels!
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#ssem+ly Conceptsfor recastConcreteBuildings
% # paring garagestructureconsisting ofprecast dou+letees supported+y in$erted tee+eams onhaunchedcolumns!
PRECAST, PRESTRESSED CONCRETE STRUCTURAL ELEMENTS
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Casting ;ollo' Corelans
% recast elements aremanufactured incasting beds, 00 ftor more in length!
% ;igh1strength steelstrands are strung
the length of the +edand tensioned!
% Con$entionalreinforcing, 'eldplates, +locouts,
lifting loops, andother em+eddeditems are added asneeded!
% Concrete is placed!
MANUFACTURING OF PRECAST CONCRETE STRUCTURAL ELEMENTS
-ntensioned prestressing strands can +e seen inthe left1most casting +ed! "n the +ed second fromthe right, lo'1slump concrete for hollo' coresla+s is +eing formed o$er tensioned strandsusing an e?trusion process! # completed hollo'core casting is $isi+le at the far right!
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restressing andeinforcing teel
% Many precastelements contain+oth prestressingstrands andcon$entionalreinforcing!
% Right:.heprestressing strandsfor an ##;.3 girderare depressed into ashallo' $1shape tomost e(ciently resist
tensile forces in the+eam! hear stirrupsare formed fromcon$entional steelreinforcing!
MANUFACTURING OF PRECAST CONCRETE STRUCTURAL ELEMENTS
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Casting ;ollo' Corelans
% 3nce the concretehas cured to su(cientstrength, the castingsare cut into sectionsof desired length(above)!
% "n some cases,trans$erse +ulheadsare inserted to di$idethe casting +ed intosections +eforeconcrete is placed! "n
this case, only theprestressing strandsneed to +e cut toseparate the sections(below).
MANUFACTURING OF PRECAST CONCRETE STRUCTURAL ELEMENTS
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Casting ;ollo' Corelans
% "ndi$idual sectionsare lifted from thecasting +ed (right)and stocpiled toa'ait shipping tothe constructionsite!
MANUFACTURING OF PRECAST CONCRETE STRUCTURAL ELEMENTS
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Casting ;ollo' Corelans
% recast concreteelements areshipped to theconstruction site +ytruc and erectedon site +y crane!
MANUFACTURING OF PRECAST CONCRETE STRUCTURAL ELEMENTS
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Casting ;ollo'Core lans
% ample hollo'core sla+sections of$aryingdepths!
%#t +ottom left,note theinsulatedsand'ich 8oorpanel!
MANUFACTURING OF PRECAST CONCRETE STRUCTURAL ELEMENTS
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5 PRECAST CONCRETE FRAMING SYSTEMS
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E?ample Column1to1Column Connection% Metal +earing plates and em+edded anchor +olts are cast into
the ends of the columns!
% #fter the columns are mechanically =oined, the connection isgrouted to pro$ide full +earing +et'een elements and protectthe metal components from re and corrosion!
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E?ample Beam1to1ColumnConnection
% Beams are seton +earingpads on thecolumncor+els!
% teel anglesare 'elded tometal platescast into the+eams and
columns andthe =oint isgrouted solid!
JOINING PRECAST CONCRETE ELEMENTS
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itecast Concrete.oppings o$errecast la+s
%
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recast ConcreteConstruction andeismic *esign
% "n areas of highseismic ris,structures must +edesigned torespond safely tothe dynamic forcesimparted into thestructure!
% "nno$ations in =ointdesign areimpro$ing theconnectionsystems in precast
concrete structuresand maing themincreasinglysuita+le for use insuch areas!
JOINING PRECAST CONCRETE ELEMENTS
# large scale test facility for simulating seismicforces on precast concrete structural systems!