Section 1 Structural design factors

1.1.1 The requirements of this Chapter are applicable to ships of steel construction.

1.2.1 This Chapter gives the allowable design criteria to be used to assess the structure.

1.2.2 These design criteria are to be used in the design formulae in Vol 1, Pt 6, Ch 3, 2 Minimum structural requirements as the design criteria for the scantling determination of NS2 and NS3 ships.

1.2.3 These criteria are also to be used when direct calculation methods are proposed as a supplement to the scantling determination procedures for all ships including NS1 ships.

1.2.4 For finite element and grillage analysis, the deflection criteria will be specially considered based on the function of the structure, analysis, and the type of load cases applied.

1.2.5 Where higher tensile steel is used in the ship structure special consideration is to be given to the fatigue performance in accordance with Vol 1, Pt 6, Ch 6, 2.5 Mechanical properties for design

1.3.1  Where higher tensile steels are used, the yield stress is to be adjusted by a factor f _hts, where f _hts is to be taken from Table 5.1.1 High tensile steel stress correction factor f hts

1.3.2 The f _hts factor is to be separately calculated for stresses that are a direct consequence of global loads and for stresses that are a direct consequence of local loads, as indicated in Table 5.1.1 High tensile steel stress correction factor f hts

Table 5.1.1 High tensile steel stress correction factor f _hts

Minimum yield stress σo N/mm2	f hts factor
	Global loads	Local loads
235	1,000	1,00
265	0,964	1,00
315	0,956	1,00
355	0,919	1,00
>390	0,886	0,91
Note 1. Intermediate values may be obtained by linear interpolation. Note 2. The higher tensile steel stress correction factor fhts is applicable for NS1 ships as well as NS2 and NS3 ships.