Folded Plate structures

Folded Plate structures

1. FOLDED PLATE STRUCTURES
Rohan Joshi -Assignment 4

2. Folded plate structures
Foldedplatesareassembliesofflatplatesrigidlyconnectedtogetheralongtheiredgesinsucha
waythatthestructuralsystemcapableofcarryingloadswithouttheneedforadditional
supportingbeamsalongmutualedges.
Modernfoldedplatestructuresaretypicallymadeofcastinsituorprecastreinforcedconcrete,or
steelplate.
Thereareseveralbenefitsoffoldedplateconstruction.Theyaresimplertomanufacturethan
othershellssuchascylindricalshells,withrelativelysimpleformworkrequired,andusuallyuse
lessmaterial.However,foldedplatesrequiremorematerialsthancurvedshellssincethereis
normallymorebendinginvolved.
Foldedplatestructureshaveanintrinsicrigidityandhighload-carryingcapacitywhichmakes
themeconomicaloverlongspansthatneedtobefreeofinternalcolumnsandotherobstructions.

3. FOLDING SYSTEMS IN NATURE
Theprincipleoffoldingasatooltodevelopageneralstructuralshapehasbeenknownfora
longtime.Foldedstructuresystemswhichareanalogoustoseveralbiologicalsystemssuchas
foundatbroadleaf-treeleaves,petalsandfoldableinsectwings,areadoptedtobeemployed
inanew,technicalway.LeafofPalmTreeBeetleInsectWithFoldableWingsSeashell
THE PRINCIPLE OF FOLDING
The structural characteristics of
folding structures depend on:
•The pattern of the folding.
•Their geometrical basic
shape.
•Its material.
•The connection of the
different folding planes.
•The design of the bearings.
•Movable form work can be
employed.
•Form work required is
relatively simpler.
•Design involves simpler
calculations.

4. STRUCTURAL BEHAVIOR OF FOLDING
StructuralConditionOfFoldingStructuresLoad
Distributionprocess:
•Atfirst,theexternalforcesaretransferredto
theshorteredgeofonefoldingelement.
•There,thereactionasanaxialforceisdivided
betweentheadjacentelements.
•Thentheforcestransferredtothebearings.

5. TYPESOFFOLDEDSTRUCTURE
Basedongeometricshapefolded
structurescanbedividedinto:
•foldedplatesurfacesstructures:
oprismatic:rectangularplates.
opyramidal:non-rectangularplates.
oprismoidal:triangularortrapezoidal
plates
•foldedplateframesstructures
•spatialfoldedplatestructures
Geodesic Dome TaperedFoldedPlates
Folded plate rigid frames

6. BASICELEMENTSOFFOLDEDPLATES:
•TheInclinedPlates.
•Edgeplateswhichmustbeusedtostiffenthewideplates,
•Stiffenerstocarrytheloadstothesupportsandtoholdtheplatesinline.
•Columnstosupportthestructureintheair.
TAPEREDFOLDEDPLATES:
Foldedplatestructuresmaybebuiltwithtaperedelementsandonlyoneofthemany
possiblecombinationsisshownhere.
Theheightoftheshellsatthecenterofthespanisthecriticaldimensionforbending
strength.therefore,thestructureisnotveryefficientandnotsuitableforlongspans
becauseoftheexcessheightrequiredforthelargeends.
Anotherweakelementinthisdesignisthetransferofshearfromthesmallendofthe
triangularplatetothelargeend.ifalargenumberofunitsareusedineachspan,the
transferofloadsmaybedifficult.
Afoldedplatemaybeusedforwallsasathinstructuralelementbycastingeachplateflat
onthefloorandgroutingthejointsfullofconcrete.awallofthistypecanbemademuch
thinnerthanaflatwall.

7. FOLDEDPLATETRUSS:
•Theterm"foldedplatetruss"isintendedtoindicatethestructuralactionofthisstructure.
Therearehorizontaltiesacrossthewidthonlyattheendsofthebuilding.
•Thethrustsfromthetriangularcrossedarchesarecarriedlengthwisetotheends.
•Thetopchordoftheinclinedtrussisformedbytheridgemember.
•Thebottomchordsarethetiesatthebaseofthesidegablesandthediagonalsareformed
bytheslopingvalleysattheintersectionofthegablesandthetriangularplates.
•Thisistrulyaspacestructureanditsstructuralactionisasshownand,therefore,the
architecturalappearanceismotesubtlethattheusualshellstructure.
FOLDEDPLATERIGIDFRAME:
•AnarchwithstraightsegmentsissometimescalledaRigidFrame.
•Itisnotasefficientasthecurvedarchbecausethebendingmomentsaregreater.
•Tiesacrosstheplatesarerequiredatthekneesandatthecrowninordertodistributethe
forcesattheendsofeachsegment.

8. EDGESUPPORTEDFOLDEDPLATES:
Theusualupturnededgeplatecanbeeliminatedandtheroofstructurecanbemadeto
appearverythiniftheedgeplateisreplacedbyaseriesofcolumns.
Theslabbetweencolumnsmustbedesignedasabeamanditmaybeconvenienttoextend
themainroofslabasaCantileverCanopy.
Thebeamelementthatcarriestheloadoftheroofbetweencolumnswillthenbewiderand
windowsundertheslabwillhavethesamefunctionasinthepreviousexamplesoffolded
plates.
Notetheverticalcolumnsintheendwallsatthecrownofthegable.thesetakethereactions
oftheplatesandthehorizontaltiesmaybeeliminated.windloadsaretakenbyrigidframe
actionintheColumnsandStiffeners.
THREESEGMENTFOLDEDPLATE:
Theforcesfromthereactionsoftheslopingplatesontheserigidframeswillbequirelarge
andatanoutsidecolumntheywillnotbebalancedbythrustsfromtheadjacentplates.
Thesizeoftheframesmaybereducedbyusingasteeltiebetweenthetopsofthecolumns
whichcanbeconcealedinthefenestration.Thedimensionsoftheplatesaredependenton
boththewidthofthebarrelandonthespan.
Thedepthoftheshellshouldbeabout0.10timesthespanandthemaximumslopeofaplate
shouldnotbegreaterthan40degrees.

9. APPLICATIONSOFFOLDEDPLATESTRUCTURES
As a roof, Sport’s Gymnasium, Brazil As a wall, Air force Academy Chapel, Colorado
As a floor structure, floor decking As sheet piles, securing the foundation pit

10. References
•https://www.slideshare.net/RohanNarvekar2/folded-plates
•https://www.researchgate.net/publication/281395871_Folded_structures_in_modern_architec
ture
•https://structurae.net/en/structures/buildings/folded-plate-structures
•https://encyclopedia2.thefreedictionary.com/Folded+Plate+Structure
•https://www.designingbuildings.co.uk/wiki/Folded_plate_construction#:~:text=Folded%20pl
ate%20structures%20are%20assemblies,supporting%20beams%20along%20mutual%20ed
ges.