3 Transverse Corrugated Bulkheads of Ballast Holds

3.1 Plate thickness

3.1.1 The net thickness of web and flange plating is not to be less than the values obtained in Pt 1, Ch 6, Sec 3, [1.1.1] and Pt 1, Ch 6, Sec 4, [1.2].

3.2 Net section modulus

3.2.1 The net section modulus Z, in cm³, of corrugated bulkhead of ballast holds, subjected to lateral pressure are not to be less than the values obtained from the following formula:

where:

K : Coefficient given in Table 1 and Table 2, according to the type of end connection. When d_H< 2.5 d₀, both section modulus per half pitch of corrugated bulkhead and section modulus of lower stool at inner bottom are to be calculated.

P : Design pressure for the design load set as defined in Pt 1, Ch 6, Sec 2, Table 1 and calculated at the load calculation point defined in Pt 1, Ch 3, Sec 7, [3.2], in kN/m².

s_C : Half pitch length, in mm, of the corrugation, as defined in Pt 1, Ch 3, Sec 6, Figure 21.

ℓ : Length, in m, between the supports, as indicated in Figure 1.

C_s : Coefficient defined in Pt 1, Ch 6, Sec 5, [1.1.2].

f_bdg: Coefficient defined in Pt 1, Ch 6, Sec 5, [1.1.2].

The effective width of the corrugation flange in compression is to be considered according to Ch 1, Sec 3, [3.3.1] when the net section modulus of corrugated bulkhead is calculated.

Table 1 : Values of K, in case d_H ≥ 2.5d₀

Upper end support
Welded directly to deck	Welded to stool efficiently supported by ship structure
1.00	0.83

Table 2 : Values of K, in case d_H < 2.5d₀

Section modulus of	Upper end support
Section modulus of	Connected to deck	Connected to stool
Corrugated bulkhead	0.71	0.65
Stool at bottom	1.25	1.13

Figure 1 : Measurement of ℓ

3 Transverse Corrugated Bulkheads of Ballast Holds

Table 1 : Values of K, in case dH ≥ 2.5d0

Table 2 : Values of K, in case dH < 2.5d0

Table 1 : Values of K, in case d_H ≥ 2.5d₀

Table 2 : Values of K, in case d_H < 2.5d₀