Jurusan Teknik Sistem PerkapalanFakultas Teknologi Kelautan ITS Surabaya

2012

Jurusan Teknik Sistem PerkapalanFakultas Teknologi Kelautan ITS Surabaya

2012

Prepared by:

A.A. B. DinariyanaSoemartojo W.A.

Contents:

A.2. Definition

B. Bottom PlatingB.1. Plate thicknessB.1. Plate thicknessB.3. Minimum thicknessB.4. Bilge strakeB.5. Flat plate keel and garboard strake

C. Side Shell PlatingC.1. Plate thicknessC.2. Minimum thicknessC.3. Sheerstrake

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2.1 Load centre

2.1.1 For plates

Vertical stiffening system

The scantlings of ships shell plating are calculated based on

design load calculation found at Section 4 (BKI Vol. 2, 2009)

Vertical stiffening system0,5 stiffener spacing above the lower support of plate field, or lower edge of plate when the thickness changes within the plate field.

Horizontal stiffening system:Midpoint of plate field

2.1.2 For stiffeners and girders:Centre of span l

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z = vertical distance of the structures load centre above baseline, Section 4, A.2.2

k = material factor, Section 2.B.2tk = corrosion addition, Section 3.KPB, PBl = load on bottom [kN/m], Section 4.B.3Ps, Psl = load on sides [kN/m], Section 4.B.2.1.Pe = design pressure for the bow area [kN/m], Section 4.B.2.2. or

B.2.3. for the stern area.PSL = design slamming presure [kN/m],Section 4.B.4PSL = design slamming presure [kN/m],Section 4.B.4nf = 1,0 for transverse framing or = 0,83 for longitudinal framingLB = maximum bottom design hull girder bending stress

[N/mm], Section 5.D.1LS = maximum design hull girder bending stress [N/mm] in the

side shell at the station , Section 5.D.1.L = maximum design shear stress due to longitudinal hull girder

bending [N/mm], Section 5.D.1.perm = permissible design stress [N/mm]

= [ 0,8 + L/450] 230/k for L < 90 m= 230/k for L 90 m

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k = material factor, Section 2.B.2

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k = material factor, Section 2.B.2

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tk = corrosion addition, Section 3.K

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For structural elements

in specified areas see

Section 3.K for detail

For structural elements

in specified areas see

Section 3.K for detail

B.1.Plate thickness based on load stress criteria

B.1.1.Ships with lengths L < 90 m

The thickness of the bottom shell plating within 0,4 L amidships is not to be less than:L amidships is not to be less than:

Within 0,1 L forward of the aft end of the length L and within 0,05 L aft of F.P, the thickness is not to be less than:

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B.1.1.Ships with lengths L < 90 m

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See nextslide

See nextslide

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Restricted ocean service

Coastal service

Shallow water service

B.1.Plate thickness based on load stress criteria B.1.2. Ships with lengths L 90 m

The thickness of the bottom plating is not to be less than the greater of the two following values:

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See next slide for

remaining notation

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See maximum design shear

stress due to longitudinal

hull girder bending LIn Table 5.3 (Section 5, D)

At no point the thickness of the bottom shell plating shall be less than :

L need not be taken greater than 12 H.

For bulk carriers see Section 23, B.5.3, for tankers see Section 24, A.13.3.

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Higher steel grade than A/AH (see Section 2,B) is required for bilge strake.

According to Section 6, B.4.2, The thickness According to Section 6, B.4.2, The thickness of the bilge strake must not be less than the thickness of bottom plating (Section 6, B.1) , minimum thickness (Section 6, B.3), and side shell plating (Section 6, C.1) respectively.

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The width of bilge strake is not to be less than

At the end of the curved bilge strake longitudinal At the end of the curved bilge strake longitudinal stiffeners or girders are to be arranged.

When the stiffeners are arranged outside the bilge radius sufficient buckling resistance according to Section 3, F. is to be shown for the plane plate fields see Section 6,B.4.3 for detail

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The width of the flat plate keel is not to be less than:

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For ships exceeding 100 m in length, the bottom of which is longitudinally framed, the flat plate keel is to be stiffened by additional intercostal stiffeners fitted at a distance of intercostal stiffeners fitted at a distance of approx. 500 mm from centre line.

The sectional area of one longitudinal stiffener should not be less than 0,2 L [cm2].

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Where a bar keel is arranged, the adjacent garboard strake is to have the scantlings of a flat plate keel.

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C.1. Plate thickness based on load stress criteria C.1.1. Ships with lengths L < 90 m

The thickness of the side shell plating within 0,4 L amidship is not to be less than:

Within 0,1 L forward of the aft end of the length L and within 0,05 L aft of F.P. the thickness is not to be less than

*

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C.1. Plate thickness based on load stress criteria C.1.2. Ships with lengths L 90 m

The thickness of the side shell plating is not to be less than the greater of the two following values:

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perm = [230/k] - 3 .L - 0,89. LS [N/mm]

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For the minimum thickness of the side shell plating B.3. applies accordingly. At no point the thickness of the bottom shell plating shall be less than :

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Above a level T + c0/2 above base line smaller thicknesses than tmin may be accepted if the stress level permits such reduction.

co = wave coefficient see Section 42.2

The width of the sheerstrake is not to be less than:

The thickness of the sheer strake shall, in general, not be less than the greater of the following two values:

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Peraturan Biro Klasifikasi Indonesia Volume II, Edition 2009

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