Section 2 Bulkhead Laminates of Deep Tanks

201. Thickness of Bulkhead Laminates of Single Skin Construction

The thickness of bulkhead laminates of single skin construction is not to be less than obtained from the following formula:

ᾼ Ņ ÌĮĊΡ̓Üᾜ Nmm Ń

where,

Ċ : Spacing of stiffeners (m ).

ᾜ : Vertical distance measured from the lower edge of bulkhead laminate to the mid-point of the height between the top of overflow pipe and the top of tank (m ).

202. Thickness of Bulkhead Laminates of Sandwich Construction

1. The aggregated thickness of the inner layer, outer layer and core of the bulkhead laminates of sandwich construction is not to be less than obtained from the following formulae, whichever is greater:

ᾼÌ Ņ ǼÌĊᾜ Nmm Ń ᾼĪ Ņ ǼĪᾼᾚ Nmm Ń

Where,

ᾼᾚ : Thickness in case of single skin construction specified in 201. (mm ).

Ċ : Spacing of stiffeners (m ).

ᾜ : As specified in 201. (m ).

ǼÌ and ǼĪ : As specified in Ch 6, 303. 1.

2. The respective thicknesses of the inner layer and outer layer of bulkhead laminates of sandwich construction are not, notwithstanding the requirements in the preceding 1, to be less than obtained from the following formula. In no case, however, is it to be less than 2.4 mm .

ᾼ Ņ ĮǾĴΡ̓Į

Ĩ

ÜǼ NĊᾜŃĨ Nmm Ń

where,

Ċ : Spacing of stiffeners (m ).

ᾜ : As specified in 201 (m ).

ǼĨ : As specified in Ch 6, 303. 2.

203. Bulkhead Laminates of Structural Plywood 【See Guidance】

Where structural plywood are used for bulkhead plates, the thickness of plywoods is not to be less than specified by the requirements in 201. multiplied by the coefficient given in Ch 1, 304. 2 (1). However, is to be taken as bending strength (kgÕmmĪ ) of plywoods.

204. Bulkhead Stiffeners

The section modulus of bulkhead stiffeners is not to be less than obtained from the following for- mula:

Ě Ņ ǼĊᾜᾨĪ NcmĮ Ń

where,

Ċ and ᾨ : As specified in Ch 12, 204.

ᾜ : Vertical distance measured from the mid-point of ᾨ to the mid-point of the height between the top of overflow pipe and the top of tank (m ).

Ǽ : Coefficient given below:

(1) Where the both ends of stiffeners are attached by brackets --- 28

(2) Where the ends of stiffeners are snipped 42

205 Girders supporting Bulkhead Stiffeners

The section modulus of girders supporting frames and bulkhead stiffeners is not to be less than ob- tained from the following formula:

Ě Ņ ĨĪĊᾜ ᾨĪ Ncm Į Ń

where,

ᾨ : Total length of girders including the length of end connection (m ).

Ċ : Breadth of the area supported by the girders (m ).

ᾜ : Vertical distance measured from the mid-point of S to the mid-point of the height between the top of overflow pipe and the top of tank (m ).

206. Hat-type Construction

The scantlings of bulkhead stiffeners and girders of hat-type construction are to be in accordance with the requirements in Ch 1, 305. in addition to those in this chapter.

207 Structural Members forming Top and Bottom of Deep Tanks

The scantling of the structural members forming the top and the bottom of deep tanks are to be in accordance with the requirements in this chapter regarding the members as the bulkheads of deep tanks at the location. In no case, however, are they to be less than required for the deck laminates, etc. at the location.