Section 2 Deflection control

2.1 General

2.1.1 The requirements in respect of limiting deflection for both panels and stiffening members are given in this Section. These limits are generally based on a span/deflection ratio, f _δ, as given in Table 7.2.1 Limiting span/deflection ratio, in consistent units.

2.1.2 Notwithstanding the values in Table 7.2.1 Limiting span/deflection ratio, the span/deflection ratio for panels subject to long-term static loading is to be less than 100.

Table 7.2.1 Limiting span/deflection ratio

Item		f _δ
Shell envelope
	sandwich construction	100
Bottom structure
	secondary stiffening	150
	primary girders and web frames	200
Side structure
	secondary stiffening	150
	primary girders and web frames	200
Main/strength deck structures
	sandwich construction	100
	secondary stiffening	200
	primary girders and web frames	250
	hatch covers	100
Superstructure/deckhouse laminates
(a) Generally	sandwich construction	50
(b) Coachroof	sandwich construction
	sandwich construction	100
(c) House top		50
(d) Lower/inner decks and house top subject to personnel loading
	sandwich construction	100
Superstructure/deckhouse stiffeners
(a) Generally	secondary	100
	primary	150
(b) Coachroof	secondary	150
	primary	200
(c) House top	secondary	100
	primary	100
(d) Lower/inner decks and house top subject to personnel loading
	secondary members	150
	primary members	200
Deep tank structures
(a) Laminates	sandwich construction	100
	secondary members	100
(b) Stiffeners	primary members	200
Watertight bulkhead structures
(a) Laminates	sandwich construction	50
	secondary members	50
(b) Stiffeners	primary members	150
Multihull cross-deck structures
(a) Laminates	sandwich construction	100
	secondary members	125
(b) Stiffeners	primary members	150
Vehicle deck structures
(a) Laminates	sandwich construction	100
(b) Stiffeners	secondary members	200
	primary members	250
Helicopter/flight decks
(a) Laminates	sandwich construction	100
(b) Stiffeners	secondary members	200
	primary members	250
Note Where significant curvature exists over the span of the stiffener or breadth of the panel, the allowable deflections will be specially considered.