Deck structure

2.1 General

2.1.1 Where the upper deck is longitudinally framed outside the line of openings in the midship region, this system of framing is to be carried as far forward as possible. In the case of oil tankers, longitudinal framing is to extend to at least the forward end of the cargo tank section.

2.2 Deck plating

2.2.1 The thickness of strength/weather deck plating is to comply with the requirements of Table 5.2.1.

2.2.2 The thickness of lower deck plating is to comply with the requirements of Table 5.2.2.

2.2.3 The taper thickness of the strength deck stringer plate is to be increased by 20 per cent at the end of a forecastle or bridge where the end bulkhead is situated aft of 0,25L from the F.P. No increase is required where the end bulkhead lies forward of 0,2L from the F.P. The increase at intermediate positions is to be determined by interpolation.

2.2.4 The deck plating thickness and supporting

structure are to be suitably reinforced in way of the anchor windlass and other deck machinery, and in way of cranes, masts or derrick posts.

2.2.5 Where long, wide hatchways are arranged at lower decks, it may be necessary to increase the deck plating thick- ness to ensure effective support for side framing.

2.3 Deck stiffening

2.3.1 The scantlings of strength/weather deck longitudi- nals are to comply with the requirements of Table 5.2.3.

2.3.2 The scantlings of cargo and accommodation deck longitudinals are to comply with the requirements given in Table 1.4.4 in Pt 4, Ch 1.

2.3.3 End connections of longitudinals to bulkheads are to provide adequate fixity, lateral support and, so far as practicable, direct continuity of longitudinal strength.

2.3.4 The scantlings of weather deck beams are to comply with the requirements of Table 5.2.4.

2.3.5 The scantlings of lower deck beams are to comply with the requirements of Table 1.4.5 in Pt 4, Ch 1.

Part 3, Chapter 5

Section 2

Symbols Location Thickness, in mm

(1) Forward of 0,075L from the F.P. (2) Between 0,075L and 0,2L from

the F.P.

(3) Aft of 0,2L from the F.P.

(4) Inside forecastle extending aft of 0,15L from the F.P.

(5) In way of crown of a tank

L, D, T, s, S, k,rÿas defined in 1.4.1

C =

(

)

but is to be taken not greater than 1,0 nor less than 0,9

s₁ = s, but to be taken not less than s_b

s_b = standard frame spacing as follows: (a) forward of 0,05L from the F.P.:

s_b=

(

470 +

)

mm or 600 mm, whichever is the lesser

(b) between 0,05L and 0,2L from the F.P.:

s_b=

(

470 +

)

mm or 700 mm, whichever is the lesser

f = 1,1 – but to be taken not greater

than 1,0

h₄ = tank head, in metres, as defined in Ch 3,5

s 2500S L 0,6 L 0,6 D + 2,3 – T

height of deck above load waterline at F.P.

NOTES

1. The taper thickness is to be determined from Table 3.2.1 in Chapter 3.

2. For taper area requirements, see Table 3.2.1 in Chapter 3. 3. For thickness of upper deck plating in way of the cargo and fore

peak tanks of oil tankers or ore carriers, see also Pt 4, Ch 9, Ch 10 or Ch 11, as applicable.

4. The exposed deck taper thickness is to extend into a forecastle or bridge for at least one-third of the breadth of the ship from the superstructure end bulkhead.

The greater of the following: (a) t =

(

5,5 + 0,02L

)

C

(b) the taper thickness (see Notes 1, 2 and 3)

(c) for oil tankers, the thickness is also to be in accordance with Pt 4, Ch 9,4.3.3

k_s1 sb

The taper thickness (see Notes 1, 2 and 3) or as (2) (c) whichever is the greater As for a lower deck (see Note 4)

or as in (1) to (4) as applicable, whichever is the greater but not less than:

7,5 mm where L_{³ 90 m, or} 6,5 mm where L < 90 m

Table 5.2.1 Strength/weather deck plating forward (excluding forecastle deck)

t =

(

6,5 + 0,02L

)

C ks1 sb

t = 0,004s f + 3,5r k h4

Fore End Structure

2.3.6 End connections of beams are to be in accordance with the requirements of Ch 10,3.

2.4 Deck supporting structure

2.4.1 The arrangements and scantlings of supporting structure are generally to be in accordance with the require- ments given in Pt 4, Ch 1,4 using the heads given in Ch 3,5 for the particular region concerned, except as required by 2.4.2 to 2.4.4.

2.4.2 The spacing of girders and transverses are generally not to exceed the values given in Table 5.2.5.

2.4.3 Primary structure in the topside tanks of bulk carriers is to comply with the requirements of Pt 4, Ch 7,7.

2.4.4 Primary structure in the cargo tanks of oil tankers and ore carriers is to be determined from Pt 4, Ch 9, Ch 10 or Ch 11, as applicable.

