5 Connection Details

5.1 Bilge keels

5.1.1

The ground bar is to be connected to the shell with a continuous fillet weld, and the bilge keel to the ground bar with a continuous fillet weld in accordance with Table 5.

Table 5 : Connections of bilge keels

Structural items being joined	Leg length of weld, in mm
Structural items being joined	At ends⁽¹⁾	Elsewhere
Ground bar to the shell	0.62 t_{1as_built}	0.48 t_{1as_built}
Bilge keel web to ground bar	0.48 t_{2as_built}	0.30 t_{2as_built}
t_1as-built: As-built thickness of ground bar, in mm. t_2as-built :As-built thickness of web of bilge keel, in mm. ⁽¹⁾ : Zone “b” in Fig. 19 and Fig. 20 in Pt 1 Ch 3 Sec 6 for definition of “ends”

5.1.2

Butt welds, in the bilge keel and ground bar, are to be well clear of each other and of butts in the shell plating as shown in Figure 10. In general, shell butts are to be flush in way of the ground bar and ground bar butts are to be flush in way of the bilge keel. Direct connection between ground bar butt welds and shell plating is not permitted. This may be obtained by use of removable backing.

5.1.3

The ground bar is to be continuously fillet welded with a leg length as given in Table 5. At the ends of the ground bar, the leg length is to be increased as given in Table 5, without exceeding the as-built thickness of the ground bar as shown in Figure 10. The welded transition at the ends of the ground bar to the plating connection should be formed with the weld flank angle of 45 deg or less.

5.1.4

In general, scallops and cut-outs are not to be used. Crack arresting holes are to be drilled in the bilge keel butt welds as close as practicable to the ground bar. The diameter of the hole is to be greater than the width of the butt weld and is to be a minimum of 25 mm. Where the butt weld has been subject to non-destructive examination, the crack arresting hole may be omitted.

5.2 Bulk carrier side frames

5.2.1

The following requirements are applicable to side frames, end brackets and tripping brackets of single side skin bulk carriers.

Figure 10 : Bilge keel

5.2.2

For zones ‘a’ and ‘b’ as shown in Figure 11, double continuous fillet welding should be used with leg lengths of 0.62 t_as-built and 0.57 t_as-built respectively, where t_as-built is the as-built thickness of the thinner of two connected members, in mm.

5.2.3

Double continuous welding is to be adopted for the connections of tripping brackets with side shell frames and plating. The leg length, ℓ_leg in mm, for these connections should be taken as:

0.5 t_{as_built} + 1.0 if t_as-built < 10
0.4 t_{as_built} + 2.0 if 10 ≤ t_as-built < 20
0.3 t_{as_built} + 4.0 if t_as-built ≥ 20.

In these formulas t_as-built is as-built thickness of the abutting plate.

5.3 End connections of pillars and cross ties

5.3.1

The end connections of pillars and cross ties are to have an effective fillet weld area, in cm², (weld throat multiplied by weld length) not less than:

where:

F : Design load, for the structure under consideration, in kN.

f₃ : Coefficient equal to:

f₃ = 0.05 when pillar or cross tie is in compression only.
f₃= 0.14 when pillar or cross tie is in tension.

Figure 11 : Bulk carrier side frames

5.4 Abutting plates with small angles

5.4.1

Where the angle θ between the abutting plate and the connected plate is less than 75 deg as shown in Figure 12, the size of fillet welds ℓ_θ, in mm, for the side of larger angle is to be increased in accordance with:

where:

ℓ_leg : Leg length of fillet weld, in mm, as defined in [2.5.2].

θ : Connecting angle, in deg, as shown in Figure 12.

Figure 12 : Connecting angle

5.4.2

Connections of main strength members where θ is less than 45 deg, see Figure 12, may be applied only in dry spaces and voids.