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transformations[90].Geometricalandmaterialrestrictionsrelatedtothe
effectiveshapetransformationsaretakenintoaccountinthepresentmonograph.
Sotheireffortwouldbeassmallaspossible[32,89,91].Themethodconsistsin
seekingfortworulingsmodellinglongitudinaledgesofeachshellfold,
intersectingtheroofdirectrices,sothatthesupportingconditionsevaluatedfor
thefoldcorrespondtothepossiblesmallitsstresses[91].
Forthatpurpose,AdamReichhartdefinedthreekindsoftheeffectiveshape
transformationsthatare:
a)freetransversalbendingdeformation,Fig.2-1a,
b)freetorsionaldeformation,Fig.2-1b,
c)freebending-torsionaldeformation,Fig.2-1c.
Inpractice,hehasemployedonlythefreetorsionaldeformationand
proposed:
a)tosubstitutetwolinessupportingthebothcrosswisefold’sendsbytwo
skewstraightsegments,
b)centralsectorsofrighthyperbolicparaboloidsasgeometricalmodelsfor
eachcompletefoldslocatedintheshellroof[90,91].
Fig.2-1.Threetypesoftheeffectivetransformations:a)free
transversalbendingdeformation;b)freetorsionaldeformation;c)free
bendingandtorsionaldeformation
Thus,accordingtotheReichhart’sconcept,asectorofageneralwarped
surfacecanbeadoptedasamodelofanyshellcorrugatedroof.However,as
welltheexactshapeofthesectorasthemathematicequationofthesurfacein
whichthesectorisdistinguishedcannotbefoundwiththehelpofhismethod.In
