Section 2 Bending Strength

201.

Section modules of hull

1. The section modules of the hull for the midship part is not to be less than obtained from the fol- lowing formula, whichever is the greater:

Ī 3

ĚÌ Ņ LǾĶJǼÌÃ Æ NǼᾎ Ñ LǾK Ń (cm )

Ī Ã 3

ĚĪ Ņ ĴǾĴĮǼÓÌǾĪKǼĪÃ ÆǼ NÌ ÑLǾLĨ Æ ŃÑBᾯŎ (cm )

ᾎ Ü

where:

ǼÌ = As obtained from the following where

Į

à is 90 m and above;

ǼÌ Ņ ÌLǾKJŇN ÜÌLL Ī

ĮLL Ň Ã Ń Ü

where à is under 90 m ; ǼÌ Ņ LǾLĮ Ã Ñ J

Cb = Block coefficient, the ratio of the volume of the moulded displacement corresponding to the load line to LBd.

C2 = As obtained from the following formula:

ǼĪ Ņ LǾLLĪKÃ ÑLǾĨĴ

C = As given in Table 4.1.

Table 4.1 Coefficient C

M s = Longitudinal bending moment in still water specified in Par 2 (kN⋅m).

2. The longitudinal bending moments in still water, M s , are taken the maximum sagging and hogging

moments calculated for all of designed loaded and ballast conditions by the method deemed appro-

priate by the Society. Furthermore, in a pusher barge, the effect of the joint part is to be consid-

ered to the longitudinal bending moment.

3. For barges less than 60 m in length the requirement of ĚĪ in Par 1 above may be dispensed with.

However, longitudinal bending moment in still water are to be calculated for barges designed for special loading or ballasting.

202. Calculation of hull section modules

As for calculation of the hull section modules, the following Par 1 through 6 are to be applied:

1. All longitudinal members which are considered effective to the longitudinal strength of the barge may be included in the calculation.

2. Deck openings on the strength deck are to be deducted from the sectional area used in the section modules calculation. However, small openings not exceeding 2.5 m in length or l.2 m in breadth need not be deducted, provided that the sum of their breadths in one transverse section is not more

than 0.06 (Æ Ň ∑ᾎ). Where, in length (m).

∑b is the sum of the openings exceeding 1.2 m in breadths or 2.5 m

3. Notwithstanding the requirement in Par 2, deck openings on the strength deck need not be de- ducted, provided that the sum of their breadths in one transverse section is not reducing the section modules at deck or bottom by more than 3 % .

4. Deck openings prescribed in Par 2 and 3 include shadow area which is obtained by drawing two tangential lines with an opening angle of 30 deg having the focus on the longitudinal line of the ship.

5. The section modules at the strength deck is to be calculated by dividing the moment of inertia of the athwartship section about its horizontal neutral axis by the following distance (1) or (2) which- ever is the greater.

(1) Vertical distance from the neutral axis to the top of the strength deck beam at side.

(2) Distance obtained from the following formula :

É Ĕ NLǾĶ Ñ LǾĪ ÜÆ Ń

where:

X = Horizontal distance from the top of continuous strength member to the centre line of the barge (m).

Y = Vertical distance from the neutral axis to the top of continuous strength member (m).

X and Y are to be measured to the point giving the largest value of the above formula.

6. The section modules at the bottom is to be calculated by diving the moment of inertia of the ath- wartship section about its horizontal neutral axis by the vertical distance from the neutral axis to the top of keel.