2.5 Deck openings

2.5.1 In dry cargo ships the requirements for deck open- ings given in Pt 4, Ch 1,4 are generally applicable throughout the forward region, except that forward of 0,25L from the F.P.: (a) The radii or dimensions of the corners of main cargo hatchway openings on the strength deck are to be in accordance with the requirements of Pt 4, Ch 1,4.5. The thickness of the insert plates, where required, is not to be less than 20 per cent greater than the adjacent deck thickness outside the line of openings, with a minimum increase of 3 mm.

(b) Insert plates will be required at lower decks in way of any rapid change in hull form to compensate for loss of deck cross-sectional area. Otherwise, insert plates will not normally be required.

(c) Compensation and edge reinforcement for openings outside the line of main hatchways will be considered, bearing in mind their position, the deck arrangements and the type of ship concerned.

2.5.2 For deck openings in way of the cargo tanks in oil tankers and ore carriers, see also Pt 4, Ch 9, Ch 10 or Ch 11, as applicable. For main cargo hatchway openings on bulk carriers and container ships, see also Pt 4, Ch 7 and Ch 8, as applicable.

RULES ANDREGULATIONS FOR THECLASSIFICATION OFSHIPS, July 2000

Part 3, Chapter 5

Section 2

LLOYD’SREGISTER OFSHIPPING 9

L, s, S, k,r as defined in 1.4.1

b = breadth of increased plating, in mm

f = 1,1 – s but is to be taken not greater 2500S

than 1,0

h₄ = tank head, in metres, as defined in Ch 3,5

K₂ = 2,5 mm at bottom of tank, or = 3,5 mm at crown of tank

s₁ = s, but is to be taken not less than

(

470 + L1

)

mm 0,6

A_f = girder face area, in cm2

L₁ = L but need not be taken greater than 190 m

Clear of cargo hatches t = In way of hatch side girders t = 1,1 Minimum b = 760 mm breadth A_f 1,8k A_f 1,8k

Symbols Location Thickness, in mm

(1) Forward of 0,075L from the F.P.

(3) Aft of 0,075L from the F.P., outside line of openings

(5) Plating forming the upper flange of underdeck girders

(4) In way of crown or bottom of tank (2) Aft of 0,075L from the F.P., inside

line of openings

t = 0,01 s₁ k

but not less than 6,5 mm

As determined by a taper line from the midship thickness to the end thickness given by (1)

t = 0,004 f s + K₂

or as in (1), (2) or (3) as applicable, whichever is the greater but not less than:

7,5 mm where L³ 90 m, or 6,5 mm where L < 90 m

r k h4 1,025

NOTES

1. Where the deck loading exceeds 43,2 kN/m2 (4,4 tonne-f/m2_{), the thickness of plating will be} specially considered. This is equivalent to a ’tween deck height of 6,1 m in association with the stan- dard stowage rate of 1,39 m3_/tonne.

2. For minimum thickness of deck plating in oil tankers, see Pt 4, Ch 9,10.2.

Table 5.2.2 Lower deck plating forward

t = 0,01 s₁ k

Fore End Structure

Part 3, Chapter 5

Section 2

Location Modulus, cm3 _{Inertia, cm}4

(1) Forward of 0,075L from the F.P. The greater of the following:

(a) Z = sk(635h₁+ 0,0078(l_eL₁)2_{) x 10}–4 (b) Z = 0,0127skh₁l_e2

The greater of the following:

(a) Z_e= sk(485h_o+ 0,0062(l_{e 1}L₁)2_{) x 10}–4 (b) Z_e= 0,009skh_ol_e12

The greater of the following:

(a) Z = sk(570h₁+ 0,0072(l_eL₁)2_{) x 10}–4 (b) Z = 0,0127skh₁l_e2

The greater of the following:

(a) Z = sk(400h₁+ 0,005(l_eL₁)2_{) x 10}–4 (b) Z = 0,007skh₁l_e2 As (1) to (5), as applicable, or Z = 0,0113r skh4le 2 b

whichever is the greater

As given by (4) or as determined from Table 3.2.1 in Chapter 3 whichever is the greater, see Note 1 (2) At 0,075L from the F.P., for end modulus for taper

(3) Aft of 0,075L from the F.P., outside line of openings

(4) At 0,075L and between 0,075L and 0,12L from the F.P.

(5) Aft of 0,12L from the F.P., inside line of main cargo hatchways openings

(6) In way of the crown of a tank

–– –– –– –– I = 2,3 leZ k –– Symbols L, s, k_L, k, r as defined in 1.4.1

b = 1,4 for rolled or built sections = 1,6 for flat bars

d_w = web depth of longitudinal, in mm

h_o = 1,2 m for dry cargo ships = L1 m for oil tankers

56

h₁ = weather head, in metres, as defined in Ch 3,5 for dry cargo ships

= L1 m for oil tankers 70

h₄ = tank head, in metres, as defined in Ch 3,5

l_e as defined in 1.4.1, but is to be taken not less than 1,5 m

l_e1 is to be taken as the maximum span in metres in the midship cargo tank region for oil tankers and equal to l_efor dry cargo ships

L₁ = L but need not be taken greater than 190 m

NOTES

1. For area taper requirements, see also Table 3.2.1 in Chapter 3. 2. Where weather decks are intended to carry deck cargo and the loading is in excess of 8,5 kN/m2_{(0,865 tonne-f/m}2_{), the scant-} lings of longitudinals may be required to be increased to comply with the requirements for location (1) in Table 1.4.4 in Pt 4, Ch 1 using the equivalent design head, for specified cargo loadings, for weather decks given in Table 3.5.1 in Chapter 3.

