Section 2 Arrangements of Construction Forward of the Collision Bulkhead

201. Constructions and arrangements

1. In the place forward of the collision bulkhead, the deep centre girder or the longitudinal bulkhead at the centre line is to be provided, or trusses connecting the centre girder with the deck con- struction by struts and diagonals are to be arranged.

2. In barges with transverse framing, the floors having sufficient depth are to be arranged in every frame and they are to be supported by the side girders provided at an interval of about 2.5 m and below. Frames are to be supported by the construction specified in 202. 5 to 7 with the spacing of about 2.5 m.

3. In barges with longitudinal framing, bottom and side longitudinals are to be supported by bottom and side transverse girders provided at an interval of about 2.5 m. Bottom and side transverse gird- ers are to be supported by side girders and side longitudinal girders or cross tie provided at an in- terval of about 4.6 m, respective1y. And side transverse girders are to be effectively connected with bottom transverse girders.

202. Transverse framing

1. The thickness of floors and centre girders is not to be less than obtained from the following for- mula, but need not exceed 11 mm.

ᾼ Ņ LǾLĨJ Ã Ñ ĨǾJ (mm)

2. The floors are to be of adequate depth and to be properly stiffened with stiffeners as may be required.

3. The upper edges of the floors and centre girders are to be properly stiffened.

4. The thickness of side girders is to be approximate1y equal to that of centre girders and side gird- ers are to extend to such a proper height as may be required according to the height of floors.

5. Where the panting beams are provided at every frame together with perforated steel plates fitted up thereon from side to side, the scantlings of panting beams and steel plates are not to be less than obtained from the following formula:

Sectional area of panting beams : A Ņ LǾÌ Ã Ñ J

Thickness of steel plates : ᾼ Ņ LǾLĪ Ã Ñ ĨǾJ (mm)

(cm2)

6. Where the side stringers are provided, their scantlings are not to be less than obtained from the following formula:

Depth: ᾘÌ Ņ ĪLLᾨ (mm), 2.5 times the depth of slots for transverse frames or the value obtained following formula, whichever is the greatest.

à P 90 m : ᾘĪ Ņ JǾĮ Ã Ñ ĪJL à ≥ 90 m : ᾘĪ Ņ ĪǾJ Ã Ñ JLL (mm)

Section modulus: Ě Ņ K ĊᾜᾨĪ

(cm3)

Thickness of web: ᾼ Ņ LǾLĪ Ã Ñ JǾJ (mm)

where:

Ċ = Breadth of area supported by the side stringer (m)

h = Vertical distance from the centre of Ċ to a point of 0.12Ã above the top of the keel (m), but not to be less than 0.06Ã

l = Distance between the supports of side stringers (m)

7. Where panting beams are provided on alternate frames and stringer plates which are connected to

the shell plating are provided at each tier of panting beams, the scantling of panting beams stringer plates are to comply with the following requirements.

and

Sectional area of panting beam : A Ņ LǾĮ Ã (cm2) Scantlings of stringer plates :

Breadth: Ã P 90 m : ᾎ Ņ JǾĮ Ã Ñ ĪJL

(mm)

à ≥ 90 m : ᾎ Ņ ĪǾJ Ã Ñ JLL (mm)

203. Longitudinal framing

1. Where the bottom transverses are supported along the than obtained from the following formula:

centre line, their scantlings are not to be less

Web depth: ᾘÌ Ņ ĪLLᾨ (mm) or ᾘĪ Ņ KǾJ Ã Ñ ÌKL (mm), whichever is the greater.

Section modulus : Ě Ņ ÌǾĪ ĊÃᾨ Ī

ĊÃᾨ

(cm3)

Web thickness : ᾼÌ Ņ

J ÜᾘL

Ñ ÌǾJ (mm) or ᾼĪ Ņ LǾĴΡ̓ÜÃ

Ñ ĮǾL (mm), whichever is the greater.

where:

Ċ = Spacing of transverses (m)

l = Span of transverses between the supporting points (m)

d0 = Depth of transverses deducted by the depth of slot for longitudinals (m)

2. The scantlings of centre girders are not to be less than those of bottom transverses specified in

Par 1.

