3 Stiffeners

3.1 Proportions of stiffeners

3.1.1 Net thickness of all stiffener types

The net thickness of stiffeners is to satisfy the following criteria:

a) Stiffener web plate:
b) Flange:

where:

C_w, C_f : Slenderness coefficients given in Table 1.

Figure 1 : Stiffener scantling parameters

Table 1 : Slenderness coefficients

Type of Stiffener	*C_w*	*C_f*
Angle, L2 and L3 bars	75	12
T-bars	75	12
Bulbbars	45	-
Flat bars	22	-

3.1.2 Net dimensions of angle and T-bars

The total flange breadth bf in mm, for angle and T-bars is to satisfy the following criterion:

b_f ≥ 0.25h_w

3.1.3 Bending stiffness of stiffeners

The net moment of inertia, in cm⁴, of the stiffener with the effective width of attached plate, about the neutral axis parallel to the attached plating, is not to be less than the minimum value given by:

where:

A_eff : Net sectional area of stiffener including effective attached plate, s_eff, in cm².

R_eH : Specified minimum yield stress of the material of the attached plate, in N/mm².

C : Slenderness coefficient taken as:

C = 1.43 for longitudinal stiffeners including sniped stiffeners.
C = 0.72 for other stiffeners.