11.1.1 Direct
calculations are to be employed in the derivation of scantlings where
required by the preceding Sections of this Chapter or by related provisions
included in Pt 3 Ship Structures (General).
11.1.2 Direct
calculation methods are also generally to be used where additional
calculations are required by the Rules in respect of unusual arrangements.
11.1.3 For
complex structural arrangements, e.g. a double plate transverse bulkhead
with stool in a centre hold, associated with plane wing tank bulkheads
supported by stringers and buttresses, an investigation of bottom
primary structure over a full cargo hold length and three-dimensional
analysis of the transverse bulkhead structure will generally be required,
taking account of applied longitudinal hull bending effects.
11.1.4 The
cross-deck structure is to be verified as being capable of supporting
transverse compressive stresses resulting from lightship weight, deadweight,
hydrostatic and wave loads. For ore carriers that are designed to
operate with an asymmetrical loading condition, or large ore carriers
with B ≥ 40 m or b/w ≥ 2,2, the wave
loads should take account of hydrodynamic torque in an oblique sea.
The cross-deck structure is to comprise the hatch coamings and beams,
the plating and attached stiffeners and the upper stool. Non-corrugated
bulkhead plating may also be included
|
|
= |
where |
|
B
|
= |
moulded
breadth, in metres |
|
b
|
= |
breadth
of the deck hatch openings, in metres |
|
w
|
= |
width
of the cross-deck strip between hatchways, in metres. |