3. For the scantlings of deck longitudinals forward in way of the cargo tanks of oil tankers or ore carriers, see also Pt 4, Ch 9, Ch 10 or Ch 11, as applicable.

4. The thickness of flat bar longitudinals situated outside the line of openings is to be not less than the following:

(a) t = mm

where longitudinal continuous through bulkhead (b) t = mm

where longitudinal cut at bulkhead

5. The web depth of longitudinal, d_w, is to be not less than 60 mm.

d_w

15 k_L

d_w

18 k_L

Fore End Structure

RULES ANDREGULATIONS FOR THECLASSIFICATION OFSHIPS, July 2000

Part 3, Chapter 5

Section 2

LLOYD’SREGISTER OFSHIPPING 11

B, D, T, s,r, k as defined in 1.4.1 b = 1,4 for rolled or built sections

= 1,6 for flat bars

h₁ = weather head, in metres, as defined in Ch 3,5

h₄ = tank head, in metres, as defined in Ch 3,5

l_e as defined in 1.4.1, but is to be taken not less than 1,83 m

K₁ = a factor dependent on the number of decks (including a bridge superstructure) at the position of the beam under consideration as follows:

1 deck 20,0

2 decks 13,3

3 decks 10,5

4 decks or more 9,3

For a forecastle deck, K₁is to be taken as 13,3

K₃ = a factor dependent on the location of the beam as follows: Span adjacent to ship’s side 3,6

Elsewhere 3,3

B₁ = B, but need not be taken greater than 21,5 m

Location Modulus, cm3 _{Inertia, cm}4

(1) Forward of 0,075L from the F.P. The lesser of the following:

(a) Z = k(800K₁TD + 5,4B₁sh₁l_e2_{) x 10}–4 (b) Z = 10,8B₁skh₁l_e2_{x 10}–4

The lesser of the following:

(a) Z = k(800K₁TD + K₃B₁sh₁l_e2_{) x 10}–4 (b) Z = 2K₃B₁skh₁l_e2_{x 10}–4

As (1), (2) or (3), as applicable, or

Z =

whichever is the greater 0,0113r s k h₄l_e2

b

As required for location (1) of Table 1.4.5 in Pt 4, Ch 1 (2) Between 0,075L and 0,12L from the F.P.

(3) Aft of 0,12L from the F.P. (4) In way of the crown of a tank

–– –– I = 2,3 l_eZ k –– Symbols NOTES

1. Beams at the upper deck inside superstructures are to have scantlings determined as for a lower deck, see Table 1.4.5 in Pt 4, Ch 1.

2. Where weather decks are intended to carry deck cargo and the loading is in excess of 8,5 kN/m2_{(0,865 tonne-f/m}2_{), the} scantlings of beams are also to comply with the requirements for location (2) in Table 1.4.5 of Pt 4, Ch 1 using the equivalent design head, for specified cargo loadings, for weather decks given in Table 3.5.1 in Chapter 3.

3. The web depth of beams, d_w, is to be not less than 60 mm. 4. The scantlings of deck beams forward in way of the cargo tanks

of oil tankers or ore carriers will be specially considered, see Pt 4, Ch 9,1.3.10.

Location

Maximum spacing Girders in association with transverse framing

system (1) Forward of the collision bulkhead

(2) Between the collision bulkhead and 0,075L from the F.P.

(3) In way of a deep tank, forward of 0,2L from the F.P.

(4) Elsewhere in way of dry cargo spaces or deep tanks, see Note 1

NOTES

1. For the maximum spacing of transverses in the cargo tanks of oil tankers or ore carriers, see Pt 4, Ch 9,9. 2. For the maximum spacing of transverses in dredgers, see Pt 4, Ch 12,5.

Transverses in association with longitudinal framing system

2,5 m where L£ 100 m 3,5 m where L_{³ 300 m}

Intermediate values by interpolation 3,0 m where L£ 100 m

4,2 m where L³ 300 m

Intermediate values by interpolation 3,8 m where L£ 100 m

(3,2 + 0,006L) m where L > 100m

Table 5.2.5 Spacing of girders and transverses under strength/weather decks forward Table 5.2.4 Weather deck beams forward

3,7 m

3,7 m

––

Fore End Structure

■

Section 3

In document Lloyds Register Rules and Regulations (Part_3_ship_structures) (Page 79-83)