Longitudinal FramingSystemResulted from need for morelongitudinal strength as ships becamelarger All supporting structure runs in thelongitudinal directionSystem of “girders” and “longitudinals' Girders main role is to carry long'I loadlongitudinals are “beam-columns" in thatthey perform two roles -supporting plating against hydrostatic pressurecarryinglongitudinalloads
l Resulted from need for more longitudinal strength as ships became larger l All supporting structure runs in the longitudinal direction l System of “girders” and “longitudinals” Ø Girders main role is to carry long’l load Ø longitudinals are “beam-columns” in that they perform two roles - ² supporting plating against hydrostatic pressure ² carrying longitudinal loads
Longitudinal Framing SystemTransverseFrame:7ffubqfLongitudinalGirder:LongitudinalgthgStiffener:Igw
Longitudinal Stiffener: Longitudinal Girder: Transverse Frame:
Longitudinal Framing SystemLORGITUDINALDECK GIRDERSITYPICALLOIGITUDINALBEAMSTRAISVERSEWEBFRAHESIAINDECKSECONDDECKSTRINGERTYPICALLONGITUDINALBEAMlu.S.Navy ships do not uve girders; insead, morenumerousstanchionsareuscdLONGITUDINAL GIRDERS2U.S. Navy ships without an innerbottom have asinglekeelson or longitudinal (girder),in way of thebilgedockingblocks
Longitudinal FramingSystemAdvantagesVery efficient use of material> Sound engineering approach for vessels ofall sizesCheaperforlargevesselsDisadvantagesLargewebframes makestowage of bulkcargoes difficult> Large frames make for difficultaccessibility, routing of piping, cabling, etc
l Advantages Ø Very efficient use of material Ø Sound engineering approach for vessels of all sizes Ø Cheaper for large vessels l Disadvantages Ø Large web frames make stowage of bulk cargoes difficult Ø Large frames make for difficult accessibility, routing of piping, cabling, etc
Combination Framing SystemSensible use of the best of the otherframing systems> Decks and bottom are longitudinallyframedSides and long'l bulkheads aretransversely framed.Why?> Largest bending stresses in the deck &bottomTransverselyframed sides allowsforsmallerframes-more cargo space
l Sensible use of the best of the other framing systems Ø Decks and bottom are longitudinally framed Ø Sides and long’l bulkheads are transversely framed l Why? Ø Largest bending stresses in the deck & bottom Ø Transversely framed sides allows for smaller frames - more cargo space