3. The scantlings of side transverses supporting longitudinals are not to be less than obtained from the following formula:

Web depth: ᾘÌ Ņ ĪLLᾨL (mm) or 2.5 times the depth of slots for longitudinals (mm), whichever is the greatest.

à P 90 m : ᾘĪ Ņ JǾĮ Ã Ñ ĪJL (mm), à ≥ 90 m : ᾘĪ Ņ ĪǾJ Ã Ñ JLL (mm)

L

Section modulus: Ě Ņ K Ċᾜᾨ Ī

ĊÃᾨL

(cm3)

Ñ ǾJ (mm) or ᾼĪ Ņ LǾLĪ Ã Ñ JǾJ (mm), whichever is the greater.

L

Thickness of web: ᾼÌ Ņ ĨĪÜᾘ Ì

where:

Ċ = Spacing of transverses (m)

ᾘL = As specified in Par 1.

h = Vertical distance from the centre of ᾨL to a point of 0.12Ã (m) above the top of keel (m), but in no case is it to be less than 0.06Ã (m)

ᾨL = Length of side transverses between the supporting points (m)

4. Side transverses are to be provided with stiffeners on webs at every longitudinals.

5. The scantlings of side stringers which support side transverses are not to be less than obtained from the following formula:

Web Depth: ᾘÌ Ņ ĪLLᾨÌ (mm) or the value obtained from the following formula, whichever is the greater.

à P 90 m : ᾘĪ Ņ JǾĮ Ã Ñ ĪJL (mm), à ≥ 90 m : ᾘĪ Ņ ĪǾJ Ã Ñ JLL (mm)

L Ì

Section modulus: Ě Ņ Ĩ Ċᾜᾨ ᾨ (cm 3)

ĊᾜᾨÌ

Ñ ǾJ (mm) or ᾼĪ Ņ LǾLĪ Ã Ñ JǾJ (mm), whichever is the greater.

L

Thickness of web : ᾼÌ Ņ ĮÌÜᾘ Ì

where :

Ċ = Breadth of area supported by the stringer (m)

h = Vertical distance from the centre of Ċ to a point of 0.12Ã but in no case is it to be less than 0.06Ã (m)

ᾨL = As specified in Par 3.

ᾨÌ = Length of side stringers (m)

ᾘL = As specified in Par 1.

6. The sectional area of cross ties supporting the transverses is not to following formula:

(m) above the top of keel (m),

be less than obtained from the

Where l

k

is 0.6 and above: A Ņ

LǾKK Ċᾎᾜ

Üᾨ ÌŇLǾJÜᾟ

(cm2)

Where l k

is less than 0.6 : A Ņ ÌǾÌ Ċᾎᾜ (cm2)

where :

Ċ = Spacing of transverses (m)

ᾎ = Breadth of area supported by the cross ties (m)

h = Vertical distance from the centre of b to a point of 0.12 Ã

but in no case is it to be less than 0.06 Ã (m)

l = Length of cross ties (m)

(m) above the top of keel (m),

ᾟ = Minimum radius of gyration of cross ties, obtained from the following formula (cm)

ᾟ Ņ ÜAĀ

Ā = The least moment of inertia of the cross ties (cm4)

A = Sectional area of the cross ties (cm2)

204. Trusses

The truss structure connecting the bottom and the deck is to comply with the following require- ments:

(1) The sectional area of struts is not to be less than obtained from the following formula:

LǾĮĮ ĊᾎÃ A Ņ Üᾨ

ĪǾKĪ Ň Ü

where:

Ċ = Distance

(cm2)

between the mid-points of two adjacent spans of girders supported by the

struts or bulkheads (m)

ᾎ = Distance between the mid-points of two adjacent spans of beam supported by the struts or the beam brackets at ship side (m)

l = Length of struts (m)

ᾟ = Minimum radius of gyration of struts, obtained from the following formula (cm)

ᾟ Ņ ÜAĀ

Ā = The least moment of inertia of the strut (cm4)

A = Sectional area of the strut (cm2)

(2) Diagonals in trusses are to be arranged at an angle of inclination of about 45 deg, and the sec- tion area is not to be less than 0.75 times the area specified in (1).

(3) Where the fore peak is used for a deep tank, struts and diagonals are to be of solid section.