Rules for the Classification of Floating Docks - Boat Design Net

Chapter 4Figure 5Figure 6h 1ihFFF=5P/(CL ) (kN/m) cCB uB uThe symbols in Fig 3, 4 and 5 indicate:i : minimum centre distance between two rowsof side blocks, in mP, L c , C : quantities described in [4.4.1]B, B m , B u : breadths described in [1.2.7]b) Bending moment and shear force1) Transverse sagging bending moment M t ins , perlength unit of the dock, in kN/mM t sag = 1,25 FBwhere F and B are the quantities indicated in a) ofthis item [4.5.2]2) Transverse hogging bending moment, per length unitof the dock, in kN/mM t hag = D v / (L c B)where D v is the light displacement of the dock, intonnes3) Shear forceT = the greater value of shear force per length unit ofthe dock, in kN/m, given by the following two relations:T 1 = (D v · B m ) / 5L c BT 2 = 6 Fwhere D v , B m , B, L c assume the values definedabove.4.5.3 Building docksa) Load on floorBWhenever the load that may be assumed on the transversesections of the dock may be reasonably representedby a concentrated force but it is moreconsistently represented by a continuous distribution,the conventional load assumes the shape illustrated byFig 6.h 1 = 5,4· P/(C² LcB u (kN/m ² )h = 6,4· P/(C² LcB u (kN/m ² )where P, C, L c , B u are the quantities indicated in [4.5.2]and the total value of the dashed area is equal to P/(C L c )in t per length unit of the dock.b) Bending moment and shear force1) Transverse sagging bending moment per length unitof the dock, kNm/mM t sag = (1,25 - C · B u /B) · P / (C L c ) · B2) Transverse hogging bending moment per length unitof the dock, kNm/mM t hag = (D v /L c ) · B3) Shear forceT = the greater value of the shear force per lengthunit of the dock, kN/m, given by the following tworelations:T 1 = (D v · B m ) / (L c B)T 2 = ( 1 - C B u / B) 6P / (C L c )D v , B and B m have the meanings defined above.4.6 Local strength4.6.1 GeneralThe structural scantlings determined applying the requirementsfor the check of the longitudinal and transversestrength are to be verified in order to ensure that the allowablestate is not exceeded due to local loads. The conventionalcalculation heads, to be assumed for the purpose ofthe above-mentioned checks for the various parts of thedock, are given in [4.6.2].As an alternative, the extreme differential heads anticipatedin operation may be considered in order to determine thehydrostatic loads acting on the various parts of the dock; insuch case a detailed description of the methods of operationand the checks foreseen is to be submitted to RINA forexamination.Relevant directions are to be reported in the operating manualof the dock.When the check of the local strength of the structure is carriedout considering the loads due to the extreme differentialloads, it is also to be verified that, in the presence of theheaviest load foreseen in the following items, the state ofstructures is compatible with the limit state. RINA maywaive this requirement, provided that a double check systemis foreseen, to be submitted for prior approval, ensuring20 Rules for floating docks 2010